From 434e0636db102cd89292ea28e8e947fa6e790b23 Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Sat, 4 Dec 2021 05:36:59 +0000 Subject: 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 Acked-by: Johannes Schindelin Acked-by: Johannes Altmanninger Acked-by: Phillip Wood Signed-off-by: Junio C Hamano diff --git a/sequencer.c b/sequencer.c index ea96837..9afdbe3 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 0000000..83ffb39 --- /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 -- cgit v0.10.2-6-g49f6