Commit Graph

6119 Commits

Author SHA1 Message Date
Junio C Hamano
3be9ac7e56 Merge branch 'jc/check-ref-format-oor' into maint
"git check-ref-format --branch @{-1}" bit a "BUG()" when run
outside a repository for obvious reasons; clarify the documentation
and make sure we do not even try to expand the at-mark magic in
such a case, but still call the validation logic for branch names.

* jc/check-ref-format-oor:
  check-ref-format doc: --branch validates and expands <branch>
  check-ref-format --branch: strip refs/heads/ using skip_prefix
  check-ref-format --branch: do not expand @{...} outside repository
2017-11-15 12:04:57 +09:00
Junio C Hamano
fd7c38c793 Merge branch 'bw/grep-recurse-submodules' into maint
A broken access to object databases in recent update to "git grep
--recurse-submodules" has been fixed.

* bw/grep-recurse-submodules:
  grep: take the read-lock when adding a submodule
2017-11-15 12:04:55 +09:00
Junio C Hamano
a9749b0b78 Merge branch 'ao/check-resolve-ref-unsafe-result' into maint
"git commit", after making a commit, did not check for errors when
asking on what branch it made the commit, which has been correted.

* ao/check-resolve-ref-unsafe-result:
  commit: check result of resolve_ref_unsafe
2017-11-15 12:04:53 +09:00
Martin Ågren
9560e6245a grep: take the read-lock when adding a submodule
With --recurse-submodules, we add each submodule that we encounter to
the list of alternate object databases. With threading, our changes to
the list are not protected against races. Indeed, ThreadSanitizer
reports a race when we call `add_to_alternates_memory()` around the same
time that another thread is reading in the list through
`read_sha1_file()`.

Take the grep read-lock while adding the submodule. The lock is used to
serialize uses of non-thread-safe parts of Git's API, including
`read_sha1_file()`.

Helped-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Acked-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-02 10:58:08 +09:00
Jeff King
752848df0f remote: handle broken symrefs
It's possible for resolve_ref_unsafe() to return NULL with a
REF_ISSYMREF flag if a symref points to a broken ref.  In
this case, the read_remote_branches() function will segfault
passing the name to xstrdup().

This is hard to trigger in practice, since this function is
used as a callback to for_each_ref(), which will skip broken
refs in the first place (so it would have to be broken
racily, or for us to see a transient filesystem error).

If we see such a racy broken outcome let's treat it as "not
a symref". This is exactly the same thing that would happen
in the non-racy case (our function would not be called at
all, as for_each_ref would skip the broken symref).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-21 21:29:02 +09:00
Andrey Okoshkin
c26de08370 commit: check result of resolve_ref_unsafe
Add check of the resolved HEAD reference while printing of a commit summary.
resolve_ref_unsafe() may return NULL pointer if underlying calls of lstat() or
open() fail in files_read_raw_ref().
Such situation can be caused by race: file becomes inaccessible to this moment.

Signed-off-by: Andrey Okoshkin <a.okoshkin@samsung.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-21 21:23:44 +09:00
Junio C Hamano
e3e3c6a43e Merge branch 'jk/ref-filter-colors-fix' into maint
This is the "theoretically more correct" approach of simply
stepping back to the state before plumbing commands started paying
attention to "color.ui" configuration variable.

* jk/ref-filter-colors-fix:
  tag: respect color.ui config
  Revert "color: check color.ui in git_default_config()"
  Revert "t6006: drop "always" color config tests"
  Revert "color: make "always" the same as "auto" in config"
  color: make "always" the same as "auto" in config
  provide --color option for all ref-filter users
  t3205: use --color instead of color.branch=always
  t3203: drop "always" color test
  t6006: drop "always" color config tests
  t7502: use diff.noprefix for --verbose test
  t7508: use test_terminal for color output
  t3701: use test-terminal to collect color output
  t4015: prefer --color to -c color.diff=always
  test-terminal: set TERM=vt100
2017-10-18 14:20:43 +09:00
Junio C Hamano
a116022e03 Merge branch 'sb/branch-avoid-repeated-strbuf-release' into maint
* sb/branch-avoid-repeated-strbuf-release:
  branch: reset instead of release a strbuf
2017-10-18 14:19:14 +09:00
Junio C Hamano
0445bd7b55 Merge branch 'mg/timestamp-t-fix' into maint
A mismerge fix.

* mg/timestamp-t-fix:
  name-rev: change ULONG_MAX to TIME_MAX
2017-10-18 14:19:09 +09:00
Junio C Hamano
16ba0f44c0 Merge branch 'jk/diff-blob' into maint
"git cat-file --textconv" started segfaulting recently, which
has been corrected.

* jk/diff-blob:
  cat-file: handle NULL object_context.path
2017-10-18 14:19:01 +09:00
Junio C Hamano
501ec0dad3 Merge branch 'jk/describe-omit-some-refs' into maint
"git describe --match" learned to take multiple patterns in v2.13
series, but the feature ignored the patterns after the first one
and did not work at all.  This has been fixed.

* jk/describe-omit-some-refs:
  describe: fix matching to actually match all patterns
2017-10-18 14:19:01 +09:00
Junio C Hamano
14431c717d Merge branch 'aw/gc-lockfile-fscanf-fix' into maint
"git gc" tries to avoid running two instances at the same time by
reading and writing pid/host from and to a lock file; it used to
use an incorrect fscanf() format when reading, which has been
corrected.

* aw/gc-lockfile-fscanf-fix:
  gc: call fscanf() with %<len>s, not %<len>c, when reading hostname
2017-10-18 14:18:59 +09:00
Junio C Hamano
aec2eb8bfd Merge branch 'rk/commit-tree-make-F-verbatim' into maint
Unlike "git commit-tree < file", "git commit-tree -F file" did not
pass the contents of the file verbatim and instead completed an
incomplete line at the end, if exists.  The latter has been updated
to match the behaviour of the former.

* rk/commit-tree-make-F-verbatim:
  commit-tree: do not complete line in -F input
2017-10-18 14:18:58 +09:00
Junio C Hamano
6b895039f4 Merge branch 'mh/packed-ref-store-prep' into maint
Fix regression to "gitk --bisect" by a recent update.

* mh/packed-ref-store-prep:
  rev-parse: don't trim bisect refnames
2017-10-18 14:18:58 +09:00
Junio C Hamano
1c0b983a77 Merge branch 'jk/ref-filter-colors-fix'
This is the "theoretically more correct" approach of simply
stepping back to the state before plumbing commands started paying
attention to "color.ui" configuration variable.

Let's run with this one.

* jk/ref-filter-colors-fix:
  tag: respect color.ui config
  Revert "color: check color.ui in git_default_config()"
  Revert "t6006: drop "always" color config tests"
  Revert "color: make "always" the same as "auto" in config"
2017-10-18 10:19:08 +09:00
Junio C Hamano
7ccc94ff45 check-ref-format --branch: strip refs/heads/ using skip_prefix
The expansion returned from strbuf_check_branch_ref always starts with
"refs/heads/" by construction, but there is nothing about its name or
advertised API making that obvious.  This command is used to process
human-supplied input from the command line and is usually not the
inner loop, so we can spare some cycles to be more defensive.  Instead
of hard-coding the offset strlen("refs/heads/") to skip, verify that
the expansion actually starts with refs/heads/.

[jn: split out from a larger patch, added explanation]

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-18 06:12:01 +09:00
Jeff King
b521fd1228 tag: respect color.ui config
Since 11b087adfd (ref-filter: consult want_color() before
emitting colors, 2017-07-13), we expect that setting
"color.ui" to "always" will enable color tag formats even
without a tty.  As that commit was built on top of
136c8c8b8f (color: check color.ui in git_default_config(),
2017-07-13) from the same series, we didn't need to touch
tag's config parsing at all.

However, since we reverted 136c8c8b8f, we now need to
explicitly call git_color_default_config() to make this
work.

Let's do so, and also restore the test dropped in 0c88bf5050
(provide --color option for all ref-filter users,
2017-10-03). That commit swapped out our "color.ui=always"
test for "--color" in preparation for "always" going away.
But since it is here to stay, we should test both cases.

Note that for-each-ref also lost its color.ui support as
part of reverting 136c8c8b8f. But as a plumbing command, it
should _not_ respect the color.ui config. Since it also
gained a --color option in 0c88bf5050, that's the correct
way to ask it for color. We'll continue to test that, and
confirm that "color.ui" is not respected.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-17 15:10:13 +09:00
Jeff King
33c643bb08 Revert "color: check color.ui in git_default_config()"
This reverts commit 136c8c8b8f.

That commit was trying to address a bug caused by 4c7f1819b3
(make color.ui default to 'auto', 2013-06-10), in which
plumbing like diff-tree defaulted to "auto" color, but did
not respect a "color.ui" directive to disable it.

But it also meant that we started respecting "color.ui" set
to "always". This was a known problem, but 4c7f1819b3 argued
that nobody ought to be doing that. However, that turned out
to be wrong, and we got a number of bug reports related to
"add -p" regressing in v2.14.2.

Let's revert 136c8c8b8, fixing the regression to "add -p".
This leaves the problem from 4c7f1819b3 unfixed, but:

  1. It's a pretty obscure problem in the first place. I
     only noticed it while working on the color code, and we
     haven't got a single bug report or complaint about it.

  2. We can make a more moderate fix on top by respecting
     "never" but not "always" for plumbing commands. This
     is just the minimal fix to go back to the working state
     we had before v2.14.2.

Note that this isn't a pure revert. We now have a test in
t3701 which shows off the "add -p" regression. This can be
flipped to success.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-17 15:09:52 +09:00
Junio C Hamano
433d62fea9 Merge branch 'jk/ui-color-always-to-auto-maint' (early part) into jk/ref-filter-colors-fix-maint
* 'jk/ui-color-always-to-auto-maint' (early part):
  color: make "always" the same as "auto" in config
  provide --color option for all ref-filter users
  t3205: use --color instead of color.branch=always
  t3203: drop "always" color test
  t6006: drop "always" color config tests
  t7502: use diff.noprefix for --verbose test
  t7508: use test_terminal for color output
  t3701: use test-terminal to collect color output
  t4015: prefer --color to -c color.diff=always
  test-terminal: set TERM=vt100
2017-10-17 15:08:31 +09:00
Junio C Hamano
7245ee3d6c Merge branch 'ds/avoid-overflow-in-midpoint-computation'
Code clean-up.

* ds/avoid-overflow-in-midpoint-computation:
  cleanup: fix possible overflow errors in binary search
2017-10-11 14:52:24 +09:00
Derrick Stolee
19716b21a4 cleanup: fix possible overflow errors in binary search
A common mistake when writing binary search is to allow possible
integer overflow by using the simple average:

	mid = (min + max) / 2;

Instead, use the overflow-safe version:

	mid = min + (max - min) / 2;

This translation is safe since the operation occurs inside a loop
conditioned on "min < max". The included changes were found using
the following git grep:

	git grep '/ *2;' '*.c'

Making this cleanup will prevent future review friction when a new
binary search is contructed based on existing code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-10 08:57:24 +09:00
Junio C Hamano
932b573406 Merge branch 'ks/branch-tweak-error-message-for-extra-args'
Error message tweak.

* ks/branch-tweak-error-message-for-extra-args:
  branch: change the error messages to be more meaningful
2017-10-07 16:27:55 +09:00
Junio C Hamano
da15b78e52 Merge branch 'jk/ui-color-always-to-auto'
Fix regression of "git add -p" for users with "color.ui = always"
in their configuration, by merging the topic below and adjusting it
for the 'master' front.

* jk/ui-color-always-to-auto:
  t7301: use test_terminal to check color
  t4015: use --color with --color-moved
  color: make "always" the same as "auto" in config
  provide --color option for all ref-filter users
  t3205: use --color instead of color.branch=always
  t3203: drop "always" color test
  t6006: drop "always" color config tests
  t7502: use diff.noprefix for --verbose test
  t7508: use test_terminal for color output
  t3701: use test-terminal to collect color output
  t4015: prefer --color to -c color.diff=always
  test-terminal: set TERM=vt100
2017-10-07 16:27:55 +09:00
Junio C Hamano
5261fefa4a Merge branch 'ma/builtin-unleak'
Many variables that points at a region of memory that will live
throughout the life of the program have been marked with UNLEAK
marker to help the leak checkers concentrate on real leaks..

* ma/builtin-unleak:
  builtin/: add UNLEAKs
2017-10-07 16:27:55 +09:00
Junio C Hamano
cfa0fd0ffc Merge branch 'sb/branch-avoid-repeated-strbuf-release'
* sb/branch-avoid-repeated-strbuf-release:
  branch: reset instead of release a strbuf
2017-10-07 16:27:54 +09:00
Junio C Hamano
e46ebc2754 Merge branch 'rs/cleanup-strbuf-users'
Code clean-up.

* rs/cleanup-strbuf-users:
  graph: use strbuf_addchars() to add spaces
  use strbuf_addstr() for adding strings to strbufs
  path: use strbuf_add_real_path()
2017-10-05 13:48:19 +09:00
Junio C Hamano
efe9d6ce33 Merge branch 'rs/resolve-ref-optional-result'
Code clean-up.

* rs/resolve-ref-optional-result:
  refs: pass NULL to resolve_refdup() if hash is not needed
  refs: pass NULL to refs_resolve_refdup() if hash is not needed
2017-10-05 13:48:19 +09:00
Stefan Beller
a9155c50bd branch: reset instead of release a strbuf
Our documentation advises to not re-use a strbuf, after strbuf_release
has been called on it. Use the proper reset instead.

Currently 'strbuf_release' releases and re-initializes the strbuf, so it
is safe, but slow. 'strbuf_reset' only resets the internal length variable,
such that this could also be accounted for as a micro-optimization.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-04 15:21:31 +09:00
Kaartic Sivaraam
f777623514 branch: change the error messages to be more meaningful
The error messages shown when the branch command is misused
by supplying it wrong number of parameters wasn't meaningful.
That's because it used the the phrase "too many branches"
assuming all parameters to be "valid" branch names. It's not
always the case as exemplified below,

        $ git branch
          foo
        * master

        $ git branch -m foo foo old
        fatal: too many branches for a rename operation

Change the messages to be more general thus making no assumptions
about the "parameters".

Signed-off-by: Kaartic Sivaraam <kaarticsivaraam91196@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-04 13:08:17 +09:00
Junio C Hamano
aebd23506e Merge branch 'jk/ui-color-always-to-auto-maint' into jk/ui-color-always-to-auto
* jk/ui-color-always-to-auto-maint:
  color: make "always" the same as "auto" in config
  provide --color option for all ref-filter users
  t3205: use --color instead of color.branch=always
  t3203: drop "always" color test
  t6006: drop "always" color config tests
  t7502: use diff.noprefix for --verbose test
  t7508: use test_terminal for color output
  t3701: use test-terminal to collect color output
  t4015: prefer --color to -c color.diff=always
  test-terminal: set TERM=vt100
2017-10-04 12:04:47 +09:00
Jeff King
0c88bf5050 provide --color option for all ref-filter users
When ref-filter learned about want_color() in 11b087adfd
(ref-filter: consult want_color() before emitting colors,
2017-07-13), it became useful to be able to turn colors off
and on for specific commands. For git-branch, you can do so
with --color/--no-color.

But for git-for-each-ref and git-tag, the other users of
ref-filter, you have no option except to tweak the
"color.ui" config setting. Let's give both of these commands
the usual color command-line options.

This is a bit more obvious as a method for overriding the
config. And it also prepares us for the behavior of "always"
changing (so that we are still left with a way of forcing
color when our output goes to a non-terminal).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-04 11:35:29 +09:00
Junio C Hamano
cb1083ca23 Merge branch 'jk/read-in-full'
Code clean-up to prevent future mistakes by copying and pasting
code that checks the result of read_in_full() function.

* jk/read-in-full:
  worktree: check the result of read_in_full()
  worktree: use xsize_t to access file size
  distinguish error versus short read from read_in_full()
  avoid looking at errno for short read_in_full() returns
  prefer "!=" when checking read_in_full() result
  notes-merge: drop dead zero-write code
  files-backend: prefer "0" for write_in_full() error check
2017-10-03 15:42:49 +09:00
Junio C Hamano
d4e93836a6 Merge branch 'jk/no-optional-locks'
Some commands (most notably "git status") makes an opportunistic
update when performing a read-only operation to help optimize later
operations in the same repository.  The new "--no-optional-locks"
option can be passed to Git to disable them.

* jk/no-optional-locks:
  git: add --no-optional-locks option
2017-10-03 15:42:49 +09:00
Junio C Hamano
3b48045c6c Merge branch 'sd/branch-copy'
"git branch" learned "-c/-C" to create a new branch by copying an
existing one.

* sd/branch-copy:
  branch: fix "copy" to never touch HEAD
  branch: add a --copy (-c) option to go with --move (-m)
  branch: add test for -m renaming multiple config sections
  config: create a function to format section headers
2017-10-03 15:42:48 +09:00
Junio C Hamano
b2a2c4d809 Merge branch 'bc/rev-parse-parseopt-fix'
Recent versions of "git rev-parse --parseopt" did not parse the
option specification that does not have the optional flags (*=?!)
correctly, which has been corrected.

* bc/rev-parse-parseopt-fix:
  parse-options: only insert newline in help text if needed
  parse-options: write blank line to correct output stream
  t0040,t1502: Demonstrate parse_options bugs
  git-rebase: don't ignore unexpected command line arguments
  rev-parse parseopt: interpret any whitespace as start of help text
  rev-parse parseopt: do not search help text for flag chars
  t1502: demonstrate rev-parse --parseopt option mis-parsing
2017-10-03 15:42:47 +09:00
Junio C Hamano
5f3108b7b6 Merge branch 'js/rebase-i-final'
The final batch to "git rebase -i" updates to move more code from
the shell script to C.

* js/rebase-i-final:
  rebase -i: rearrange fixup/squash lines using the rebase--helper
  t3415: test fixup with wrapped oneline
  rebase -i: skip unnecessary picks using the rebase--helper
  rebase -i: check for missing commits in the rebase--helper
  t3404: relax rebase.missingCommitsCheck tests
  rebase -i: also expand/collapse the SHA-1s via the rebase--helper
  rebase -i: do not invent onelines when expanding/collapsing SHA-1s
  rebase -i: remove useless indentation
  rebase -i: generate the script via rebase--helper
  t3415: verify that an empty instructionFormat is handled as before
2017-10-03 15:42:47 +09:00
René Scharfe
72d4a9a721 use strbuf_addstr() for adding strings to strbufs
Use strbuf_addstr() instead of strbuf_addf() for adding strings.  That's
simpler and makes the intent clearer.

Patch generated by Coccinelle and contrib/coccinelle/strbuf.cocci;
adjusted indentation in refs/packed-backend.c manually.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-02 13:13:46 +09:00
Martin Ågren
886e1084d7 builtin/: add UNLEAKs
Add some UNLEAKs where we are about to return from `cmd_*`. UNLEAK the
variables in the same order as we've declared them. While addressing
`msg` in builtin/tag.c, convert the existing `strbuf_release()` calls as
well.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-02 13:03:10 +09:00
René Scharfe
efbd4fdfc9 refs: pass NULL to resolve_refdup() if hash is not needed
This allows us to get rid of several write-only variables.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-10-01 17:27:14 +09:00
Junio C Hamano
69c54c7284 Merge branch 'ma/leakplugs'
Memory leaks in various codepaths have been plugged.

* ma/leakplugs:
  pack-bitmap[-write]: use `object_array_clear()`, don't leak
  object_array: add and use `object_array_pop()`
  object_array: use `object_array_clear()`, not `free()`
  leak_pending: use `object_array_clear()`, not `free()`
  commit: fix memory leak in `reduce_heads()`
  builtin/commit: fix memory leak in `prepare_index()`
2017-09-29 11:23:43 +09:00
Junio C Hamano
14a8168e2f Merge branch 'rj/no-sign-compare'
Many codepaths have been updated to squelch -Wsign-compare
warnings.

* rj/no-sign-compare:
  ALLOC_GROW: avoid -Wsign-compare warnings
  cache.h: hex2chr() - avoid -Wsign-compare warnings
  commit-slab.h: avoid -Wsign-compare warnings
  git-compat-util.h: xsize_t() - avoid -Wsign-compare warnings
2017-09-29 11:23:42 +09:00
Junio C Hamano
8096e1d385 Merge branch 'jt/fast-export-copy-modify-fix'
"git fast-export" with -M/-C option issued "copy" instruction on a
path that is simultaneously modified, which was incorrect.

* jt/fast-export-copy-modify-fix:
  fast-export: do not copy from modified file
2017-09-29 11:23:42 +09:00
Junio C Hamano
8c1bc7c244 Merge branch 'mk/describe-match-with-all'
"git describe --match <pattern>" has been taught to play well with
the "--all" option.

* mk/describe-match-with-all:
  describe: teach --match to handle branches and remotes
2017-09-29 11:23:41 +09:00
Junio C Hamano
73ecdc606e Merge branch 'rs/resolve-ref-optional-result'
Code clean-up.

* rs/resolve-ref-optional-result:
  refs: pass NULL to resolve_ref_unsafe() if hash is not needed
  refs: pass NULL to refs_resolve_ref_unsafe() if hash is not needed
  refs: make sha1 output parameter of refs_resolve_ref_unsafe() optional
2017-09-28 14:47:56 +09:00
Junio C Hamano
59373a4e03 Merge branch 'jk/fallthrough'
Many codepaths have been updated to squelch -Wimplicit-fallthrough
warnings from Gcc 7 (which is a good code hygiene).

* jk/fallthrough:
  consistently use "fallthrough" comments in switches
  curl_trace(): eliminate switch fallthrough
  test-line-buffer: simplify command parsing
2017-09-28 14:47:53 +09:00
Junio C Hamano
bfbc2fccfd Merge branch 'jk/diff-blob'
"git cat-file --textconv" started segfaulting recently, which
has been corrected.

* jk/diff-blob:
  cat-file: handle NULL object_context.path
2017-09-28 14:47:53 +09:00
Junio C Hamano
a515136c52 Merge branch 'jk/describe-omit-some-refs'
"git describe --match" learned to take multiple patterns in v2.13
series, but the feature ignored the patterns after the first one
and did not work at all.  This has been fixed.

* jk/describe-omit-some-refs:
  describe: fix matching to actually match all patterns
2017-09-28 14:47:52 +09:00
Jeff King
27344d6a6c git: add --no-optional-locks option
Some tools like IDEs or fancy editors may periodically run
commands like "git status" in the background to keep track
of the state of the repository. Some of these commands may
refresh the index and write out the result in an
opportunistic way: if they can get the index lock, then they
update the on-disk index with any updates they find. And if
not, then their in-core refresh is lost and just has to be
recomputed by the next caller.

But taking the index lock may conflict with other operations
in the repository. Especially ones that the user is doing
themselves, which _aren't_ opportunistic. In other words,
"git status" knows how to back off when somebody else is
holding the lock, but other commands don't know that status
would be happy to drop the lock if somebody else wanted it.

There are a couple possible solutions:

  1. Have some kind of "pseudo-lock" that allows other
     commands to tell status that they want the lock.

     This is likely to be complicated and error-prone to
     implement (and maybe even impossible with just
     dotlocks to work from, as it requires some
     inter-process communication).

  2. Avoid background runs of commands like "git status"
     that want to do opportunistic updates, preferring
     instead plumbing like diff-files, etc.

     This is awkward for a couple of reasons. One is that
     "status --porcelain" reports a lot more about the
     repository state than is available from individual
     plumbing commands. And two is that we actually _do_
     want to see the refreshed index. We just don't want to
     take a lock or write out the result. Whereas commands
     like diff-files expect us to refresh the index
     separately and write it to disk so that they can depend
     on the result. But that write is exactly what we're
     trying to avoid.

  3. Ask "status" not to lock or write the index.

     This is easy to implement. The big downside is that any
     work done in refreshing the index for such a call is
     lost when the process exits. So a background process
     may end up re-hashing a changed file multiple times
     until the user runs a command that does an index
     refresh themselves.

This patch implements the option 3. The idea (and the test)
is largely stolen from a Git for Windows patch by Johannes
Schindelin, 67e5ce7f63 (status: offer *not* to lock the
index and update it, 2016-08-12). The twist here is that
instead of making this an option to "git status", it becomes
a "git" option and matching environment variable.

The reason there is two-fold:

  1. An environment variable is carried through to
     sub-processes. And whether an invocation is a
     background process or not should apply to the whole
     process tree. So you could do "git --no-optional-locks
     foo", and if "foo" is a script or alias that calls
     "status", you'll still get the effect.

  2. There may be other programs that want the same
     treatment.

     I've punted here on finding more callers to convert,
     since "status" is the obvious one to call as a repeated
     background job. But "git diff"'s opportunistic refresh
     of the index may be a good candidate.

The test is taken from 67e5ce7f63, and it's worth repeating
Johannes's explanation:

  Note that the regression test added in this commit does
  not *really* verify that no index.lock file was written;
  that test is not possible in a portable way. Instead, we
  verify that .git/index is rewritten *only* when `git
  status` is run without `--no-optional-locks`.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-27 16:11:01 +09:00
Jeff King
8a1a8d2ad1 worktree: check the result of read_in_full()
We try to read "len" bytes into a buffer and just assume
that it happened correctly. In practice this should usually
be the case, since we just stat'd the file to get the
length.  But we could be fooled by transient errors or by
other processes racily truncating the file.

Let's be more careful. There's a slim chance this could
catch a real error, but it also prevents people and tools
from getting worried while reading the code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-27 15:46:05 +09:00
Jeff King
228740b67b worktree: use xsize_t to access file size
To read the "gitdir" file into memory, we stat the file and
allocate a buffer. But we store the size in an "int", which
may be truncated. We should use a size_t and xsize_t(),
which will detect truncation.

An overflow is unlikely for a "gitdir" file, but it's a good
practice to model.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-27 15:45:57 +09:00