These patches are an attempt to make Git's startup sequence a bit less surprising. The idea here is to discover the .git/ directory gently (i.e. without changing the current working directory, nor any global variables), and to use it to read the .git/config file early, before we actually called setup_git_directory() (if we ever do that). This also allows us to fix the early config e.g. to determine the pager or to resolve aliases in a non-surprising manner. My own use case: in the GVFS Git fork, we need to execute pre-command and post-command hooks before and after *every* Git command. A previous version of the pre-command/post-command hook support was broken, as it used run_hook() which implicitly called setup_git_directory() too early. The discover_git_directory() function (and due to core.hooksPath also the read_early_config() function) helped me fix this. Notable notes: - Even if it can cause surprising problems, `init` and `clone` are not special-cased. Rationale: it would introduce technical debt and violate the Principle Of Least Astonishment. - The read_early_config() function does not cache Git directory discovery nor read values. This is left for another patch series, if it ever becomes necessary. - The alias handling in git.c could possibly benefit from this work, but again, this is a separate topic from the current patch series. Changes since v3: - instead of just fixing the `== '/'` comparison, 2/9 now *also* changes the style of the original to something Linux' checkpatch.pl prefers. - fixed the comment added in 8/9 which was stale from an earlier iteration of this patch series. - adjusted the commit above discover_git_directory()'s declaration, to make it more understandable. - touched up the commit message of 5/9 to make the flow more natural. - moved a fault fixup: by mistake, the repository_format check was added to 8/9 when it really needed to go to 5/9, where the discover_git_directory() function was introduced (I noticed this while rebasing). - fixed discover_git_directory() when setup_git_directory_gently_1() returned GIT_DIR_NONE (the previous iteration would *not* return NULL in that case). Johannes Schindelin (10): t7006: replace dubious test setup_git_directory(): use is_dir_sep() helper Prepare setup_discovered_git_directory() the root directory setup_git_directory_1(): avoid changing global state Introduce the discover_git_directory() function Make read_early_config() reusable read_early_config(): avoid .git/config hack when unneeded read_early_config(): really discover .git/ Test read_early_config() setup_git_directory_gently_1(): avoid die()ing cache.h | 8 ++ config.c | 25 +++++ pager.c | 31 ------ setup.c | 246 +++++++++++++++++++++++++++++++++--------------- t/helper/test-config.c | 15 +++ t/t1309-early-config.sh | 50 ++++++++++ t/t7006-pager.sh | 18 +++- 7 files changed, 282 insertions(+), 111 deletions(-) create mode 100755 t/t1309-early-config.sh base-commit: 3bc53220cb2dcf709f7a027a3f526befd021d858 Published-As: https://github.com/dscho/git/releases/tag/early-config-v4 Fetch-It-Via: git fetch https://github.com/dscho/git early-config-v4 Interdiff vs v3: diff --git a/cache.h b/cache.h index 8a4580f921d..e7b57457e73 100644 --- a/cache.h +++ b/cache.h @@ -518,7 +518,12 @@ extern void set_git_work_tree(const char *tree); #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES" extern void setup_work_tree(void); -/* Find GIT_DIR without changing the working directory or other global state */ +/* + * Find GIT_DIR of the repository that contains the current working directory, + * without changing the working directory or other global state. The result is + * appended to gitdir. The return value is either NULL if no repository was + * found, or pointing to the path inside gitdir's buffer. + */ extern const char *discover_git_directory(struct strbuf *gitdir); extern const char *setup_git_directory_gently(int *); extern const char *setup_git_directory(void); diff --git a/config.c b/config.c index 749623a9649..a88df53fdbc 100644 --- a/config.c +++ b/config.c @@ -1419,14 +1419,12 @@ void read_early_config(config_fn_t cb, void *data) git_config_with_options(cb, data, NULL, 1); /* - * When we are not about to create a repository ourselves (init or - * clone) and when no .git/ directory was set up yet (in which case - * git_config_with_options() would already have picked up the - * repository config), we ask discover_git_directory() to figure out - * whether there is any repository config we should use (but unlike + * When setup_git_directory() was not yet asked to discover the + * GIT_DIR, we ask discover_git_directory() to figure out whether there + * is any repository config we should use (but unlike * setup_git_directory_gently(), no global state is changed, most - * notably, the current working directory is still the same after - * the call). + * notably, the current working directory is still the same after the + * call). */ if (!have_git_dir() && discover_git_directory(&buf)) { struct git_config_source repo_config; diff --git a/setup.c b/setup.c index 5320ae37314..9118b48590a 100644 --- a/setup.c +++ b/setup.c @@ -825,7 +825,8 @@ enum discovery_result { GIT_DIR_BARE, /* these are errors */ GIT_DIR_HIT_CEILING = -1, - GIT_DIR_HIT_MOUNT_POINT = -2 + GIT_DIR_HIT_MOUNT_POINT = -2, + GIT_DIR_INVALID_GITFILE = -3 }; /* @@ -842,7 +843,8 @@ enum discovery_result { * `dir` (i.e. *not* necessarily the cwd). */ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir, - struct strbuf *gitdir) + struct strbuf *gitdir, + int die_on_error) { const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT); struct string_list ceiling_dirs = STRING_LIST_INIT_DUP; @@ -890,14 +892,22 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir, if (one_filesystem) current_device = get_device_or_die(dir->buf, NULL, 0); for (;;) { - int offset = dir->len; + int offset = dir->len, error_code = 0; if (offset > min_offset) strbuf_addch(dir, '/'); strbuf_addstr(dir, DEFAULT_GIT_DIR_ENVIRONMENT); - gitdirenv = read_gitfile(dir->buf); - if (!gitdirenv && is_git_directory(dir->buf)) - gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT; + gitdirenv = read_gitfile_gently(dir->buf, die_on_error ? + NULL : &error_code); + if (!gitdirenv) { + if (die_on_error || + error_code == READ_GITFILE_ERR_NOT_A_FILE) { + if (is_git_directory(dir->buf)) + gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT; + } else if (error_code && + error_code != READ_GITFILE_ERR_STAT_FAILED) + return GIT_DIR_INVALID_GITFILE; + } strbuf_setlen(dir, offset); if (gitdirenv) { strbuf_addstr(gitdir, gitdirenv); @@ -912,7 +922,8 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir, if (offset <= min_offset) return GIT_DIR_HIT_CEILING; - while (--offset > ceil_offset && !is_dir_sep(dir->buf[offset])); + while (--offset > ceil_offset && !is_dir_sep(dir->buf[offset])) + ; /* continue */ if (offset <= ceil_offset) return GIT_DIR_HIT_CEILING; @@ -933,7 +944,7 @@ const char *discover_git_directory(struct strbuf *gitdir) return NULL; cwd_len = dir.len; - if (setup_git_directory_gently_1(&dir, gitdir) < 0) { + if (setup_git_directory_gently_1(&dir, gitdir, 0) <= 0) { strbuf_release(&dir); return NULL; } @@ -963,7 +974,7 @@ const char *discover_git_directory(struct strbuf *gitdir) return NULL; } - return gitdir->buf; + return gitdir->buf + gitdir_offset; } const char *setup_git_directory_gently(int *nongit_ok) @@ -992,7 +1003,7 @@ const char *setup_git_directory_gently(int *nongit_ok) die_errno(_("Unable to read current working directory")); strbuf_addbuf(&dir, &cwd); - switch (setup_git_directory_gently_1(&dir, &gitdir)) { + switch (setup_git_directory_gently_1(&dir, &gitdir, 1)) { case GIT_DIR_NONE: prefix = NULL; break; -- 2.12.0.windows.1.7.g94dafc3b124