The "-z" format is all about machine parsability, but showing renamed
paths as "common/{a => b}/suffix" makes it impossible.  The scripts would
never have successfully parsed "--numstat -z -M" in the old format.
This fixes the output format in a (hopefully minimally) backward
incompatible way.
 * The output without -z is not changed.  This has given a good way for
   humans to view added and deleted lines separately, and showing the
   path in combined, shorter way would preserve readability.
 * The output with -z is unchanged for paths that do not involve renames.
   Existing scripts that do not pass -M/-C are not affected at all.
 * The output with -z for a renamed path is shown in a format that can
   easily be distinguished from an unrenamed path.
This is based on Jakub Narebski's patch.  Bugs and documentation typos
are mine.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
		
	
		
			
				
	
	
		
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			148 lines
		
	
	
		
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			Plaintext
		
	
	
	
	
	
The output format from "git-diff-index", "git-diff-tree",
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"git-diff-files" and "git diff --raw" are very similar.
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These commands all compare two sets of things; what is
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compared differs:
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git-diff-index <tree-ish>::
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        compares the <tree-ish> and the files on the filesystem.
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git-diff-index --cached <tree-ish>::
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        compares the <tree-ish> and the index.
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git-diff-tree [-r] <tree-ish-1> <tree-ish-2> [<pattern>...]::
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        compares the trees named by the two arguments.
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git-diff-files [<pattern>...]::
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        compares the index and the files on the filesystem.
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An output line is formatted this way:
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------------------------------------------------
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in-place edit  :100644 100644 bcd1234... 0123456... M file0
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copy-edit      :100644 100644 abcd123... 1234567... C68 file1 file2
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rename-edit    :100644 100644 abcd123... 1234567... R86 file1 file3
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create         :000000 100644 0000000... 1234567... A file4
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delete         :100644 000000 1234567... 0000000... D file5
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unmerged       :000000 000000 0000000... 0000000... U file6
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------------------------------------------------
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That is, from the left to the right:
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. a colon.
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. mode for "src"; 000000 if creation or unmerged.
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. a space.
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. mode for "dst"; 000000 if deletion or unmerged.
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. a space.
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. sha1 for "src"; 0\{40\} if creation or unmerged.
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. a space.
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. sha1 for "dst"; 0\{40\} if creation, unmerged or "look at work tree".
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. a space.
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. status, followed by optional "score" number.
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. a tab or a NUL when '-z' option is used.
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. path for "src"
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. a tab or a NUL when '-z' option is used; only exists for C or R.
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. path for "dst"; only exists for C or R.
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. an LF or a NUL when '-z' option is used, to terminate the record.
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<sha1> is shown as all 0's if a file is new on the filesystem
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and it is out of sync with the index.
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Example:
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------------------------------------------------
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:100644 100644 5be4a4...... 000000...... M file.c
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------------------------------------------------
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When `-z` option is not used, TAB, LF, and backslash characters
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in pathnames are represented as `\t`, `\n`, and `\\`,
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respectively.
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diff format for merges
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----------------------
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"git-diff-tree", "git-diff-files" and "git-diff --raw"
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can take '-c' or '--cc' option
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to generate diff output also for merge commits.  The output differs
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from the format described above in the following way:
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. there is a colon for each parent
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. there are more "src" modes and "src" sha1
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. status is concatenated status characters for each parent
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. no optional "score" number
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. single path, only for "dst"
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Example:
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------------------------------------------------
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::100644 100644 100644 fabadb8... cc95eb0... 4866510... MM	describe.c
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------------------------------------------------
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Note that 'combined diff' lists only files which were modified from
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all parents.
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include::diff-generate-patch.txt[]
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other diff formats
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------------------
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The `--summary` option describes newly added, deleted, renamed and
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copied files.  The `--stat` option adds diffstat(1) graph to the
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output.  These options can be combined with other options, such as
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`-p`, and are meant for human consumption.
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When showing a change that involves a rename or a copy, `--stat` output
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formats the pathnames compactly by combining common prefix and suffix of
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the pathnames.  For example, a change that moves `arch/i386/Makefile` to
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`arch/x86/Makefile` while modifying 4 lines will be shown like this:
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------------------------------------
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arch/{i386 => x86}/Makefile    |   4 +--
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------------------------------------
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The `--numstat` option gives the diffstat(1) information but is designed
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for easier machine consumption.  An entry in `--numstat` output looks
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like this:
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----------------------------------------
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1	2	README
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3	1	arch/{i386 => x86}/Makefile
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----------------------------------------
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That is, from left to right:
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. the number of added lines;
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. a tab;
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. the number of deleted lines;
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. a tab;
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. pathname (possibly with rename/copy information);
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. a newline.
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When `-z` output option is in effect, the output is formatted this way:
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----------------------------------------
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1	2	README NUL
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3	1	NUL arch/i386/Makefile NUL arch/x86/Makefile NUL
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----------------------------------------
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That is:
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. the number of added lines;
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. a tab;
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. the number of deleted lines;
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. a tab;
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. a NUL (only exists if renamed/copied);
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. pathname in preimage;
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. a NUL (only exists if renamed/copied);
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. pathname in postimage (only exists if renamed/copied);
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. a NUL.
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The extra `NUL` before the preimage path in renamed case is to allow
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scripts that read the output to tell if the current record being read is
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a single-path record or a rename/copy record without reading ahead.
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After reading added and deleted lines, reading up to `NUL` would yield
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the pathname, but if that is `NUL`, the record will show two paths.
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