Commit Graph

13 Commits

Author SHA1 Message Date
Johannes Schindelin
7723436149 stash -p: (partially) fix bug concerning split hunks
When trying to stash part of the worktree changes by splitting a hunk
and then only partially accepting the split bits and pieces, the user
is presented with a rather cryptic error:

	error: patch failed: <file>:<line>
	error: test: patch does not apply
	Cannot remove worktree changes

and the command would fail to stash the desired parts of the worktree
changes (even if the `stash` ref was actually updated correctly).

We even have a test case demonstrating that failure, carrying it for
four years already.

The explanation: when splitting a hunk, the changed lines are no longer
separated by more than 3 lines (which is the amount of context lines
Git's diffs use by default), but less than that. So when staging only
part of the diff hunk for stashing, the resulting diff that we want to
apply to the worktree in reverse will contain those changes to be
dropped surrounded by three context lines, but since the diff is
relative to HEAD rather than to the worktree, these context lines will
not match.

Example time. Let's assume that the file README contains these lines:

	We
	the
	people

and the worktree added some lines so that it contains these lines
instead:

	We
	are
	the
	kind
	people

and the user tries to stash the line containing "are", then the command
will internally stage this line to a temporary index file and try to
revert the diff between HEAD and that index file. The diff hunk that
`git stash` tries to revert will look somewhat like this:

	@@ -1776,3 +1776,4
	 We
	+are
	 the
	 people

It is obvious, now, that the trailing context lines overlap with the
part of the original diff hunk that the user did *not* want to stash.

Keeping in mind that context lines in diffs serve the primary purpose of
finding the exact location when the diff does not apply precisely (but
when the exact line number in the file to be patched differs from the
line number indicated in the diff), we work around this by reducing the
amount of context lines: the diff was just generated.

Note: this is not a *full* fix for the issue. Just as demonstrated in
t3701's 'add -p works with pathological context lines' test case, there
are ambiguities in the diff format. It is very rare in practice, of
course, to encounter such repeated lines.

The full solution for such cases would be to replace the approach of
generating a diff from the stash and then applying it in reverse by
emulating `git revert` (i.e. doing a 3-way merge). However, in `git
stash -p` it would not apply to `HEAD` but instead to the worktree,
which makes this non-trivial to implement as long as we also maintain a
scripted version of `add -i`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-08 12:17:59 -07:00
Johannes Schindelin
121c0d4151 t3904: fix incorrect demonstration of a bug
In 7e9e048661 (stash -p: demonstrate failure of split with mixed y/n,
2015-04-16), a regression test for a known breakage that was added to
the test script `t3904-stash-patch.sh` that demonstrated that splitting
a hunk and trying to stash only part of that split hunk fails (but
shouldn't).

As expected, it still fails, but for the wrong reason: once the bug is
fixed, we would expect stderr to show nothing, yet the regression test
expects stderr to show something.

Let's fix that by telling that regression test case to expect nothing to
be printed to stderr.

While at it, also drop the obvious left-over from debugging where the
regression test did not mind `git stash -p` to return a non-zero exit
status.

Of course, the regression test still fails, but this time for the
correct reason.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-08 12:17:58 -07:00
Eric Sunshine
0590ff26c4 t: use test_write_lines() instead of series of 'echo' commands
These tests employ a noisy subshell (with missing &&-chain) to feed
input into Git commands or files:

    (echo a; echo b; echo c) | git some-command ...

Simplify by taking advantage of test_write_lines():

    test_write_lines a b c | git some-command ...

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-03 12:38:04 -07:00
Thomas Gummerer
869fb8f729 stash: pass the pathspec argument to git reset
For "git stash -p --no-keep-index", the pathspec argument is currently
not passed to "git reset".  This means that changes that are staged but
that are excluded from the pathspec still get unstaged by git stash -p.

Make sure that doesn't happen by passing the pathspec argument to the
git reset in question, bringing the behaviour in line with "git stash --
<pathspec>".

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-22 14:55:55 -07:00
Matthieu Moy
7e9e048661 stash -p: demonstrate failure of split with mixed y/n
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-16 14:14:12 -07:00
Matthieu Moy
798a5b03fb t3904-stash-patch: factor PERL prereq at the top of the file
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-16 14:14:11 -07:00
Matthieu Moy
470b11e805 t3904-stash-patch: fix test description
The old description is rather clearly a wrong cut-and-paste from
t2016-checkout-patch.sh.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-16 14:14:11 -07:00
Jonathon Mah
44df2e2970 stash: Don't fail if work dir contains file named 'HEAD'
When performing a plain "git stash" (without --patch), git-diff would fail
with "fatal: ambiguous argument 'HEAD': both revision and filename". The
output was piped into git-update-index, masking the failed exit status.
The output is now sent to a temporary file (which is cleaned up by
existing code), and the exit status is checked. The "HEAD" arg to the
git-diff invocation has been disambiguated too, of course.

In patch mode, "git stash -p" would fail harmlessly, leaving the working
dir untouched. Interactive adding is fine, but the resulting tree was
diffed with an ambiguous 'HEAD' argument.

Use >foo (no space) when redirecting output.

In t3904, checks and operations on each file are in the order they'll
appear when interactively staging.

In t3905, fix a bug in "stash save --include-untracked -q is quiet": The
redirected stdout file was considered untracked, and so was removed from
the working directory. Use test path helper functions where appropriate.

Signed-off-by: Jonathon Mah <me@JonathonMah.com>
Acked-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-01 01:11:56 -08:00
Dan McGee
3a243f7024 stash: ensure --no-keep-index and --patch can be used in any order
Don't assume one comes after the other on the command line. Use a
three-state variable to track and check its value accordingly.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-07 15:54:04 -07:00
Dan McGee
21ec98a75d stash: add two more tests for --no-keep-index
One of these passes just fine; the other one exposes a problem where
command line flag order matters for --no-keep-index and --patch
interaction.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-07 15:53:02 -07:00
Jonathan Nieder
a48fcd8369 tests: add missing &&
Breaks in a test assertion's && chain can potentially hide
failures from earlier commands in the chain.

Commands intended to fail should be marked with !, test_must_fail, or
test_might_fail.  The examples in this patch do not require that.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-09 11:59:49 -08:00
Ævar Arnfjörð Bjarmason
f2f7b6a550 lib-patch-mode tests: change from skip_all=* to prereq skip
Change this test to skip test with test prerequisites, and to do setup
work in tests. This improves the skipped statistics on platforms where
the test isn't run.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-18 12:43:23 -07:00
Thomas Rast
dda1f2a5c3 Implement 'git stash save --patch'
This adds a hunk-based mode to git-stash.  You can select hunks from
the difference between HEAD and worktree, and git-stash will build a
stash that reflects these changes.  The index state of the stash is
the same as your current index, and we also let --patch imply
--keep-index.

Note that because the selected hunks are rolled back from the worktree
but not the index, the resulting state may appear somewhat confusing
if you had also staged these changes.  This is not entirely
satisfactory, but due to the way stashes are applied, other solutions
would require a change to the stash format.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-08-15 15:19:31 -07:00