The `struct image` uses a character array to track the pre- or postimage
of a patch operation. This has multiple downsides:
- It is somewhat hard to track memory ownership. In fact, we have
several memory leaks in git-apply(1) because we do not (and cannot
easily) free the buffer in all situations.
- We have to reinvent the wheel and manually implement a lot of
functionality that would already be provided by `struct strbuf`.
- We have to carefully track whether `update_pre_post_images()` can do
an in-place update of the postimage or whether it has to allocate a
new buffer for it.
This is all rather cumbersome, and especially `update_pre_post_images()`
is really hard to understand as a consequence even though what it is
doing is rather trivial.
Refactor the code to use a `struct strbuf` instead, addressing all of
the above. Like this we can easily perform in-place updates in all
situations, the logic to perform those updates becomes way simpler and
the lifetime of the buffer becomes a ton easier to track.
This refactoring also plugs some leaking buffers as a side effect.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some diff implementations don't report missing newlines at the end of
files. Applying such a patch can cause a newline character to be
added inadvertently. The option --inaccurate-eof of git apply can be
used to remove trailing newlines if needed.
apply_one_fragment() cuts it off from the buffers for preimage and
postimage. Before it does, it builds an array with the lengths of each
line for both. Make sure to update the length of the last line in
these line info structures as well to keep them consistent with their
respective buffer.
Without this fix the added test fails; git apply dies and reports:
fatal: BUG: caller miscounted postlen: asked 1, orig = 1, used = 2
That sanity check is only called if whitespace changes are ignored.
Reported-by: Mahmoud Al-Qudsi <mqudsi@neosmart.net>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The fuzzy_matchlines() function is used when attempting to resurrect
a patch that is whitespace-damaged, or when applying a patch that
was produced against an old codebase to the codebase after
indentation change.
The patch may want to change a line "a_bc" ("_" is used throught
this description for a whitespace to make it stand out) in the
original into something else, and we may not find "a_bc" in the
current source, but there may be "a__bc" (two spaces instead of one
the whitespace-damaged patch claims to expect). By ignoring the
amount of whitespaces, it forces "git apply" to consider that "a_bc"
in the broken patch meant to refer to "a__bc" in reality.
However, the implementation special cases a run of whitespaces at
the beginning of a line and makes "abc" match "_abc", even though a
whitespace in the middle of string never matches a 0-width gap,
e.g. "a_bc" does not match "abc". A run of whitespace at the end of
one string does not match a 0-width end of line on the other line,
either, e.g. "abc_" does not match "abc".
Fix this inconsistency by making the code skip leading whitespaces
only when both strings begin with a whitespace. This makes the
option mean the same as the option of the same name in "diff" and
"git diff".
Note that I am not sure if anybody sane should use this option in
the first place. The fuzzy match logic may be able to find the
original line that the patch author may have meant to touch because
it does not fully trust what the original lines say (i.e. context
lines prefixed by " " and old lines prefixed by "-" does not have to
exactly match the contents the patch is applied to). There is no
reason for us to trust what the replacement lines (i.e. new lines
prefixed by "+") say, either, but with this option enabled, we end
up copying these new lines with suspicious whitespace distributions
literally into the patched result. But as long as we keep it, we
should make it do its insane thing consistently.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is needed to allow test suite to run against a standard
install bin directory instead of GIT_EXEC_PATH.
Signed-off-by: Matthew Ogilvie <mmogilvi_git@miniinfo.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Introduce --ignore-whitespace option and corresponding config bool to
ignore whitespace differences while applying patches, akin to the
'patch' program.
'git am', 'git rebase' and the bash git completion are made aware of
this option.
Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
