| Message ID | pull.1134.v2.git.git.1637041986945.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] sequencer: do not export GIT_DIR and GIT_WORK_TREE for 'exec' | expand |
On Tue, Nov 16, 2021 at 05:53:06AM +0000, Elijah Newren via GitGitGadget wrote: > sequencer: fix environment that 'exec' commands run under > > Changes since v1: > > * Fix wording in multiple locations pointed out by Johannes > Altmanninger > > Note that Johaness Altmanninger also suggested some additional > GIT_DIR/GIT_WORK_TREE and --git-dir/--work-tree testcases, but since > those change the current working directory to the work tree so that > GIT_WORK_TREE ends up being '.' in every case, I think it's straying a > bit from the point of the test. If other feel strongly, I can add them > in. Yeah I also think it's better to leave them out for now. For one, the GIT_DIR/GIT_WORK_TREE test is not really interesting. Next, things are not so obivous: I'm not sure if --git-dir/--work-tree should export those variables to exec but that can be investigated later. This patch looks great.
Hi Elijah On 16/11/2021 05:53, Elijah Newren via GitGitGadget wrote: > From: Elijah Newren <newren@gmail.com> > > 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. Thanks for fixing this. The commit message does a great job of explaining the problem and how we got there. The patch looks fine to me though I think all the exec tests live in t3404 (interactive and non interactive) so it feels a bit strange to add a new test file just for this. There are plenty of uses of --exec in other test files but I think they are just using the exec command as part of the test rather than testing the --exec functionality (with the exception of t3418 which tests --reschedule-failed-exec) Best Wishes Phillip > Signed-off-by: Elijah Newren <newren@gmail.com> > Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de> > --- > sequencer: fix environment that 'exec' commands run under > > Changes since v1: > > * Fix wording in multiple locations pointed out by Johannes > Altmanninger > > Note that Johaness Altmanninger also suggested some additional > GIT_DIR/GIT_WORK_TREE and --git-dir/--work-tree testcases, but since > those change the current working directory to the work tree so that > GIT_WORK_TREE ends up being '.' in every case, I think it's straying a > bit from the point of the test. If other feel strongly, I can add them > in. > > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1134%2Fnewren%2Ffix-rebase-exec-environ-v2 > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1134/newren/fix-rebase-exec-environ-v2 > Pull-Request: https://github.com/git/git/pull/1134 > > Range-diff vs v1: > > 1: 12713c83705 ! 1: c647c45375a sequencer: fix environment that 'exec' commands run under > @@ Metadata > Author: Elijah Newren <newren@gmail.com> > > ## Commit message ## > - sequencer: fix environment that 'exec' commands run under > + 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 > @@ Commit message > masked the particular bug observed without fixing the real underlying > problem. > > - 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: > + 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 > @@ Commit message > 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 were in 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 > + 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 > @@ Commit message > export. > > Each of the above problems would have been fixed automatically when > - git-rebase become a full builtin, had it not been for the fact that > + 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. > > > > sequencer.c | 9 +-------- > t/t3409-rebase-environ.sh | 23 +++++++++++++++++++++++ > 2 files changed, 24 insertions(+), 8 deletions(-) > create mode 100755 t/t3409-rebase-environ.sh > > diff --git a/sequencer.c b/sequencer.c > index ea96837cde3..9afdbe3e3d1 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -3495,17 +3495,12 @@ static int error_failed_squash(struct repository *r, > > static int do_exec(struct repository *r, const char *command_line) > { > - struct strvec child_env = STRVEC_INIT; > const char *child_argv[] = { NULL, NULL }; > int dirty, status; > > fprintf(stderr, _("Executing: %s\n"), command_line); > child_argv[0] = command_line; > - strvec_pushf(&child_env, "GIT_DIR=%s", absolute_path(get_git_dir())); > - strvec_pushf(&child_env, "GIT_WORK_TREE=%s", > - absolute_path(get_git_work_tree())); > - status = run_command_v_opt_cd_env(child_argv, RUN_USING_SHELL, NULL, > - child_env.v); > + status = run_command_v_opt(child_argv, RUN_USING_SHELL); > > /* force re-reading of the cache */ > if (discard_index(r->index) < 0 || repo_read_index(r) < 0) > @@ -3535,8 +3530,6 @@ static int do_exec(struct repository *r, const char *command_line) > status = 1; > } > > - strvec_clear(&child_env); > - > return status; > } > > diff --git a/t/t3409-rebase-environ.sh b/t/t3409-rebase-environ.sh > new file mode 100755 > index 00000000000..83ffb39d9ff > --- /dev/null > +++ b/t/t3409-rebase-environ.sh > @@ -0,0 +1,23 @@ > +#!/bin/sh > + > +test_description='git rebase interactive environment' > + > +. ./test-lib.sh > + > +test_expect_success 'setup' ' > + test_commit one && > + test_commit two && > + test_commit three > +' > + > +test_expect_success 'rebase --exec does not muck with GIT_DIR' ' > + git rebase --exec "printf %s \$GIT_DIR >environ" HEAD~1 && > + test_must_be_empty environ > +' > + > +test_expect_success 'rebase --exec does not muck with GIT_WORK_TREE' ' > + git rebase --exec "printf %s \$GIT_WORK_TREE >environ" HEAD~1 && > + test_must_be_empty environ > +' > + > +test_done > > base-commit: 88d915a634b449147855041d44875322de2b286d >
diff --git a/sequencer.c b/sequencer.c index ea96837cde3..9afdbe3e3d1 100644 --- a/sequencer.c +++ b/sequencer.c @@ -3495,17 +3495,12 @@ static int error_failed_squash(struct repository *r, static int do_exec(struct repository *r, const char *command_line) { - struct strvec child_env = STRVEC_INIT; const char *child_argv[] = { NULL, NULL }; int dirty, status; fprintf(stderr, _("Executing: %s\n"), command_line); child_argv[0] = command_line; - strvec_pushf(&child_env, "GIT_DIR=%s", absolute_path(get_git_dir())); - strvec_pushf(&child_env, "GIT_WORK_TREE=%s", - absolute_path(get_git_work_tree())); - status = run_command_v_opt_cd_env(child_argv, RUN_USING_SHELL, NULL, - child_env.v); + status = run_command_v_opt(child_argv, RUN_USING_SHELL); /* force re-reading of the cache */ if (discard_index(r->index) < 0 || repo_read_index(r) < 0) @@ -3535,8 +3530,6 @@ static int do_exec(struct repository *r, const char *command_line) status = 1; } - strvec_clear(&child_env); - return status; } diff --git a/t/t3409-rebase-environ.sh b/t/t3409-rebase-environ.sh new file mode 100755 index 00000000000..83ffb39d9ff --- /dev/null +++ b/t/t3409-rebase-environ.sh @@ -0,0 +1,23 @@ +#!/bin/sh + +test_description='git rebase interactive environment' + +. ./test-lib.sh + +test_expect_success 'setup' ' + test_commit one && + test_commit two && + test_commit three +' + +test_expect_success 'rebase --exec does not muck with GIT_DIR' ' + git rebase --exec "printf %s \$GIT_DIR >environ" HEAD~1 && + test_must_be_empty environ +' + +test_expect_success 'rebase --exec does not muck with GIT_WORK_TREE' ' + git rebase --exec "printf %s \$GIT_WORK_TREE >environ" HEAD~1 && + test_must_be_empty environ +' + +test_done