setup_git_directory_1(): avoid changing global state
For historical reasons, Git searches for the .git/ directory (or the
.git file) by changing the working directory successively to the parent
directory of the current directory, until either anything was found or
until a ceiling or a mount point is hit.
Further global state may be changed in case a .git/ directory was found.
We do have a use case, though, where we would like to find the .git/
directory without having any global state touched, though: when we read
the early config e.g. for the pager or for alias expansion.
Let's just move all of code that changes any global state out of the
function `setup_git_directory_gently_1()` into
`setup_git_directory_gently()`.
In subsequent patches, we will use the _1() function in a new
`discover_git_directory()` function that we will then use for the early
config code.
Note: the new loop is a *little* tricky, as we have to handle the root
directory specially: we cannot simply strip away the last component
including the slash, as the root directory only has that slash. To remedy
that, we introduce the `min_offset` variable that holds the minimal length
of an absolute path, and using that to special-case the root directory,
including an early exit before trying to find the parent of the root
directory.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/setup.c b/setup.c
index 20a1f0f..27a31de 100644
--- a/setup.c
+++ b/setup.c
@@ -818,22 +818,119 @@ static int canonicalize_ceiling_entry(struct string_list_item *item,
}
}
+enum discovery_result {
+ GIT_DIR_NONE = 0,
+ GIT_DIR_EXPLICIT,
+ GIT_DIR_DISCOVERED,
+ GIT_DIR_BARE,
+ /* these are errors */
+ GIT_DIR_HIT_CEILING = -1,
+ GIT_DIR_HIT_MOUNT_POINT = -2
+};
+
/*
* We cannot decide in this function whether we are in the work tree or
* not, since the config can only be read _after_ this function was called.
+ *
+ * Also, we avoid changing any global state (such as the current working
+ * directory) to allow early callers.
+ *
+ * The directory where the search should start needs to be passed in via the
+ * `dir` parameter; upon return, the `dir` buffer will contain the path of
+ * the directory where the search ended, and `gitdir` will contain the path of
+ * the discovered .git/ directory, if any. If `gitdir` is not absolute, it
+ * is relative to `dir` (i.e. *not* necessarily the cwd).
*/
-static const char *setup_git_directory_gently_1(int *nongit_ok)
+static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
+ struct strbuf *gitdir)
{
const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
- static struct strbuf cwd = STRBUF_INIT;
- const char *gitdirenv, *ret;
- char *gitfile;
- int offset, offset_parent, ceil_offset = -1;
+ const char *gitdirenv;
+ int ceil_offset = -1, min_offset = has_dos_drive_prefix(dir->buf) ? 3 : 1;
dev_t current_device = 0;
int one_filesystem = 1;
/*
+ * If GIT_DIR is set explicitly, we're not going
+ * to do any discovery, but we still do repository
+ * validation.
+ */
+ gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
+ if (gitdirenv) {
+ strbuf_addstr(gitdir, gitdirenv);
+ return GIT_DIR_EXPLICIT;
+ }
+
+ if (env_ceiling_dirs) {
+ int empty_entry_found = 0;
+
+ string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
+ filter_string_list(&ceiling_dirs, 0,
+ canonicalize_ceiling_entry, &empty_entry_found);
+ ceil_offset = longest_ancestor_length(dir->buf, &ceiling_dirs);
+ string_list_clear(&ceiling_dirs, 0);
+ }
+
+ if (ceil_offset < 0)
+ ceil_offset = min_offset - 2;
+
+ /*
+ * Test in the following order (relative to the dir):
+ * - .git (file containing "gitdir: <path>")
+ * - .git/
+ * - ./ (bare)
+ * - ../.git
+ * - ../.git/
+ * - ../ (bare)
+ * - ../../.git/
+ * etc.
+ */
+ one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
+ if (one_filesystem)
+ current_device = get_device_or_die(dir->buf, NULL, 0);
+ for (;;) {
+ int offset = dir->len;
+
+ 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;
+ strbuf_setlen(dir, offset);
+ if (gitdirenv) {
+ strbuf_addstr(gitdir, gitdirenv);
+ return GIT_DIR_DISCOVERED;
+ }
+
+ if (is_git_directory(dir->buf)) {
+ strbuf_addstr(gitdir, ".");
+ return GIT_DIR_BARE;
+ }
+
+ if (offset <= min_offset)
+ return GIT_DIR_HIT_CEILING;
+
+ while (--offset > ceil_offset && !is_dir_sep(dir->buf[offset]))
+ ; /* continue */
+ if (offset <= ceil_offset)
+ return GIT_DIR_HIT_CEILING;
+
+ strbuf_setlen(dir, offset > min_offset ? offset : min_offset);
+ if (one_filesystem &&
+ current_device != get_device_or_die(dir->buf, NULL, offset))
+ return GIT_DIR_HIT_MOUNT_POINT;
+ }
+}
+
+const char *setup_git_directory_gently(int *nongit_ok)
+{
+ static struct strbuf cwd = STRBUF_INIT;
+ struct strbuf dir = STRBUF_INIT, gitdir = STRBUF_INIT;
+ const char *prefix;
+
+ /*
* We may have read an incomplete configuration before
* setting-up the git directory. If so, clear the cache so
* that the next queries to the configuration reload complete
@@ -852,100 +949,43 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
if (strbuf_getcwd(&cwd))
die_errno(_("Unable to read current working directory"));
- offset = cwd.len;
+ strbuf_addbuf(&dir, &cwd);
- /*
- * If GIT_DIR is set explicitly, we're not going
- * to do any discovery, but we still do repository
- * validation.
- */
- gitdirenv = getenv(GIT_DIR_ENVIRONMENT);
- if (gitdirenv)
- return setup_explicit_git_dir(gitdirenv, &cwd, nongit_ok);
-
- if (env_ceiling_dirs) {
- int empty_entry_found = 0;
-
- string_list_split(&ceiling_dirs, env_ceiling_dirs, PATH_SEP, -1);
- filter_string_list(&ceiling_dirs, 0,
- canonicalize_ceiling_entry, &empty_entry_found);
- ceil_offset = longest_ancestor_length(cwd.buf, &ceiling_dirs);
- string_list_clear(&ceiling_dirs, 0);
+ switch (setup_git_directory_gently_1(&dir, &gitdir)) {
+ case GIT_DIR_NONE:
+ prefix = NULL;
+ break;
+ case GIT_DIR_EXPLICIT:
+ prefix = setup_explicit_git_dir(gitdir.buf, &cwd, nongit_ok);
+ break;
+ case GIT_DIR_DISCOVERED:
+ if (dir.len < cwd.len && chdir(dir.buf))
+ die(_("Cannot change to '%s'"), dir.buf);
+ prefix = setup_discovered_git_dir(gitdir.buf, &cwd, dir.len,
+ nongit_ok);
+ break;
+ case GIT_DIR_BARE:
+ if (dir.len < cwd.len && chdir(dir.buf))
+ die(_("Cannot change to '%s'"), dir.buf);
+ prefix = setup_bare_git_dir(&cwd, dir.len, nongit_ok);
+ break;
+ case GIT_DIR_HIT_CEILING:
+ prefix = setup_nongit(cwd.buf, nongit_ok);
+ break;
+ case GIT_DIR_HIT_MOUNT_POINT:
+ if (nongit_ok) {
+ *nongit_ok = 1;
+ strbuf_release(&cwd);
+ strbuf_release(&dir);
+ return NULL;
+ }
+ die(_("Not a git repository (or any parent up to mount point %s)\n"
+ "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
+ dir.buf);
+ default:
+ die("BUG: unhandled setup_git_directory_1() result");
}
- if (ceil_offset < 0 && has_dos_drive_prefix(cwd.buf))
- ceil_offset = 1;
-
- /*
- * Test in the following order (relative to the cwd):
- * - .git (file containing "gitdir: <path>")
- * - .git/
- * - ./ (bare)
- * - ../.git
- * - ../.git/
- * - ../ (bare)
- * - ../../.git/
- * etc.
- */
- one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
- if (one_filesystem)
- current_device = get_device_or_die(".", NULL, 0);
- for (;;) {
- gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
- if (gitfile)
- gitdirenv = gitfile = xstrdup(gitfile);
- else {
- if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
- gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
- }
-
- if (gitdirenv) {
- ret = setup_discovered_git_dir(gitdirenv,
- &cwd, offset,
- nongit_ok);
- free(gitfile);
- return ret;
- }
- free(gitfile);
-
- if (is_git_directory("."))
- return setup_bare_git_dir(&cwd, offset, nongit_ok);
-
- offset_parent = offset;
- while (--offset_parent > ceil_offset &&
- !is_dir_sep(cwd.buf[offset_parent]))
- ; /* continue */
- if (offset_parent <= ceil_offset)
- return setup_nongit(cwd.buf, nongit_ok);
- if (one_filesystem) {
- dev_t parent_device = get_device_or_die("..", cwd.buf,
- offset);
- if (parent_device != current_device) {
- if (nongit_ok) {
- if (chdir(cwd.buf))
- die_errno(_("Cannot come back to cwd"));
- *nongit_ok = 1;
- return NULL;
- }
- strbuf_setlen(&cwd, offset);
- die(_("Not a git repository (or any parent up to mount point %s)\n"
- "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
- cwd.buf);
- }
- }
- if (chdir("..")) {
- strbuf_setlen(&cwd, offset);
- die_errno(_("Cannot change to '%s/..'"), cwd.buf);
- }
- offset = offset_parent;
- }
-}
-
-const char *setup_git_directory_gently(int *nongit_ok)
-{
- const char *prefix;
-
- prefix = setup_git_directory_gently_1(nongit_ok);
if (prefix)
setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
else
@@ -954,6 +994,9 @@ const char *setup_git_directory_gently(int *nongit_ok)
startup_info->have_repository = !nongit_ok || !*nongit_ok;
startup_info->prefix = prefix;
+ strbuf_release(&dir);
+ strbuf_release(&gitdir);
+
return prefix;
}
