0f71fa273f
Add a simple pass-thru filter as example implementation for the Git filter protocol version 2. See Documentation/gitattributes.txt, section "Filter Protocol" for more info. Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1161 lines
40 KiB
Plaintext
1161 lines
40 KiB
Plaintext
gitattributes(5)
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================
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NAME
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----
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gitattributes - defining attributes per path
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SYNOPSIS
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--------
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$GIT_DIR/info/attributes, .gitattributes
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DESCRIPTION
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-----------
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A `gitattributes` file is a simple text file that gives
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`attributes` to pathnames.
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Each line in `gitattributes` file is of form:
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pattern attr1 attr2 ...
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That is, a pattern followed by an attributes list,
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separated by whitespaces. When the pattern matches the
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path in question, the attributes listed on the line are given to
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the path.
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Each attribute can be in one of these states for a given path:
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Set::
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The path has the attribute with special value "true";
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this is specified by listing only the name of the
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attribute in the attribute list.
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Unset::
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The path has the attribute with special value "false";
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this is specified by listing the name of the attribute
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prefixed with a dash `-` in the attribute list.
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Set to a value::
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The path has the attribute with specified string value;
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this is specified by listing the name of the attribute
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followed by an equal sign `=` and its value in the
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attribute list.
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Unspecified::
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No pattern matches the path, and nothing says if
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the path has or does not have the attribute, the
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attribute for the path is said to be Unspecified.
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When more than one pattern matches the path, a later line
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overrides an earlier line. This overriding is done per
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attribute. The rules how the pattern matches paths are the
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same as in `.gitignore` files; see linkgit:gitignore[5].
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Unlike `.gitignore`, negative patterns are forbidden.
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When deciding what attributes are assigned to a path, Git
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consults `$GIT_DIR/info/attributes` file (which has the highest
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precedence), `.gitattributes` file in the same directory as the
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path in question, and its parent directories up to the toplevel of the
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work tree (the further the directory that contains `.gitattributes`
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is from the path in question, the lower its precedence). Finally
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global and system-wide files are considered (they have the lowest
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precedence).
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When the `.gitattributes` file is missing from the work tree, the
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path in the index is used as a fall-back. During checkout process,
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`.gitattributes` in the index is used and then the file in the
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working tree is used as a fall-back.
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If you wish to affect only a single repository (i.e., to assign
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attributes to files that are particular to
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one user's workflow for that repository), then
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attributes should be placed in the `$GIT_DIR/info/attributes` file.
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Attributes which should be version-controlled and distributed to other
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repositories (i.e., attributes of interest to all users) should go into
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`.gitattributes` files. Attributes that should affect all repositories
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for a single user should be placed in a file specified by the
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`core.attributesFile` configuration option (see linkgit:git-config[1]).
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Its default value is $XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME
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is either not set or empty, $HOME/.config/git/attributes is used instead.
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Attributes for all users on a system should be placed in the
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`$(prefix)/etc/gitattributes` file.
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Sometimes you would need to override an setting of an attribute
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for a path to `Unspecified` state. This can be done by listing
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the name of the attribute prefixed with an exclamation point `!`.
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EFFECTS
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-------
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Certain operations by Git can be influenced by assigning
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particular attributes to a path. Currently, the following
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operations are attributes-aware.
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Checking-out and checking-in
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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These attributes affect how the contents stored in the
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repository are copied to the working tree files when commands
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such as 'git checkout' and 'git merge' run. They also affect how
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Git stores the contents you prepare in the working tree in the
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repository upon 'git add' and 'git commit'.
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`text`
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^^^^^^
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This attribute enables and controls end-of-line normalization. When a
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text file is normalized, its line endings are converted to LF in the
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repository. To control what line ending style is used in the working
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directory, use the `eol` attribute for a single file and the
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`core.eol` configuration variable for all text files.
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Note that `core.autocrlf` overrides `core.eol`
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Set::
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Setting the `text` attribute on a path enables end-of-line
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normalization and marks the path as a text file. End-of-line
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conversion takes place without guessing the content type.
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Unset::
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Unsetting the `text` attribute on a path tells Git not to
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attempt any end-of-line conversion upon checkin or checkout.
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Set to string value "auto"::
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When `text` is set to "auto", the path is marked for automatic
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end-of-line conversion. If Git decides that the content is
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text, its line endings are converted to LF on checkin.
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When the file has been committed with CRLF, no conversion is done.
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Unspecified::
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If the `text` attribute is unspecified, Git uses the
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`core.autocrlf` configuration variable to determine if the
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file should be converted.
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Any other value causes Git to act as if `text` has been left
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unspecified.
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`eol`
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^^^^^
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This attribute sets a specific line-ending style to be used in the
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working directory. It enables end-of-line conversion without any
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content checks, effectively setting the `text` attribute.
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Set to string value "crlf"::
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This setting forces Git to normalize line endings for this
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file on checkin and convert them to CRLF when the file is
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checked out.
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Set to string value "lf"::
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This setting forces Git to normalize line endings to LF on
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checkin and prevents conversion to CRLF when the file is
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checked out.
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Backwards compatibility with `crlf` attribute
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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For backwards compatibility, the `crlf` attribute is interpreted as
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follows:
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------------------------
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crlf text
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-crlf -text
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crlf=input eol=lf
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------------------------
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End-of-line conversion
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^^^^^^^^^^^^^^^^^^^^^^
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While Git normally leaves file contents alone, it can be configured to
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normalize line endings to LF in the repository and, optionally, to
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convert them to CRLF when files are checked out.
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If you simply want to have CRLF line endings in your working directory
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regardless of the repository you are working with, you can set the
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config variable "core.autocrlf" without using any attributes.
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------------------------
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[core]
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autocrlf = true
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------------------------
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This does not force normalization of text files, but does ensure
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that text files that you introduce to the repository have their line
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endings normalized to LF when they are added, and that files that are
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already normalized in the repository stay normalized.
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If you want to ensure that text files that any contributor introduces to
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the repository have their line endings normalized, you can set the
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`text` attribute to "auto" for _all_ files.
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------------------------
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* text=auto
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------------------------
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The attributes allow a fine-grained control, how the line endings
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are converted.
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Here is an example that will make Git normalize .txt, .vcproj and .sh
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files, ensure that .vcproj files have CRLF and .sh files have LF in
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the working directory, and prevent .jpg files from being normalized
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regardless of their content.
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------------------------
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* text=auto
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*.txt text
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*.vcproj text eol=crlf
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*.sh text eol=lf
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*.jpg -text
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------------------------
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NOTE: When `text=auto` conversion is enabled in a cross-platform
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project using push and pull to a central repository the text files
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containing CRLFs should be normalized.
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From a clean working directory:
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-------------------------------------------------
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$ echo "* text=auto" >.gitattributes
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$ rm .git/index # Remove the index to force Git to
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$ git reset # re-scan the working directory
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$ git status # Show files that will be normalized
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$ git add -u
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$ git add .gitattributes
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$ git commit -m "Introduce end-of-line normalization"
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-------------------------------------------------
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If any files that should not be normalized show up in 'git status',
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unset their `text` attribute before running 'git add -u'.
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------------------------
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manual.pdf -text
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------------------------
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Conversely, text files that Git does not detect can have normalization
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enabled manually.
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------------------------
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weirdchars.txt text
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------------------------
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If `core.safecrlf` is set to "true" or "warn", Git verifies if
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the conversion is reversible for the current setting of
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`core.autocrlf`. For "true", Git rejects irreversible
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conversions; for "warn", Git only prints a warning but accepts
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an irreversible conversion. The safety triggers to prevent such
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a conversion done to the files in the work tree, but there are a
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few exceptions. Even though...
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- 'git add' itself does not touch the files in the work tree, the
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next checkout would, so the safety triggers;
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- 'git apply' to update a text file with a patch does touch the files
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in the work tree, but the operation is about text files and CRLF
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conversion is about fixing the line ending inconsistencies, so the
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safety does not trigger;
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- 'git diff' itself does not touch the files in the work tree, it is
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often run to inspect the changes you intend to next 'git add'. To
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catch potential problems early, safety triggers.
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`ident`
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^^^^^^^
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When the attribute `ident` is set for a path, Git replaces
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`$Id$` in the blob object with `$Id:`, followed by the
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40-character hexadecimal blob object name, followed by a dollar
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sign `$` upon checkout. Any byte sequence that begins with
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`$Id:` and ends with `$` in the worktree file is replaced
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with `$Id$` upon check-in.
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`filter`
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^^^^^^^^
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A `filter` attribute can be set to a string value that names a
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filter driver specified in the configuration.
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A filter driver consists of a `clean` command and a `smudge`
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command, either of which can be left unspecified. Upon
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checkout, when the `smudge` command is specified, the command is
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fed the blob object from its standard input, and its standard
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output is used to update the worktree file. Similarly, the
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`clean` command is used to convert the contents of worktree file
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upon checkin. By default these commands process only a single
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blob and terminate. If a long running `process` filter is used
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in place of `clean` and/or `smudge` filters, then Git can process
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all blobs with a single filter command invocation for the entire
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life of a single Git command, for example `git add --all`. If a
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long running `process` filter is configured then it always takes
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precedence over a configured single blob filter. See section
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below for the description of the protocol used to communicate with
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a `process` filter.
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One use of the content filtering is to massage the content into a shape
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that is more convenient for the platform, filesystem, and the user to use.
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For this mode of operation, the key phrase here is "more convenient" and
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not "turning something unusable into usable". In other words, the intent
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is that if someone unsets the filter driver definition, or does not have
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the appropriate filter program, the project should still be usable.
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Another use of the content filtering is to store the content that cannot
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be directly used in the repository (e.g. a UUID that refers to the true
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content stored outside Git, or an encrypted content) and turn it into a
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usable form upon checkout (e.g. download the external content, or decrypt
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the encrypted content).
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These two filters behave differently, and by default, a filter is taken as
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the former, massaging the contents into more convenient shape. A missing
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filter driver definition in the config, or a filter driver that exits with
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a non-zero status, is not an error but makes the filter a no-op passthru.
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You can declare that a filter turns a content that by itself is unusable
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into a usable content by setting the filter.<driver>.required configuration
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variable to `true`.
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For example, in .gitattributes, you would assign the `filter`
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attribute for paths.
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------------------------
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*.c filter=indent
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------------------------
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Then you would define a "filter.indent.clean" and "filter.indent.smudge"
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configuration in your .git/config to specify a pair of commands to
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modify the contents of C programs when the source files are checked
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in ("clean" is run) and checked out (no change is made because the
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command is "cat").
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------------------------
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[filter "indent"]
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clean = indent
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smudge = cat
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------------------------
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For best results, `clean` should not alter its output further if it is
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run twice ("clean->clean" should be equivalent to "clean"), and
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multiple `smudge` commands should not alter `clean`'s output
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("smudge->smudge->clean" should be equivalent to "clean"). See the
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section on merging below.
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The "indent" filter is well-behaved in this regard: it will not modify
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input that is already correctly indented. In this case, the lack of a
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smudge filter means that the clean filter _must_ accept its own output
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without modifying it.
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If a filter _must_ succeed in order to make the stored contents usable,
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you can declare that the filter is `required`, in the configuration:
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------------------------
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[filter "crypt"]
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clean = openssl enc ...
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smudge = openssl enc -d ...
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required
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------------------------
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Sequence "%f" on the filter command line is replaced with the name of
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the file the filter is working on. A filter might use this in keyword
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substitution. For example:
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------------------------
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[filter "p4"]
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clean = git-p4-filter --clean %f
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smudge = git-p4-filter --smudge %f
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------------------------
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Note that "%f" is the name of the path that is being worked on. Depending
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on the version that is being filtered, the corresponding file on disk may
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not exist, or may have different contents. So, smudge and clean commands
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should not try to access the file on disk, but only act as filters on the
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content provided to them on standard input.
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Long Running Filter Process
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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If the filter command (a string value) is defined via
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`filter.<driver>.process` then Git can process all blobs with a
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single filter invocation for the entire life of a single Git
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command. This is achieved by using a packet format (pkt-line,
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see technical/protocol-common.txt) based protocol over standard
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input and standard output as follows. All packets, except for the
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"*CONTENT" packets and the "0000" flush packet, are considered
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text and therefore are terminated by a LF.
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Git starts the filter when it encounters the first file
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that needs to be cleaned or smudged. After the filter started
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Git sends a welcome message ("git-filter-client"), a list of supported
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protocol version numbers, and a flush packet. Git expects to read a welcome
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response message ("git-filter-server"), exactly one protocol version number
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from the previously sent list, and a flush packet. All further
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communication will be based on the selected version. The remaining
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protocol description below documents "version=2". Please note that
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"version=42" in the example below does not exist and is only there
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to illustrate how the protocol would look like with more than one
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version.
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After the version negotiation Git sends a list of all capabilities that
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it supports and a flush packet. Git expects to read a list of desired
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capabilities, which must be a subset of the supported capabilities list,
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and a flush packet as response:
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------------------------
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packet: git> git-filter-client
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packet: git> version=2
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packet: git> version=42
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packet: git> 0000
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packet: git< git-filter-server
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packet: git< version=2
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packet: git< 0000
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packet: git> capability=clean
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packet: git> capability=smudge
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packet: git> capability=not-yet-invented
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packet: git> 0000
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packet: git< capability=clean
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packet: git< capability=smudge
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packet: git< 0000
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------------------------
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Supported filter capabilities in version 2 are "clean" and
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"smudge".
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Afterwards Git sends a list of "key=value" pairs terminated with
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a flush packet. The list will contain at least the filter command
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(based on the supported capabilities) and the pathname of the file
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to filter relative to the repository root. Right after the flush packet
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Git sends the content split in zero or more pkt-line packets and a
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flush packet to terminate content. Please note, that the filter
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must not send any response before it received the content and the
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final flush packet.
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------------------------
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packet: git> command=smudge
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packet: git> pathname=path/testfile.dat
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packet: git> 0000
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packet: git> CONTENT
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packet: git> 0000
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------------------------
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The filter is expected to respond with a list of "key=value" pairs
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terminated with a flush packet. If the filter does not experience
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problems then the list must contain a "success" status. Right after
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these packets the filter is expected to send the content in zero
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or more pkt-line packets and a flush packet at the end. Finally, a
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second list of "key=value" pairs terminated with a flush packet
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is expected. The filter can change the status in the second list
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or keep the status as is with an empty list. Please note that the
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empty list must be terminated with a flush packet regardless.
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------------------------
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packet: git< status=success
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packet: git< 0000
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packet: git< SMUDGED_CONTENT
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packet: git< 0000
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packet: git< 0000 # empty list, keep "status=success" unchanged!
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------------------------
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If the result content is empty then the filter is expected to respond
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with a "success" status and a flush packet to signal the empty content.
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------------------------
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packet: git< status=success
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packet: git< 0000
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packet: git< 0000 # empty content!
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packet: git< 0000 # empty list, keep "status=success" unchanged!
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------------------------
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In case the filter cannot or does not want to process the content,
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it is expected to respond with an "error" status.
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------------------------
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packet: git< status=error
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packet: git< 0000
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------------------------
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If the filter experiences an error during processing, then it can
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send the status "error" after the content was (partially or
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completely) sent.
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------------------------
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packet: git< status=success
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packet: git< 0000
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packet: git< HALF_WRITTEN_ERRONEOUS_CONTENT
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packet: git< 0000
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packet: git< status=error
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packet: git< 0000
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------------------------
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In case the filter cannot or does not want to process the content
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as well as any future content for the lifetime of the Git process,
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then it is expected to respond with an "abort" status at any point
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in the protocol.
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------------------------
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packet: git< status=abort
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packet: git< 0000
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------------------------
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Git neither stops nor restarts the filter process in case the
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"error"/"abort" status is set. However, Git sets its exit code
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according to the `filter.<driver>.required` flag, mimicking the
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behavior of the `filter.<driver>.clean` / `filter.<driver>.smudge`
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mechanism.
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If the filter dies during the communication or does not adhere to
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the protocol then Git will stop the filter process and restart it
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with the next file that needs to be processed. Depending on the
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`filter.<driver>.required` flag Git will interpret that as error.
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After the filter has processed a blob it is expected to wait for
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the next "key=value" list containing a command. Git will close
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the command pipe on exit. The filter is expected to detect EOF
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and exit gracefully on its own. Git will wait until the filter
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process has stopped.
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A long running filter demo implementation can be found in
|
|
`contrib/long-running-filter/example.pl` located in the Git
|
|
core repository. If you develop your own long running filter
|
|
process then the `GIT_TRACE_PACKET` environment variables can be
|
|
very helpful for debugging (see linkgit:git[1]).
|
|
|
|
Please note that you cannot use an existing `filter.<driver>.clean`
|
|
or `filter.<driver>.smudge` command with `filter.<driver>.process`
|
|
because the former two use a different inter process communication
|
|
protocol than the latter one.
|
|
|
|
|
|
Interaction between checkin/checkout attributes
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
In the check-in codepath, the worktree file is first converted
|
|
with `filter` driver (if specified and corresponding driver
|
|
defined), then the result is processed with `ident` (if
|
|
specified), and then finally with `text` (again, if specified
|
|
and applicable).
|
|
|
|
In the check-out codepath, the blob content is first converted
|
|
with `text`, and then `ident` and fed to `filter`.
|
|
|
|
|
|
Merging branches with differing checkin/checkout attributes
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
If you have added attributes to a file that cause the canonical
|
|
repository format for that file to change, such as adding a
|
|
clean/smudge filter or text/eol/ident attributes, merging anything
|
|
where the attribute is not in place would normally cause merge
|
|
conflicts.
|
|
|
|
To prevent these unnecessary merge conflicts, Git can be told to run a
|
|
virtual check-out and check-in of all three stages of a file when
|
|
resolving a three-way merge by setting the `merge.renormalize`
|
|
configuration variable. This prevents changes caused by check-in
|
|
conversion from causing spurious merge conflicts when a converted file
|
|
is merged with an unconverted file.
|
|
|
|
As long as a "smudge->clean" results in the same output as a "clean"
|
|
even on files that are already smudged, this strategy will
|
|
automatically resolve all filter-related conflicts. Filters that do
|
|
not act in this way may cause additional merge conflicts that must be
|
|
resolved manually.
|
|
|
|
|
|
Generating diff text
|
|
~~~~~~~~~~~~~~~~~~~~
|
|
|
|
`diff`
|
|
^^^^^^
|
|
|
|
The attribute `diff` affects how Git generates diffs for particular
|
|
files. It can tell Git whether to generate a textual patch for the path
|
|
or to treat the path as a binary file. It can also affect what line is
|
|
shown on the hunk header `@@ -k,l +n,m @@` line, tell Git to use an
|
|
external command to generate the diff, or ask Git to convert binary
|
|
files to a text format before generating the diff.
|
|
|
|
Set::
|
|
|
|
A path to which the `diff` attribute is set is treated
|
|
as text, even when they contain byte values that
|
|
normally never appear in text files, such as NUL.
|
|
|
|
Unset::
|
|
|
|
A path to which the `diff` attribute is unset will
|
|
generate `Binary files differ` (or a binary patch, if
|
|
binary patches are enabled).
|
|
|
|
Unspecified::
|
|
|
|
A path to which the `diff` attribute is unspecified
|
|
first gets its contents inspected, and if it looks like
|
|
text and is smaller than core.bigFileThreshold, it is treated
|
|
as text. Otherwise it would generate `Binary files differ`.
|
|
|
|
String::
|
|
|
|
Diff is shown using the specified diff driver. Each driver may
|
|
specify one or more options, as described in the following
|
|
section. The options for the diff driver "foo" are defined
|
|
by the configuration variables in the "diff.foo" section of the
|
|
Git config file.
|
|
|
|
|
|
Defining an external diff driver
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
The definition of a diff driver is done in `gitconfig`, not
|
|
`gitattributes` file, so strictly speaking this manual page is a
|
|
wrong place to talk about it. However...
|
|
|
|
To define an external diff driver `jcdiff`, add a section to your
|
|
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
|
|
|
|
----------------------------------------------------------------
|
|
[diff "jcdiff"]
|
|
command = j-c-diff
|
|
----------------------------------------------------------------
|
|
|
|
When Git needs to show you a diff for the path with `diff`
|
|
attribute set to `jcdiff`, it calls the command you specified
|
|
with the above configuration, i.e. `j-c-diff`, with 7
|
|
parameters, just like `GIT_EXTERNAL_DIFF` program is called.
|
|
See linkgit:git[1] for details.
|
|
|
|
|
|
Defining a custom hunk-header
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Each group of changes (called a "hunk") in the textual diff output
|
|
is prefixed with a line of the form:
|
|
|
|
@@ -k,l +n,m @@ TEXT
|
|
|
|
This is called a 'hunk header'. The "TEXT" portion is by default a line
|
|
that begins with an alphabet, an underscore or a dollar sign; this
|
|
matches what GNU 'diff -p' output uses. This default selection however
|
|
is not suited for some contents, and you can use a customized pattern
|
|
to make a selection.
|
|
|
|
First, in .gitattributes, you would assign the `diff` attribute
|
|
for paths.
|
|
|
|
------------------------
|
|
*.tex diff=tex
|
|
------------------------
|
|
|
|
Then, you would define a "diff.tex.xfuncname" configuration to
|
|
specify a regular expression that matches a line that you would
|
|
want to appear as the hunk header "TEXT". Add a section to your
|
|
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
|
|
|
|
------------------------
|
|
[diff "tex"]
|
|
xfuncname = "^(\\\\(sub)*section\\{.*)$"
|
|
------------------------
|
|
|
|
Note. A single level of backslashes are eaten by the
|
|
configuration file parser, so you would need to double the
|
|
backslashes; the pattern above picks a line that begins with a
|
|
backslash, and zero or more occurrences of `sub` followed by
|
|
`section` followed by open brace, to the end of line.
|
|
|
|
There are a few built-in patterns to make this easier, and `tex`
|
|
is one of them, so you do not have to write the above in your
|
|
configuration file (you still need to enable this with the
|
|
attribute mechanism, via `.gitattributes`). The following built in
|
|
patterns are available:
|
|
|
|
- `ada` suitable for source code in the Ada language.
|
|
|
|
- `bibtex` suitable for files with BibTeX coded references.
|
|
|
|
- `cpp` suitable for source code in the C and C++ languages.
|
|
|
|
- `csharp` suitable for source code in the C# language.
|
|
|
|
- `css` suitable for cascading style sheets.
|
|
|
|
- `fortran` suitable for source code in the Fortran language.
|
|
|
|
- `fountain` suitable for Fountain documents.
|
|
|
|
- `html` suitable for HTML/XHTML documents.
|
|
|
|
- `java` suitable for source code in the Java language.
|
|
|
|
- `matlab` suitable for source code in the MATLAB language.
|
|
|
|
- `objc` suitable for source code in the Objective-C language.
|
|
|
|
- `pascal` suitable for source code in the Pascal/Delphi language.
|
|
|
|
- `perl` suitable for source code in the Perl language.
|
|
|
|
- `php` suitable for source code in the PHP language.
|
|
|
|
- `python` suitable for source code in the Python language.
|
|
|
|
- `ruby` suitable for source code in the Ruby language.
|
|
|
|
- `tex` suitable for source code for LaTeX documents.
|
|
|
|
|
|
Customizing word diff
|
|
^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
You can customize the rules that `git diff --word-diff` uses to
|
|
split words in a line, by specifying an appropriate regular expression
|
|
in the "diff.*.wordRegex" configuration variable. For example, in TeX
|
|
a backslash followed by a sequence of letters forms a command, but
|
|
several such commands can be run together without intervening
|
|
whitespace. To separate them, use a regular expression in your
|
|
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
|
|
|
|
------------------------
|
|
[diff "tex"]
|
|
wordRegex = "\\\\[a-zA-Z]+|[{}]|\\\\.|[^\\{}[:space:]]+"
|
|
------------------------
|
|
|
|
A built-in pattern is provided for all languages listed in the
|
|
previous section.
|
|
|
|
|
|
Performing text diffs of binary files
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Sometimes it is desirable to see the diff of a text-converted
|
|
version of some binary files. For example, a word processor
|
|
document can be converted to an ASCII text representation, and
|
|
the diff of the text shown. Even though this conversion loses
|
|
some information, the resulting diff is useful for human
|
|
viewing (but cannot be applied directly).
|
|
|
|
The `textconv` config option is used to define a program for
|
|
performing such a conversion. The program should take a single
|
|
argument, the name of a file to convert, and produce the
|
|
resulting text on stdout.
|
|
|
|
For example, to show the diff of the exif information of a
|
|
file instead of the binary information (assuming you have the
|
|
exif tool installed), add the following section to your
|
|
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file):
|
|
|
|
------------------------
|
|
[diff "jpg"]
|
|
textconv = exif
|
|
------------------------
|
|
|
|
NOTE: The text conversion is generally a one-way conversion;
|
|
in this example, we lose the actual image contents and focus
|
|
just on the text data. This means that diffs generated by
|
|
textconv are _not_ suitable for applying. For this reason,
|
|
only `git diff` and the `git log` family of commands (i.e.,
|
|
log, whatchanged, show) will perform text conversion. `git
|
|
format-patch` will never generate this output. If you want to
|
|
send somebody a text-converted diff of a binary file (e.g.,
|
|
because it quickly conveys the changes you have made), you
|
|
should generate it separately and send it as a comment _in
|
|
addition to_ the usual binary diff that you might send.
|
|
|
|
Because text conversion can be slow, especially when doing a
|
|
large number of them with `git log -p`, Git provides a mechanism
|
|
to cache the output and use it in future diffs. To enable
|
|
caching, set the "cachetextconv" variable in your diff driver's
|
|
config. For example:
|
|
|
|
------------------------
|
|
[diff "jpg"]
|
|
textconv = exif
|
|
cachetextconv = true
|
|
------------------------
|
|
|
|
This will cache the result of running "exif" on each blob
|
|
indefinitely. If you change the textconv config variable for a
|
|
diff driver, Git will automatically invalidate the cache entries
|
|
and re-run the textconv filter. If you want to invalidate the
|
|
cache manually (e.g., because your version of "exif" was updated
|
|
and now produces better output), you can remove the cache
|
|
manually with `git update-ref -d refs/notes/textconv/jpg` (where
|
|
"jpg" is the name of the diff driver, as in the example above).
|
|
|
|
Choosing textconv versus external diff
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
If you want to show differences between binary or specially-formatted
|
|
blobs in your repository, you can choose to use either an external diff
|
|
command, or to use textconv to convert them to a diff-able text format.
|
|
Which method you choose depends on your exact situation.
|
|
|
|
The advantage of using an external diff command is flexibility. You are
|
|
not bound to find line-oriented changes, nor is it necessary for the
|
|
output to resemble unified diff. You are free to locate and report
|
|
changes in the most appropriate way for your data format.
|
|
|
|
A textconv, by comparison, is much more limiting. You provide a
|
|
transformation of the data into a line-oriented text format, and Git
|
|
uses its regular diff tools to generate the output. There are several
|
|
advantages to choosing this method:
|
|
|
|
1. Ease of use. It is often much simpler to write a binary to text
|
|
transformation than it is to perform your own diff. In many cases,
|
|
existing programs can be used as textconv filters (e.g., exif,
|
|
odt2txt).
|
|
|
|
2. Git diff features. By performing only the transformation step
|
|
yourself, you can still utilize many of Git's diff features,
|
|
including colorization, word-diff, and combined diffs for merges.
|
|
|
|
3. Caching. Textconv caching can speed up repeated diffs, such as those
|
|
you might trigger by running `git log -p`.
|
|
|
|
|
|
Marking files as binary
|
|
^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Git usually guesses correctly whether a blob contains text or binary
|
|
data by examining the beginning of the contents. However, sometimes you
|
|
may want to override its decision, either because a blob contains binary
|
|
data later in the file, or because the content, while technically
|
|
composed of text characters, is opaque to a human reader. For example,
|
|
many postscript files contain only ASCII characters, but produce noisy
|
|
and meaningless diffs.
|
|
|
|
The simplest way to mark a file as binary is to unset the diff
|
|
attribute in the `.gitattributes` file:
|
|
|
|
------------------------
|
|
*.ps -diff
|
|
------------------------
|
|
|
|
This will cause Git to generate `Binary files differ` (or a binary
|
|
patch, if binary patches are enabled) instead of a regular diff.
|
|
|
|
However, one may also want to specify other diff driver attributes. For
|
|
example, you might want to use `textconv` to convert postscript files to
|
|
an ASCII representation for human viewing, but otherwise treat them as
|
|
binary files. You cannot specify both `-diff` and `diff=ps` attributes.
|
|
The solution is to use the `diff.*.binary` config option:
|
|
|
|
------------------------
|
|
[diff "ps"]
|
|
textconv = ps2ascii
|
|
binary = true
|
|
------------------------
|
|
|
|
Performing a three-way merge
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
`merge`
|
|
^^^^^^^
|
|
|
|
The attribute `merge` affects how three versions of a file are
|
|
merged when a file-level merge is necessary during `git merge`,
|
|
and other commands such as `git revert` and `git cherry-pick`.
|
|
|
|
Set::
|
|
|
|
Built-in 3-way merge driver is used to merge the
|
|
contents in a way similar to 'merge' command of `RCS`
|
|
suite. This is suitable for ordinary text files.
|
|
|
|
Unset::
|
|
|
|
Take the version from the current branch as the
|
|
tentative merge result, and declare that the merge has
|
|
conflicts. This is suitable for binary files that do
|
|
not have a well-defined merge semantics.
|
|
|
|
Unspecified::
|
|
|
|
By default, this uses the same built-in 3-way merge
|
|
driver as is the case when the `merge` attribute is set.
|
|
However, the `merge.default` configuration variable can name
|
|
different merge driver to be used with paths for which the
|
|
`merge` attribute is unspecified.
|
|
|
|
String::
|
|
|
|
3-way merge is performed using the specified custom
|
|
merge driver. The built-in 3-way merge driver can be
|
|
explicitly specified by asking for "text" driver; the
|
|
built-in "take the current branch" driver can be
|
|
requested with "binary".
|
|
|
|
|
|
Built-in merge drivers
|
|
^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
There are a few built-in low-level merge drivers defined that
|
|
can be asked for via the `merge` attribute.
|
|
|
|
text::
|
|
|
|
Usual 3-way file level merge for text files. Conflicted
|
|
regions are marked with conflict markers `<<<<<<<`,
|
|
`=======` and `>>>>>>>`. The version from your branch
|
|
appears before the `=======` marker, and the version
|
|
from the merged branch appears after the `=======`
|
|
marker.
|
|
|
|
binary::
|
|
|
|
Keep the version from your branch in the work tree, but
|
|
leave the path in the conflicted state for the user to
|
|
sort out.
|
|
|
|
union::
|
|
|
|
Run 3-way file level merge for text files, but take
|
|
lines from both versions, instead of leaving conflict
|
|
markers. This tends to leave the added lines in the
|
|
resulting file in random order and the user should
|
|
verify the result. Do not use this if you do not
|
|
understand the implications.
|
|
|
|
|
|
Defining a custom merge driver
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
The definition of a merge driver is done in the `.git/config`
|
|
file, not in the `gitattributes` file, so strictly speaking this
|
|
manual page is a wrong place to talk about it. However...
|
|
|
|
To define a custom merge driver `filfre`, add a section to your
|
|
`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
|
|
|
|
----------------------------------------------------------------
|
|
[merge "filfre"]
|
|
name = feel-free merge driver
|
|
driver = filfre %O %A %B %L %P
|
|
recursive = binary
|
|
----------------------------------------------------------------
|
|
|
|
The `merge.*.name` variable gives the driver a human-readable
|
|
name.
|
|
|
|
The `merge.*.driver` variable's value is used to construct a
|
|
command to run to merge ancestor's version (`%O`), current
|
|
version (`%A`) and the other branches' version (`%B`). These
|
|
three tokens are replaced with the names of temporary files that
|
|
hold the contents of these versions when the command line is
|
|
built. Additionally, %L will be replaced with the conflict marker
|
|
size (see below).
|
|
|
|
The merge driver is expected to leave the result of the merge in
|
|
the file named with `%A` by overwriting it, and exit with zero
|
|
status if it managed to merge them cleanly, or non-zero if there
|
|
were conflicts.
|
|
|
|
The `merge.*.recursive` variable specifies what other merge
|
|
driver to use when the merge driver is called for an internal
|
|
merge between common ancestors, when there are more than one.
|
|
When left unspecified, the driver itself is used for both
|
|
internal merge and the final merge.
|
|
|
|
The merge driver can learn the pathname in which the merged result
|
|
will be stored via placeholder `%P`.
|
|
|
|
|
|
`conflict-marker-size`
|
|
^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
This attribute controls the length of conflict markers left in
|
|
the work tree file during a conflicted merge. Only setting to
|
|
the value to a positive integer has any meaningful effect.
|
|
|
|
For example, this line in `.gitattributes` can be used to tell the merge
|
|
machinery to leave much longer (instead of the usual 7-character-long)
|
|
conflict markers when merging the file `Documentation/git-merge.txt`
|
|
results in a conflict.
|
|
|
|
------------------------
|
|
Documentation/git-merge.txt conflict-marker-size=32
|
|
------------------------
|
|
|
|
|
|
Checking whitespace errors
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
`whitespace`
|
|
^^^^^^^^^^^^
|
|
|
|
The `core.whitespace` configuration variable allows you to define what
|
|
'diff' and 'apply' should consider whitespace errors for all paths in
|
|
the project (See linkgit:git-config[1]). This attribute gives you finer
|
|
control per path.
|
|
|
|
Set::
|
|
|
|
Notice all types of potential whitespace errors known to Git.
|
|
The tab width is taken from the value of the `core.whitespace`
|
|
configuration variable.
|
|
|
|
Unset::
|
|
|
|
Do not notice anything as error.
|
|
|
|
Unspecified::
|
|
|
|
Use the value of the `core.whitespace` configuration variable to
|
|
decide what to notice as error.
|
|
|
|
String::
|
|
|
|
Specify a comma separate list of common whitespace problems to
|
|
notice in the same format as the `core.whitespace` configuration
|
|
variable.
|
|
|
|
|
|
Creating an archive
|
|
~~~~~~~~~~~~~~~~~~~
|
|
|
|
`export-ignore`
|
|
^^^^^^^^^^^^^^^
|
|
|
|
Files and directories with the attribute `export-ignore` won't be added to
|
|
archive files.
|
|
|
|
`export-subst`
|
|
^^^^^^^^^^^^^^
|
|
|
|
If the attribute `export-subst` is set for a file then Git will expand
|
|
several placeholders when adding this file to an archive. The
|
|
expansion depends on the availability of a commit ID, i.e., if
|
|
linkgit:git-archive[1] has been given a tree instead of a commit or a
|
|
tag then no replacement will be done. The placeholders are the same
|
|
as those for the option `--pretty=format:` of linkgit:git-log[1],
|
|
except that they need to be wrapped like this: `$Format:PLACEHOLDERS$`
|
|
in the file. E.g. the string `$Format:%H$` will be replaced by the
|
|
commit hash.
|
|
|
|
|
|
Packing objects
|
|
~~~~~~~~~~~~~~~
|
|
|
|
`delta`
|
|
^^^^^^^
|
|
|
|
Delta compression will not be attempted for blobs for paths with the
|
|
attribute `delta` set to false.
|
|
|
|
|
|
Viewing files in GUI tools
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
`encoding`
|
|
^^^^^^^^^^
|
|
|
|
The value of this attribute specifies the character encoding that should
|
|
be used by GUI tools (e.g. linkgit:gitk[1] and linkgit:git-gui[1]) to
|
|
display the contents of the relevant file. Note that due to performance
|
|
considerations linkgit:gitk[1] does not use this attribute unless you
|
|
manually enable per-file encodings in its options.
|
|
|
|
If this attribute is not set or has an invalid value, the value of the
|
|
`gui.encoding` configuration variable is used instead
|
|
(See linkgit:git-config[1]).
|
|
|
|
|
|
USING MACRO ATTRIBUTES
|
|
----------------------
|
|
|
|
You do not want any end-of-line conversions applied to, nor textual diffs
|
|
produced for, any binary file you track. You would need to specify e.g.
|
|
|
|
------------
|
|
*.jpg -text -diff
|
|
------------
|
|
|
|
but that may become cumbersome, when you have many attributes. Using
|
|
macro attributes, you can define an attribute that, when set, also
|
|
sets or unsets a number of other attributes at the same time. The
|
|
system knows a built-in macro attribute, `binary`:
|
|
|
|
------------
|
|
*.jpg binary
|
|
------------
|
|
|
|
Setting the "binary" attribute also unsets the "text" and "diff"
|
|
attributes as above. Note that macro attributes can only be "Set",
|
|
though setting one might have the effect of setting or unsetting other
|
|
attributes or even returning other attributes to the "Unspecified"
|
|
state.
|
|
|
|
|
|
DEFINING MACRO ATTRIBUTES
|
|
-------------------------
|
|
|
|
Custom macro attributes can be defined only in top-level gitattributes
|
|
files (`$GIT_DIR/info/attributes`, the `.gitattributes` file at the
|
|
top level of the working tree, or the global or system-wide
|
|
gitattributes files), not in `.gitattributes` files in working tree
|
|
subdirectories. The built-in macro attribute "binary" is equivalent
|
|
to:
|
|
|
|
------------
|
|
[attr]binary -diff -merge -text
|
|
------------
|
|
|
|
|
|
EXAMPLE
|
|
-------
|
|
|
|
If you have these three `gitattributes` file:
|
|
|
|
----------------------------------------------------------------
|
|
(in $GIT_DIR/info/attributes)
|
|
|
|
a* foo !bar -baz
|
|
|
|
(in .gitattributes)
|
|
abc foo bar baz
|
|
|
|
(in t/.gitattributes)
|
|
ab* merge=filfre
|
|
abc -foo -bar
|
|
*.c frotz
|
|
----------------------------------------------------------------
|
|
|
|
the attributes given to path `t/abc` are computed as follows:
|
|
|
|
1. By examining `t/.gitattributes` (which is in the same
|
|
directory as the path in question), Git finds that the first
|
|
line matches. `merge` attribute is set. It also finds that
|
|
the second line matches, and attributes `foo` and `bar`
|
|
are unset.
|
|
|
|
2. Then it examines `.gitattributes` (which is in the parent
|
|
directory), and finds that the first line matches, but
|
|
`t/.gitattributes` file already decided how `merge`, `foo`
|
|
and `bar` attributes should be given to this path, so it
|
|
leaves `foo` and `bar` unset. Attribute `baz` is set.
|
|
|
|
3. Finally it examines `$GIT_DIR/info/attributes`. This file
|
|
is used to override the in-tree settings. The first line is
|
|
a match, and `foo` is set, `bar` is reverted to unspecified
|
|
state, and `baz` is unset.
|
|
|
|
As the result, the attributes assignment to `t/abc` becomes:
|
|
|
|
----------------------------------------------------------------
|
|
foo set to true
|
|
bar unspecified
|
|
baz set to false
|
|
merge set to string value "filfre"
|
|
frotz unspecified
|
|
----------------------------------------------------------------
|
|
|
|
|
|
SEE ALSO
|
|
--------
|
|
linkgit:git-check-attr[1].
|
|
|
|
GIT
|
|
---
|
|
Part of the linkgit:git[1] suite
|