Disable the recent mergetool's hideresolved feature by default for
backward compatibility and safety.
* jn/mergetool-hideresolved-is-optional:
doc: describe mergetool configuration in git-mergetool(1)
mergetool: do not enable hideResolved by default
template_dir starts off pointing to either argv or nothing. However if
the value supplied in argv is a relative path, absolute_pathdup() is
used to turn it into an absolute path. absolute_pathdup() allocates
a new string, and we then "leak" it when cmd_init_db() completes.
We don't bother to actually free the return value (instead we UNLEAK
it), because there's no significant advantage to doing so here.
Correctly freeing it would require more significant changes to code flow
which would be more noisy than beneficial.
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The primary goal of this change is to stop leaking init_db_template_dir.
This leak can happen because:
1. git_init_db_config() allocates new memory into init_db_template_dir
without first freeing the existing value.
2. init_db_template_dir might already contain data, either because:
2.1 git_config() can be invoked twice with this callback in a single
process - at least 2 allocations are likely.
2.2 A single git_config() allocation can invoke the callback multiple
times for a given key (see further explanation in the function
docs) - each of those calls will trigger another leak.
The simplest fix for the leak would be to free(init_db_template_dir)
before overwriting it. Instead we choose to convert to fetching
init.templatedir via git_config_get_value() as that is more explicit,
more efficient, and avoids allocations (the returned result is owned by
the config cache, so we aren't responsible for freeing it).
If we remove init_db_template_dir, git_init_db_config() ends up being
responsible only for forwarding core.* config values to
platform_core_config(). However platform_core_config() already ignores
non-core.* config values, so we can safely remove git_init_db_config()
and invoke git_config() directly with platform_core_config() as the
callback.
The platform_core_config forwarding was originally added in:
287853392a (mingw: respect core.hidedotfiles = false in git-init again, 2019-03-11
And I suspect the potential for a leak existed since the original
implementation of git_init_db_config in:
90b45187ba (Add `init.templatedir` configuration variable., 2010-02-17)
LSAN output from t0001:
Direct leak of 73 byte(s) in 1 object(s) allocated from:
#0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x9a7276 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
#2 0x9362ad in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
#3 0x936eaa in strbuf_add /home/ahunt/oss-fuzz/git/strbuf.c:295:2
#4 0x868112 in strbuf_addstr /home/ahunt/oss-fuzz/git/./strbuf.h:304:2
#5 0x86a8ad in expand_user_path /home/ahunt/oss-fuzz/git/path.c:758:2
#6 0x720bb1 in git_config_pathname /home/ahunt/oss-fuzz/git/config.c:1287:10
#7 0x5960e2 in git_init_db_config /home/ahunt/oss-fuzz/git/builtin/init-db.c:161:11
#8 0x7255b8 in configset_iter /home/ahunt/oss-fuzz/git/config.c:1982:7
#9 0x7253fc in repo_config /home/ahunt/oss-fuzz/git/config.c:2311:2
#10 0x725ca7 in git_config /home/ahunt/oss-fuzz/git/config.c:2399:2
#11 0x593e8d in create_default_files /home/ahunt/oss-fuzz/git/builtin/init-db.c:225:2
#12 0x5935c6 in init_db /home/ahunt/oss-fuzz/git/builtin/init-db.c:449:11
#13 0x59588e in cmd_init_db /home/ahunt/oss-fuzz/git/builtin/init-db.c:714:9
#14 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#15 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#16 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#17 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#18 0x69c4de in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#19 0x7f23552d6349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make sure that we release the temporary strbuf during dwim_branch() for
all codepaths (and not just for the early return).
This leak appears to have been introduced in:
f60a7b763f (worktree: teach "add" to check out existing branches, 2018-04-24)
Note that UNLEAK(branchname) is still needed: the returned result is
used in add(), and is stored in a pointer which is used to point at one
of:
- a string literal ("HEAD")
- member of argv (whatever the user specified in their invocation)
- or our newly allocated string returned from dwim_branch()
Fixing the branchname leak isn't impossible, but does not seem
worthwhile given that add() is called directly from cmd_main(), and
cmd_main() returns immediately thereafter - UNLEAK is good enough.
This leak was found when running t0001 with LSAN, see also LSAN output
below:
Direct leak of 60 byte(s) in 1 object(s) allocated from:
#0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x9ab076 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
#2 0x939fcd in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
#3 0x93af53 in strbuf_splice /home/ahunt/oss-fuzz/git/strbuf.c:239:3
#4 0x83559a in strbuf_check_branch_ref /home/ahunt/oss-fuzz/git/object-name.c:1593:2
#5 0x6988b9 in dwim_branch /home/ahunt/oss-fuzz/git/builtin/worktree.c:454:20
#6 0x695f8f in add /home/ahunt/oss-fuzz/git/builtin/worktree.c:525:19
#7 0x694a04 in cmd_worktree /home/ahunt/oss-fuzz/git/builtin/worktree.c:1036:10
#8 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#9 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#10 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#11 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#12 0x69caee in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#13 0x7f7b7dd10349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most of these pointers can safely be freed when cmd_clone() completes,
therefore we make sure to free them. The one exception is that we
have to UNLEAK(repo) because it can point either to argv[0], or a
malloc'd string returned by absolute_pathdup().
We also have to free(path) in the middle of cmd_clone(): later during
cmd_clone(), path is unconditionally overwritten with a different path,
triggering a leak. Freeing the first path immediately after use (but
only in the case where it contains data) seems like the cleanest
solution, as opposed to freeing it unconditionally before path is reused
for another path. This leak appears to have been introduced in:
f38aa83f9a (use local cloning if insteadOf makes a local URL, 2014-07-17)
These leaks were found when running t0001 with LSAN, see also an excerpt
of the LSAN output below (the full list is omitted because it's far too
long, and mostly consists of indirect leakage of members of the refs we
are freeing).
Direct leak of 178 byte(s) in 1 object(s) allocated from:
#0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
#1 0x9a6ff4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
#2 0x9a6fca in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
#3 0x8ce296 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
#4 0x8d2ebd in guess_remote_head /home/ahunt/oss-fuzz/git/remote.c:2215:10
#5 0x51d0c5 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1308:4
#6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#10 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#11 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Direct leak of 165 byte(s) in 1 object(s) allocated from:
#0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
#1 0x9a6fc4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
#2 0x9a6f9a in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
#3 0x8ce266 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
#4 0x51e9bd in wanted_peer_refs /home/ahunt/oss-fuzz/git/builtin/clone.c:574:21
#5 0x51cfe1 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1284:17
#6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#10 0x69c42e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#11 0x7f8fef0c2349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Direct leak of 178 byte(s) in 1 object(s) allocated from:
#0 0x49a53d in malloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
#1 0x9a6ff4 in do_xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:41:8
#2 0x9a6fca in xmalloc /home/ahunt/oss-fuzz/git/wrapper.c:62:9
#3 0x8ce296 in copy_ref /home/ahunt/oss-fuzz/git/remote.c:885:8
#4 0x8d2ebd in guess_remote_head /home/ahunt/oss-fuzz/git/remote.c:2215:10
#5 0x51d0c5 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1308:4
#6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#10 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#11 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Direct leak of 165 byte(s) in 1 object(s) allocated from:
#0 0x49a6b2 in calloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:154:3
#1 0x9a72f2 in xcalloc /home/ahunt/oss-fuzz/git/wrapper.c:140:8
#2 0x8ce203 in alloc_ref_with_prefix /home/ahunt/oss-fuzz/git/remote.c:867:20
#3 0x8ce1a2 in alloc_ref /home/ahunt/oss-fuzz/git/remote.c:875:9
#4 0x72f63e in process_ref_v2 /home/ahunt/oss-fuzz/git/connect.c:426:8
#5 0x72f21a in get_remote_refs /home/ahunt/oss-fuzz/git/connect.c:525:8
#6 0x979ab7 in handshake /home/ahunt/oss-fuzz/git/transport.c:305:4
#7 0x97872d in get_refs_via_connect /home/ahunt/oss-fuzz/git/transport.c:339:9
#8 0x9774b5 in transport_get_remote_refs /home/ahunt/oss-fuzz/git/transport.c:1388:4
#9 0x51cf80 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1271:9
#10 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#11 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#12 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#13 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#14 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#15 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Direct leak of 105 byte(s) in 1 object(s) allocated from:
#0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x9a71f6 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
#2 0x93622d in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
#3 0x937a73 in strbuf_addch /home/ahunt/oss-fuzz/git/./strbuf.h:231:3
#4 0x939fcd in strbuf_add_absolute_path /home/ahunt/oss-fuzz/git/strbuf.c:911:4
#5 0x69d3ce in absolute_pathdup /home/ahunt/oss-fuzz/git/abspath.c:261:2
#6 0x51c688 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:1021:10
#7 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#8 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#9 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#10 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#11 0x69c45e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#12 0x7f6a459d5349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
dwim_ref() allocs a new string into ref. Instead of setting to NULL to
discard it, we can FREE_AND_NULL.
This leak appears to have been introduced in:
4cf76f6bbf (builtin/reset: compute checkout metadata for reset, 2020-03-16)
This leak was found when running t0001 with LSAN, see also LSAN output below:
Direct leak of 5 byte(s) in 1 object(s) allocated from:
#0 0x486514 in strdup /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_interceptors.cpp:452:3
#1 0x9a7108 in xstrdup /home/ahunt/oss-fuzz/git/wrapper.c:29:14
#2 0x8add6b in expand_ref /home/ahunt/oss-fuzz/git/refs.c:670:12
#3 0x8ad777 in repo_dwim_ref /home/ahunt/oss-fuzz/git/refs.c:644:22
#4 0x6394af in dwim_ref /home/ahunt/oss-fuzz/git/./refs.h:162:9
#5 0x637e5c in cmd_reset /home/ahunt/oss-fuzz/git/builtin/reset.c:426:4
#6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#10 0x69c5ce in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#11 0x7f57ebb9d349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
shorten_unambiguous_ref() returns an allocated string. We have to
track it separately from the const refname.
This leak has existed since:
9ab55daa55 (git symbolic-ref --delete $symref, 2012-10-21)
This leak was found when running t0001 with LSAN, see also LSAN output
below:
Direct leak of 19 byte(s) in 1 object(s) allocated from:
#0 0x486514 in strdup /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_interceptors.cpp:452:3
#1 0x9ab048 in xstrdup /home/ahunt/oss-fuzz/git/wrapper.c:29:14
#2 0x8b452f in refs_shorten_unambiguous_ref /home/ahunt/oss-fuzz/git/refs.c
#3 0x8b47e8 in shorten_unambiguous_ref /home/ahunt/oss-fuzz/git/refs.c:1287:9
#4 0x679fce in check_symref /home/ahunt/oss-fuzz/git/builtin/symbolic-ref.c:28:14
#5 0x679ad8 in cmd_symbolic_ref /home/ahunt/oss-fuzz/git/builtin/symbolic-ref.c:70:9
#6 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#7 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#8 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#9 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#10 0x69cc6e in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#11 0x7f98388a4349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fc47391e24 (drop vcs-svn experiment, 2020-08-13) removed most vcs-svn
files. Drop the remaining header files as well, as they are no longer
used.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add and apply a semantic patch for converting code that open-codes
CALLOC_ARRAY to use it instead. It shortens the code and infers the
element size automatically.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Make CALLOC_ARRAY usable like a function by requiring callers to supply
the trailing semicolon, which all of the current ones already do. With
the extra semicolon e.g. the following code wouldn't compile because it
disconnects the "else" from the "if":
if (condition)
CALLOC_ARRAY(ptr, n);
else
whatever();
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the EXAMPLES section, git-push(1) says that 'git push origin' pushes
the current branch to the value of the 'remote.origin.merge'
configuration.
This wording (which dates back to b2ed944af7 (push: switch default from
"matching" to "simple", 2013-01-04)) is incorrect. There is no such
configuration as 'remote.<name>.merge'. This likely was originally
intended to read "branch.<name>.merge" instead.
Indeed, when 'push.default' is 'simple' (which is the default value, and
is applicable in this scenario per "without additional configuration"),
setup_push_upstream() dies if the branch's local name does not match
'branch.<name>.merge'.
Correct this long-standing typo to resolve some recent confusion on the
intended behavior of this example.
Reported-by: Adam Sharafeddine <adam.shrfdn@gmail.com>
Reported-by: Fabien Terrani <terranifabien@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In particular, this describes mergetool.hideResolved, which can help
users discover this setting (either because it may be useful to them
or in order to understand mergetool's behavior if they have forgotten
setting it in the past).
Tested by running
make -C Documentation git-mergetool.1
man Documentation/git-mergetool.1
and reading through the page.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 98ea309b3f (mergetool: add hideResolved configuration,
2021-02-09) introduced the mergetool.hideResolved setting to reduce
the clutter in viewing non-conflicted sections of files in a
mergetool, it enabled it by default, explaining:
No adverse effects were noted in a small survey of popular mergetools[1]
so this behavior defaults to `true`.
In practice, alas, adverse effects do appear. A few issues:
1. No indication is shown in the UI that the base, local, and remote
versions shown have been modified by additional resolution. This
is inherent in the design: the idea of mergetool.hideResolved is to
convince a mergetool that expects pristine local, base, and remote
files to show partially resolved verisons of those files instead;
there is no additional source of information accessible to the
mergetool to see where the resolution has happened.
(By contrast, a mergetool generating the partial resolution from
conflict markers for itself would be able to hilight the resolved
sections with a different color.)
A user accustomed to seeing the files without partial resolution
gets no indication that this behavior has changed when they upgrade
Git.
2. If the computed merge did not line up the files correctly (for
example due to repeated sections in the file), the partially
resolved files can be misleading and do not have enough information
to reconstruct what happened and compute the correct merge result.
3. Resolving a conflict can involve information beyond the textual
conflict. For example, if the local and remote versions added
overlapping functionality in different ways, seeing the full
unresolved versions of each alongside the base gives information
about each side's intent that makes it possible to come up with a
resolution that combines those two intents. By contrast, when
starting with partially resolved versions of those files, one can
produce a subtly wrong resolution that includes redundant extra
code added by one side that is not needed in the approach taken
on the other.
All that said, a user wanting to focus on textual conflicts with
reduced clutter can still benefit from mergetool.hideResolved=true as
a way to deemphasize sections of the code that resolve cleanly without
requiring any changes to the invoked mergetool. The caveats described
above are reduced when the user has explicitly turned this on, because
then the user is aware of them.
Flip the default to 'false'.
Reported-by: Dana Dahlstrom <dahlstrom@google.com>
Helped-by: Seth House <seth@eseth.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
credential_approve() already checks for a non-empty password before
saving, so there's no need to do the extra check here.
Signed-off-by: John Szakmeister <john@szakmeister.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We already looked for the PKI credentials in the credential store, but
failed to approve it on success. Meaning, the PKI certificate password
was never stored and git would request it on every connection to the
remote. Let's complete the chain by storing the certificate password on
success.
Likewise, we also need to reject the credential when there is a failure.
Curl appears to report client-related certificate issues are reported
with the CURLE_SSL_CERTPROBLEM error. This includes not only a bad
password, but potentially other client certificate related problems.
Since we cannot get more information from curl, we'll go ahead and
reject the credential upon receiving that error, just to be safe and
avoid caching or saving a bad password.
Signed-off-by: John Szakmeister <john@szakmeister.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Every %(describe) placeholder in $Format:...$ strings in files with the
attribute export-subst is expanded by calling git describe. This can
potentially result in a lot of such calls per archive. That's OK for
local repositories under control of the user of git archive, but could
be a problem for hosted repositories.
Expand only a single %(describe) placeholder per archive for now to
avoid denial-of-service attacks. We can make this limit configurable
later if needed, but let's start out simple.
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The basename comparison optimization implemented in
find_basename_matches() is very beneficial since it allows a source to
sometimes only be compared with one other file instead of N other files.
When a match is found, both a source and destination can be removed from
the matrix of inexact rename comparisons. In contrast, the irrelevant
source optimization only allows us to remove a source from the matrix of
inexact rename comparisons...but it has the advantage of allowing a
source file to not even be loaded into memory at all and be compared to
0 other files. Generally, not even comparing is a bigger performance
win, so when both optimizations could apply, prefer to use the
irrelevant-source optimization.
For the testcases mentioned in commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2020-10-28),
this change improves the performance as follows:
Before After
no-renames: 5.708 s ± 0.111 s 5.680 s ± 0.096 s
mega-renames: 102.171 s ± 0.440 s 13.812 s ± 0.162 s
just-one-mega: 3.471 s ± 0.015 s 506.0 ms ± 3.9 ms
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diffcore_rename_extended() will do a bunch of setup, then check for
exact renames, then abort before inexact rename detection if there are
no more sources or destinations that need to be matched. It will
sometimes be the case, however, that either
* we start with neither any sources or destinations
* we start with no *relevant* sources
In the first of these two cases, the setup and exact rename detection
will be very cheap since there are 0 files to operate on. In the second
case, it is quite possible to have thousands of files with none of the
source ones being relevant. Avoid calling diffcore_rename_extended() or
even some of the setup before diffcore_rename_extended() when we can
determine that rename detection is unnecessary.
For the testcases mentioned in commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2020-10-28),
this change improves the performance as follows:
Before After
no-renames: 6.003 s ± 0.048 s 5.708 s ± 0.111 s
mega-renames: 114.009 s ± 0.236 s 102.171 s ± 0.440 s
just-one-mega: 3.489 s ± 0.017 s 3.471 s ± 0.015 s
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The past several commits determined conditions when rename sources might
be needed, and filled a relevant_sources strset with those paths. Pass
these along to diffcore_rename_extended() to use to limit the sources
that we need to detect renames for.
For the testcases mentioned in commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2020-10-28),
this change improves the performance as follows:
Before After
no-renames: 12.596 s ± 0.061 s 6.003 s ± 0.048 s
mega-renames: 130.465 s ± 0.259 s 114.009 s ± 0.236 s
just-one-mega: 3.958 s ± 0.010 s 3.489 s ± 0.017 s
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of directory rename detection is that if one side of history
renames a directory, and the other side adds new files under the old
directory, then the merge can move those new files into the new
directory. This leads to the following important observation:
* If the other side does not add any new files under the old
directory, we do not need to detect any renames for that directory.
Similarly, directory rename detection had an important requirement:
* If a directory still exists on one side of history, it has not been
renamed on that side of history. (See section 4 of t6423 or
Documentation/technical/directory-rename-detection.txt for more
details).
Using these two bits of information, we note that directory rename
detection is only needed in cases where (1) directories exist in the
merge base and on one side of history (i.e. dirmask == 3 or dirmask ==
5), and (2) where there is some new file added to that directory on the
side where it still exists (thus where the file has filemask == 2 or
filemask == 4, respectively). This has to be done in two steps, because
we have the dirmask when we are first considering the directory, and
won't get the filemasks for the files within it until we recurse into
that directory. So, we save
dir_rename_mask = dirmask - 1
when we hit a directory that is missing on one side, and then later look
for cases of
filemask == dir_rename_mask
One final note is that as soon as we hit a directory that needs
directory rename detection, we will need to detect renames in all
subdirectories of that directory as well due to the "majority rules"
decision when files are renamed into different directory hierarchies.
We arbitrarily use the special value of 0x07 to record when we've hit
such a directory.
The combination of all the above mean that we introduce a variable
named dir_rename_mask (couldn't think of a better name) which has one
of the following values as we traverse into a directory:
* 0x00: directory rename detection not needed
* 0x02 or 0x04: directory rename detection only needed if files added
* 0x07: directory rename detection definitely needed
We then pass this value through to add_pairs() so that it can mark
location_relevant as true only when dir_rename_mask is 0x07.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add traverse_trees_wrapper() and traverse_trees_wrapper_callback()
functions. The former runs traverse_trees() with info->fn set to
traverse_trees_wrapper_callback, in order to simply save all the entries
without processing or recursing into any of them. This step allows
extra computation to be done (e.g. checking some condition across all
files) that can be used later. Then, after that is completed, it
iterates over all the saved entries and calls the original info->fn
callback with the saved data.
Currently, this does nothing more than marginally slowing down the tree
traversal since we do not take advantage of the opportunity to compute
anything special in traverse_trees_wrapper_callback(), and thus the real
callback will be called identically as it would have been without this
extra wrapper. However, a subsequent commit will add some special
computation of some values that the real callback will be able to use.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to determine whether directory rename detection is needed, we
as a pre-requisite need a way to traverse through all the files in a
given tree before visiting any directories within that tree.
traverse_trees() only iterates through the entries in the order they
appear, so add some data structures that will store all the entries as
we iterate through them in traverse_trees(), which will allow us to
re-traverse them in our desired order.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
rename detection works by trying to pair all file deletions (or
"sources") with all file additions (or "destinations"), checking
similarity, and then marking the sufficiently similar ones as renames.
This can be expensive if there are many sources and destinations on a
given side of history as it results in an N x M comparison matrix.
However, there are many cases where we can compute in advance that
detecting renames for some of the sources provides no useful information
and thus that we can exclude those sources from the matrix.
To see why, first note that the merge machinery uses detected renames in
two ways:
* directory rename detection: when one side of history renames a
directory, and the other side of history adds new files to that
directory, we want to be able to warn the user about the need to
chose whether those new files stay in the old directory or move
to the new one.
* three-way content merging: in order to do three-way content merging
of files, we need three different file versions. If one side of
history renamed a file, then some of the content for the file is
found under a different path than in the merge base or on the
other side of history.
Add a simple testcase showing the two kinds of reasons renames are
relevant; it's a testcase that will only pass if we detect both kinds of
needed renames.
Other than the testcase added above, this commit concentrates just on
the three-way content merging; it will punt and mark all sources as
needed for directory rename detection, and leave it to future commits to
narrow that down more.
The point of three-way content merging is to reconcile changes made on
*both* sides of history. What if the file wasn't modified on both
sides? There are two possibilities:
* If it wasn't modified on the renamed side:
-> then we get to do exact rename detection, which is cheap.
* If it wasn't modified on the unrenamed side:
-> then detection of a rename for that source file is irrelevant
That latter claim might be surprising at first, so let's walk through a
case to show why rename detection for that source file is irrelevant.
Let's use two filenames, old.c & new.c, with the following abbreviated
object ids (and where the value '000000' is used to denote that the file
is missing in that commit):
old.c new.c
MERGE_BASE: 01d01d 000000
MERGE_SIDE1: 01d01d 000000
MERGE_SIDE2: 000000 5e1ec7
If the rename *isn't* detected:
then old.c looks like it was unmodified on one side and deleted on
the other and should thus be removed. new.c looks like a new file we
should keep as-is.
If the rename *is* detected:
then a three-way content merge is done. Since the version of the
file in MERGE_BASE and MERGE_SIDE1 are identical, the three-way merge
will produce exactly the version of the file whose abbreviated
object id is 5e1ec7. It will record that file at the path new.c,
while removing old.c from the directory.
Note that these two results are identical -- a single file named 'new.c'
with object id 5e1ec7. In other words, it doesn't matter if the rename
is detected in the case where the file is unmodified on the unrenamed
side.
Use this information to compute whether we need rename detection for
each source created in add_pair().
It's probably worth noting that there used to be a few other edge or
corner cases besides three-way content merges and directory rename
detection where lack of rename detection could have affected the result,
but those cases actually highlighted where conflict resolution methods
were not consistent with each other. Fixing those inconsistencies were
thus critically important to enabling this optimization. That work
involved the following:
* bringing consistency to add/add, rename/add, and rename/rename
conflict types, as done back in the topic merged at commit
ac193e0e0a ("Merge branch 'en/merge-path-collision'", 2019-01-04),
and further extended in commits 2a7c16c980 ("t6422, t6426: be more
flexible for add/add conflicts involving renames", 2020-08-10) and
e8eb99d4a6 ("t642[23]: be more flexible for add/add conflicts
involving pair renames", 2020-08-10)
* making rename/delete more consistent with modify/delete
as done in commits 1f3c9ba707 ("t6425: be more flexible with
rename/delete conflict messages", 2020-08-10) and 727c75b23f
("t6404, t6423: expect improved rename/delete handling in ort
backend", 2020-10-26)
Since the set of relevant_sources we compute has not yet been narrowed
down for directory rename detection, we do not pass it to
diffcore_rename_extended() yet. That will be done after subsequent
commits narrow down the list of relevant_sources needed for directory
rename detection reasons.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add the ability to diffcore_rename_extended() to allow external callers
to declare that they only need renames detected for a subset of source
files, and use that information to skip detecting renames for them.
There are two important pieces to this optimization that may not be
obvious at first glance:
* We do not require callers to just filter the filepairs out
to remove the non-relevant sources, because exact rename detection
is fast and when it finds a match it can remove both a source and a
destination whereas the relevant_sources filter can only remove a
source.
* We need to filter out the source pairs in a preliminary pass instead
of adding a
strset_contains(relevant_sources, one->path)
check within the nested matrix loop. The reason for that is if we
have 30k renames, doing 30k * 30k = 900M strset_contains() calls
becomes extraordinarily expensive and defeats the performance gains
from this change; we only want to do 30k such calls instead.
If callers pass NULL for relevant_sources, that is special cases to
treat all sources as relevant. Since all callers currently pass NULL,
this optimization does not yet have any effect. Subsequent commits will
have merge-ort compute a set of relevant_sources to restrict which
sources we detect renames for, and have merge-ort pass that set of
relevant_sources to diffcore_rename_extended().
A note about filtering order:
Some may be curious why we don't filter out irrelevant sources at the
same time we filter out exact renames. While that technically could be
done at this point, there are two reasons to defer it:
First, was to reinforce a lesson that was too easy to forget. As I
mentioned above, in the past I filtered irrelevant sources out before
exact rename checking, and then discovered that exact renames' ability
to remove both sources and destinations was an important consideration
and thus doing the filtering after exact rename checking would speed
things up. Then at some point I realized that basename matching could
also remove both sources and destinations, and decided to put irrelevant
source filtering after basename filtering. That slowed things down a
lot. But, despite learning about this important ordering, in later
restructuring I forgot and made the same mistake of putting the
filtering after basename guided rename detection again. So, I have this
series of patches structured to do the irrelevant filtering last to
start to show how much extra it costs, and then add relevant filtering
in to find_basename_matches() to show how much it speeds things up.
Basically, it's a way to reinforce something that apparently was too
easy to forget, and make sure the commit messages record this lesson.
Second, the items in the "relevant_sources" in this patch series will
include all sources that *might be* relevant. It has to be conservative
and catch anything that might need a rename, but in the patch series
after this one we'll find ways to weed out more of the *might be*
relevant ones. Unfortunately, merge-ort does not have sufficient
information to weed those ones out, and there isn't enough information
at the time of filtering exact renames out to remove the extra ones
either. It has to be deferred. So the deferral is in part to simplify
some later additions.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 552955ed7f ("clone: use more conventional config/option layering",
2020-10-01), clone learned to read configuration options earlier in its
execution, before creating the new repository. However, that led to a
problem: if the core.bare setting is set to false in the global config,
cloning a bare repository segfaults. This happens because the
repository is falsely thought to be non-bare, but clone has set the work
tree to NULL, which is then dereferenced.
The code to initialize the repository already considers the fact that a
user might want to override the --bare option for git init, but it
doesn't take into account clone, which uses a different option. Let's
just check that the work tree is not NULL, since that's how clone
indicates that the repository is bare. This is also the case for git
init, so we won't be regressing that case.
Reported-by: Joseph Vusich <jvusich@amazon.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When checking whether a commit was rewritten to a single object id, we
use a glob that insists on a 40-hex result. This works for sha1, but
fails t7003 when run with GIT_TEST_DEFAULT_HASH=sha256.
Since the previous commit simplified the case statement here, we only
have two arms: an empty string or a single object id. We can just loosen
our glob to match anything, and still distinguish those cases (we lose
the ability to notice bogus input, but that's not a problem; we are the
one who wrote the map in the first place, and anyway update-ref will
complain loudly if the input isn't a valid hash).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a ref maps to a commit that is neither rewritten nor kept by
filter-branch (e.g., because it was eliminated by rev-list's pathspec
selection), we rewrite it to its nearest ancestor.
Since the initial commit in 6f6826c52b (Add git-filter-branch,
2007-06-03), we have warned when there are multiple such ancestors in
the map file. However, the warning code is impossible to trigger these
days. Since a0e46390d3 (filter-branch: fix ref rewriting with
--subdirectory-filter, 2008-08-12), we find the ancestor using "rev-list
-1", so it can only ever have a single value.
This code is made doubly confusing by the fact that we append to the map
file when mapping ancestors. However, this can never yield multiple
values because:
- we explicitly check whether the map already exists, and if so, do
nothing (so our "append" will always be to a file that does not
exist)
- even if we were to try mapping twice, the process to do so is
deterministic. I.e., we'd always end up with the same ancestor for a
given sha1. So warning about it would be pointless; there is no
ambiguity.
So swap out the warning code for a BUG (which we'll simplify further in
the next commit). And let's stop using the append operator to make the
ancestor-mapping code less confusing.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
After it has rewritten all of the commits, filter-branch will then
rewrite each of the input refs based on the resulting map of old/new
commits. But we don't have any explicit test coverage of this code.
Let's make sure we are covering each of those cases:
- deleting a ref when all of its commits were pruned
- rewriting a ref based on the mapping (this happens throughout the
script, but let's make sure we generate the correct messages)
- rewriting a ref whose tip was excluded, in which case we rewrite to
the nearest ancestor. Note in this case that we still insist that no
"warning" line is present (even though it looks like we'd trigger
the "... was rewritten into multiple commits" one). See the next
commit for more details.
Note these all pass currently, but the latter two will fail when run
with GIT_TEST_DEFAULT_HASH=sha256.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code to fsck objects received across multiple packs during a
single git fetch session has been broken when the packfile URI
feature was in use. A workaround has been added by disabling the
codepath to avoid keeping a packfile that is too small.
* jt/transfer-fsck-across-packs-fix:
fetch-pack: do not mix --pack_header and packfile uri
Clang no longer produces a libFuzzer.a. Instead, you can include
libFuzzer by using -fsanitize=fuzzer. Therefore we should use that in
the example command for building fuzzers.
We also add -fsanitize=fuzzer-no-link to the CFLAGS to ensure that all
the required instrumentation is added when compiling git [1], and remove
-fsanitize-coverage=trace-pc-guard as it is deprecated.
I happen to have tested with LLVM 11 - however -fsanitize=fuzzer appears
to work in a wide range of reasonably modern clangs.
(On my system: what used to be libFuzzer.a now lives under the following
path, which is tricky albeit not impossible for a novice such as myself
to find:
/usr/lib64/clang/11.0.0/lib/linux/libclang_rt.fuzzer-x86_64.a )
[1] https://releases.llvm.org/11.0.0/docs/LibFuzzer.html#fuzzer-usage
Signed-off-by: Andrzej Hunt <ajrhunt@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pass the number of elements first and ther size second, as expected
by xcalloc(). Provide a semantic patch, which was actually used to
generate the rest of this patch.
The semantic patch would generate flip-flop diffs if both arguments
are sizeofs. We don't have such a case, and it's hard to imagine
the usefulness of such an allocation. If it ever occurs then we
could deal with it by duplicating the rule in the semantic patch to
make it cancel itself out, or we could change the code to use
CALLOC_ARRAY.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
