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[PATCH v2 8/8] Use the early config machinery to expand aliases

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Jun 8, 2017, 19:53 UTC
Message-ID
<af40ce088de03130a5edfae187bb8274b5a9d3a9.1496951503.git.johannes.schindelin@gmx.de>
In-Reply-To
<cover.1496951503.git.johannes.schindelin@gmx.de>

We already taught alias_lookup() to use the early config if the .git/ directory was not yet discovered, of course, however, since we called setup_git_directory_gently() before expanding the alias (if any), we only used the early config code path only if outside of any Git-managed directory.

With this commit, we finally switch over to really using the early config code path.

Rather than just chdir()ing into the indicated directory in case of an alias expanding to a shell command, we simply set up the .git/ directory so that e.g. GIT_PREFIX is set as expected.

This change also fixes a known issue where Git tried to read the pager config from an incorrect path in a subdirectory of a Git worktree if an alias expanded to a shell command.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 git.c            | 59 +++++++-------------------------------------------------
 t/t7006-pager.sh |  2 +-
 2 files changed, 8 insertions(+), 53 deletions(-)
diff --git a/git.c b/git.c
index 4163beaead4..6511595d467 100644
--- a/git.c
+++ b/git.c
@@ -16,50 +16,6 @@ const char git_more_info_string[] =
 	   "to read about a specific subcommand or concept.");
 
 static int use_pager = -1;
-static char *orig_cwd;
-static const char *env_names[] = {
-	GIT_DIR_ENVIRONMENT,
-	GIT_WORK_TREE_ENVIRONMENT,
-	GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
-	GIT_PREFIX_ENVIRONMENT
-};
-static char *orig_env[4];
-static int save_restore_env_balance;
-
-static void save_env_before_alias(void)
-{
-	int i;
-
-	assert(save_restore_env_balance == 0);
-	save_restore_env_balance = 1;
-	orig_cwd = xgetcwd();
-	for (i = 0; i < ARRAY_SIZE(env_names); i++) {
-		orig_env[i] = getenv(env_names[i]);
-		orig_env[i] = xstrdup_or_null(orig_env[i]);
-	}
-}
-
-static void restore_env(int external_alias)
-{
-	int i;
-
-	assert(save_restore_env_balance == 1);
-	save_restore_env_balance = 0;
-	if (!external_alias && orig_cwd && chdir(orig_cwd))
-		die_errno("could not move to %s", orig_cwd);
-	free(orig_cwd);
-	for (i = 0; i < ARRAY_SIZE(env_names); i++) {
-		if (external_alias &&
-		    !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
-			continue;
-		if (orig_env[i]) {
-			setenv(env_names[i], orig_env[i], 1);
-			free(orig_env[i]);
-		} else {
-			unsetenv(env_names[i]);
-		}
-	}
-}
 
 static void commit_pager_choice(void) {
 	switch (use_pager) {
@@ -245,36 +201,37 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 
 static int handle_alias(int *argcp, const char ***argv)
 {
+	struct strbuf cdup_dir = STRBUF_INIT;
 	int envchanged = 0, ret = 0, saved_errno = errno;
 	int count, option_count;
 	const char **new_argv;
 	const char *alias_command;
 	char *alias_string;
-	int unused_nongit;
-
-	save_env_before_alias();
-	setup_git_directory_gently(&unused_nongit);
 
 	alias_command = (*argv)[0];
-	alias_string = alias_lookup(alias_command, NULL);
+	alias_string = alias_lookup(alias_command, &cdup_dir);
 	if (alias_string) {
 		if (alias_string[0] == '!') {
 			struct child_process child = CHILD_PROCESS_INIT;
 
+			if (cdup_dir.len)
+				setup_git_directory();
+
 			commit_pager_choice();
-			restore_env(1);
 
 			child.use_shell = 1;
 			argv_array_push(&child.args, alias_string + 1);
 			argv_array_pushv(&child.args, (*argv) + 1);
 
 			ret = run_command(&child);
+			strbuf_release(&cdup_dir);
 			if (ret >= 0)   /* normal exit */
 				exit(ret);
 
 			die_errno("While expanding alias '%s': '%s'",
 			    alias_command, alias_string + 1);
 		}
+		strbuf_release(&cdup_dir);
 		count = split_cmdline(alias_string, &new_argv);
 		if (count < 0)
 			die("Bad alias.%s string: %s", alias_command,
@@ -308,8 +265,6 @@ static int handle_alias(int *argcp, const char ***argv)
 		ret = 1;
 	}
 
-	restore_env(0);
-
 	errno = saved_errno;
 
 	return ret;
diff --git a/t/t7006-pager.sh b/t/t7006-pager.sh
index 83881ec3a0c..20b4d83c281 100755
--- a/t/t7006-pager.sh
+++ b/t/t7006-pager.sh
@@ -391,7 +391,7 @@ test_expect_success TTY 'core.pager in repo config works and retains cwd' '
 	)
 '
 
-test_expect_failure TTY 'core.pager is found via alias in subdirectory' '
+test_expect_success TTY 'core.pager is found via alias in subdirectory' '
 	sane_unset GIT_PAGER &&
 	test_config core.pager "cat >via-alias" &&
 	(

-- 
2.13.0.windows.1.460.g13f583bedb5
Previous: Johannes SchindelinNext: Jeff King
Message 17 of 32 in “Avoid problem where git_dir is set after alias expansion”
  1. 0/8 Avoid problem where git_dir is set after alias expansionJohannes Schindelin, Jun 8, 2017
  2. 2/8 config: report correct line number upon errorJohannes Schindelin, Jun 8, 2017
  3. Jeff KingJun 10, 2017
  4. Johannes SchindelinJun 13, 2017
  5. Jeff KingJun 13, 2017
  6. 4/8 read_early_config(): optionally return the worktree's top-level directoryJohannes Schindelin, Jun 8, 2017
  7. Jeff KingJun 10, 2017
  8. 1/8 discover_git_directory(): avoid setting invalid git_dirJohannes Schindelin, Jun 8, 2017
  9. Jeff KingJun 10, 2017
  10. 3/8 help: use early config when autocorrecting aliasesJohannes Schindelin, Jun 8, 2017
  11. Jeff KingJun 10, 2017
  12. 5/8 t1308: relax the test verifying that empty alias values are disallowedJohannes Schindelin, Jun 8, 2017
  13. Junio C HamanoJun 10, 2017
  14. Johannes SchindelinJun 13, 2017
  15. Junio C HamanoJun 13, 2017
  16. 6/8 t7006: demonstrate a problem with aliases in subdirectoriesJohannes Schindelin, Jun 8, 2017
  17. 8/8 Use the early config machinery to expand aliasesJohannes Schindelin, Jun 8, 2017
  18. Jeff KingJun 10, 2017
  19. Jeff KingJun 10, 2017
  20. Junio C HamanoJun 12, 2017
  21. Johannes SchindelinJun 13, 2017
  22. Jeff KingJun 13, 2017
  23. 7/8 alias_lookup(): optionally return top-level directoryJohannes Schindelin, Jun 8, 2017
  24. Jeff KingJun 10, 2017
  25. Johannes SchindelinJun 13, 2017
  26. Jeff KingJun 13, 2017
  27. Johannes SchindelinJun 13, 2017
  28. Jeff KingJun 13, 2017
  29. Junio C HamanoJun 13, 2017
  30. Jeff KingJun 14, 2017
  31. Johannes SchindelinJun 14, 2017
  32. Brandon WilliamsJun 8, 2017

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