Commit graph

2 commits

Author SHA1 Message Date
Ævar Arnfjörð Bjarmason
b6046abc0c built-ins & libs & helpers: add/move destructors, fix leaks
Fix various leaks in built-ins, libraries and a test helper here we
were missing a call to strbuf_release(), string_list_clear() etc, or
were calling them after a potential "return".

Comments on individual changes:

- builtin/checkout.c: Fix a memory leak that was introduced in [1]. A
  sibling leak introduced in [2] was recently fixed in [3]. As with [3]
  we should be using the wt_status_state_free_buffers() API introduced
  in [4].

- builtin/repack.c: Fix a leak that's been here since this use of
  "strbuf_release()" was added in a1bbc6c017 (repack: rewrite the shell
  script in C, 2013-09-15). We don't use the variable for anything
  except this loop, so we can instead free it right afterwards.

- builtin/rev-parse: Fix a leak that's been here since this code was
  added in 21d4783538 (Add a parseopt mode to git-rev-parse to bring
  parse-options to shell scripts., 2007-11-04).

- builtin/stash.c: Fix a couple of leaks that have been here since
  this code was added in d4788af875 (stash: convert create to builtin,
  2019-02-25), we strbuf_release()'d only some of the "struct strbuf" we
  allocated earlier in the function, let's release all of them.

- ref-filter.c: Fix a leak in 482c119186 (gpg-interface: improve
  interface for parsing tags, 2021-02-11), we don't use the "payload"
  variable that we ask parse_signature() to populate for us, so let's
  free it.

- t/helper/test-fake-ssh.c: Fix a leak that's been here since this
  code was added in 3064d5a38c (mingw: fix t5601-clone.sh,
  2016-01-27). Let's free the "struct strbuf" as soon as we don't need
  it anymore.

1. c45f0f525d (switch: reject if some operation is in progress,
   2019-03-29)
2. 2708ce62d2 (branch: sort detached HEAD based on a flag,
   2021-01-07)
3. abcac2e19f (ref-filter.c: fix a leak in get_head_description,
   2022-09-25)
4. 962dd7ebc3 (wt-status: introduce wt_status_state_free_buffers(),
   2020-09-27).

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2022-11-21 12:32:48 +09:00
Elijah Newren
434e0636db sequencer: do not export GIT_DIR and GIT_WORK_TREE for 'exec'
Commands executed from `git rebase --exec` can give different behavior
from within that environment than they would outside of it, due to the
fact that sequencer.c exports both GIT_DIR and GIT_WORK_TREE.  For
example, if the relevant script calls something like

  git -C ../otherdir log --format=%H --no-walk

the user may be surprised to find that the command above does not show a
commit hash from ../otherdir, because $GIT_DIR prevents automatic gitdir
detection and makes the -C option useless.

This is a regression in behavior from the original legacy
implemented-in-shell rebase.  It is perhaps rare for it to cause
problems in practice, especially since most small problems that were
caused by this area of bugs has been fixed-up in the past in a way that
masked the particular bug observed without fixing the real underlying
problem.

An explanation of how we arrived at the current situation is perhaps
merited.  The setting of GIT_DIR and GIT_WORK_TREE done by sequencer.c
arose from a sequence of historical accidents:

* When rebase was implemented as a shell command, it would call
  git-sh-setup, which among other things would set GIT_DIR -- but not
  export it.  This meant that when rebase --exec commands were run via
      /bin/sh -c "$COMMAND"
  they would not inherit the GIT_DIR setting.  The fact that GIT_DIR
  was not set in the run $COMMAND is the behavior we'd like to restore.

* When the rebase--helper builtin was introduced to allow incrementally
  replacing shell with C code, we had an implementation that was half
  shell, half C.  In particular, commit 18633e1a22 ("rebase -i: use the
  rebase--helper builtin", 2017-02-09) added calls to
      exec git rebase--helper ...
  which caused rebase--helper to inherit the GIT_DIR environment
  variable from the shell.  git's setup would change the environment
  variable from an absolute path to a relative one (".git"), but would
  leave it set.  This meant that when rebase --exec commands were run
  via
      run_command_v_opt(...)
  they would inherit the GIT_DIR setting.

* In commit 09d7b6c6fa ("sequencer: pass absolute GIT_DIR to exec
  commands", 2017-10-31), it was noted that the GIT_DIR caused problems
  with some commands; e.g.
      git rebase --exec 'cd subdir && git describe' ...
  would have GIT_DIR=.git which was invalid due to the change to the
  subdirectory.  Instead of questioning why GIT_DIR was set, that commit
  instead made sequencer change GIT_DIR to be an absolute path and
  explicitly export it via
      argv_array_pushf(&child_env, "GIT_DIR=%s", absolute_path(get_git_dir()));
      run_command_v_opt_cd_env(..., child_env.argv)

* In commit ab5e67d751 ("sequencer: pass absolute GIT_WORK_TREE to exec
  commands", 2018-07-14), it was noted that when GIT_DIR is set but
  GIT_WORK_TREE is not, that we do not discover GIT_WORK_TREE but just
  assume it is '.'.  That is incorrect if trying to run commands from a
  subdirectory.  However, rather than question why GIT_DIR was set, that
  commit instead also added GIT_WORK_TREE to the list of things to
  export.

Each of the above problems would have been fixed automatically when
git-rebase became a full builtin, had it not been for the fact that
sequencer.c started exporting GIT_DIR and GIT_WORK_TREE in the interim.
Stop exporting them now.

Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Altmanninger <aclopte@gmail.com>
Acked-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-04 23:41:05 -08:00