merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 184 insertions, 76 deletions

diff --git a/third_party/git/worktree.c b/third_party/git/worktree.c
index 5b4793caa3..f84ceae87d 100644
--- a/third_party/git/worktree.c
+++ b/third_party/git/worktree.c
@@ -21,7 +21,7 @@ void free_worktrees(struct worktree **worktrees)
 }
 
 /**
- * Update head_sha1, head_ref and is_detached of the given worktree
+ * Update head_oid, head_ref and is_detached of the given worktree
  */
 static void add_head_info(struct worktree *wt)
 {
@@ -47,14 +47,10 @@ static void add_head_info(struct worktree *wt)
 static struct worktree *get_main_worktree(void)
 {
 	struct worktree *worktree = NULL;
-	struct strbuf path = STRBUF_INIT;
 	struct strbuf worktree_path = STRBUF_INIT;
 
-	strbuf_add_absolute_path(&worktree_path, get_git_common_dir());
-	if (!strbuf_strip_suffix(&worktree_path, "/.git"))
-		strbuf_strip_suffix(&worktree_path, "/.");
-
-	strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
+	strbuf_add_real_path(&worktree_path, get_git_common_dir());
+	strbuf_strip_suffix(&worktree_path, "/.git");
 
 	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
@@ -68,9 +64,6 @@ static struct worktree *get_main_worktree(void)
 	worktree->is_bare = (is_bare_repository_cfg == 1) ||
 		is_bare_repository();
 	add_head_info(worktree);
-
-	strbuf_release(&path);
-	strbuf_release(&worktree_path);
 	return worktree;
 }
 
@@ -87,16 +80,8 @@ static struct worktree *get_linked_worktree(const char *id)
 	if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
 		/* invalid gitdir file */
 		goto done;
-
 	strbuf_rtrim(&worktree_path);
-	if (!strbuf_strip_suffix(&worktree_path, "/.git")) {
-		strbuf_reset(&worktree_path);
-		strbuf_add_absolute_path(&worktree_path, ".");
-		strbuf_strip_suffix(&worktree_path, "/.");
-	}
-
-	strbuf_reset(&path);
-	strbuf_addf(&path, "%s/worktrees/%s/HEAD", get_git_common_dir(), id);
+	strbuf_strip_suffix(&worktree_path, "/.git");
 
 	worktree = xcalloc(1, sizeof(*worktree));
 	worktree->path = strbuf_detach(&worktree_path, NULL);
@@ -126,14 +111,7 @@ static void mark_current_worktree(struct worktree **worktrees)
 	free(git_dir);
 }
 
-static int compare_worktree(const void *a_, const void *b_)
-{
-	const struct worktree *const *a = a_;
-	const struct worktree *const *b = b_;
-	return fspathcmp((*a)->path, (*b)->path);
-}
-
-struct worktree **get_worktrees(unsigned flags)
+struct worktree **get_worktrees(void)
 {
 	struct worktree **list = NULL;
 	struct strbuf path = STRBUF_INIT;
@@ -164,13 +142,6 @@ struct worktree **get_worktrees(unsigned flags)
 	ALLOC_GROW(list, counter + 1, alloc);
 	list[counter] = NULL;
 
-	if (flags & GWT_SORT_LINKED)
-		/*
-		 * don't sort the first item (main worktree), which will
-		 * always be the first
-		 */
-		QSORT(list + 1, counter - 1, compare_worktree);
-
 	mark_current_worktree(list);
 	return list;
 }
@@ -215,7 +186,6 @@ struct worktree *find_worktree(struct worktree **list,
 			       const char *arg)
 {
 	struct worktree *wt;
-	char *path;
 	char *to_free = NULL;
 
 	if ((wt = find_worktree_by_suffix(list, arg)))
@@ -223,19 +193,27 @@ struct worktree *find_worktree(struct worktree **list,
 
 	if (prefix)
 		arg = to_free = prefix_filename(prefix, arg);
-	path = real_pathdup(arg, 0);
-	if (!path) {
-		free(to_free);
+	wt = find_worktree_by_path(list, arg);
+	free(to_free);
+	return wt;
+}
+
+struct worktree *find_worktree_by_path(struct worktree **list, const char *p)
+{
+	struct strbuf wt_path = STRBUF_INIT;
+	char *path = real_pathdup(p, 0);
+
+	if (!path)
 		return NULL;
-	}
 	for (; *list; list++) {
-		const char *wt_path = real_path_if_valid((*list)->path);
+		if (!strbuf_realpath(&wt_path, (*list)->path, 0))
+			continue;
 
-		if (wt_path && !fspathcmp(path, wt_path))
+		if (!fspathcmp(path, wt_path.buf))
 			break;
 	}
 	free(path);
-	free(to_free);
+	strbuf_release(&wt_path);
 	return *list;
 }
 
@@ -284,6 +262,7 @@ int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
 		      unsigned flags)
 {
 	struct strbuf wt_path = STRBUF_INIT;
+	struct strbuf realpath = STRBUF_INIT;
 	char *path = NULL;
 	int err, ret = -1;
 
@@ -335,7 +314,8 @@ int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
 		goto done;
 	}
 
-	ret = fspathcmp(path, real_path(git_common_path("worktrees/%s", wt->id)));
+	strbuf_realpath(&realpath, git_common_path("worktrees/%s", wt->id), 1);
+	ret = fspathcmp(path, realpath.buf);
 
 	if (ret)
 		strbuf_addf_gently(errmsg, _("'%s' does not point back to '%s'"),
@@ -343,6 +323,7 @@ int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
 done:
 	free(path);
 	strbuf_release(&wt_path);
+	strbuf_release(&realpath);
 	return ret;
 }
 
@@ -371,13 +352,12 @@ int is_worktree_being_rebased(const struct worktree *wt,
 
 	memset(&state, 0, sizeof(state));
 	found_rebase = wt_status_check_rebase(wt, &state) &&
-		((state.rebase_in_progress ||
-		  state.rebase_interactive_in_progress) &&
-		 state.branch &&
-		 starts_with(target, "refs/heads/") &&
-		 !strcmp(state.branch, target + strlen("refs/heads/")));
-	free(state.branch);
-	free(state.onto);
+		       (state.rebase_in_progress ||
+			state.rebase_interactive_in_progress) &&
+		       state.branch &&
+		       skip_prefix(target, "refs/heads/", &target) &&
+		       !strcmp(state.branch, target);
+	wt_status_state_free_buffers(&state);
 	return found_rebase;
 }
 
@@ -385,15 +365,15 @@ int is_worktree_being_bisected(const struct worktree *wt,
 			       const char *target)
 {
 	struct wt_status_state state;
-	int found_rebase;
+	int found_bisect;
 
 	memset(&state, 0, sizeof(state));
-	found_rebase = wt_status_check_bisect(wt, &state) &&
-		state.branch &&
-		starts_with(target, "refs/heads/") &&
-		!strcmp(state.branch, target + strlen("refs/heads/"));
-	free(state.branch);
-	return found_rebase;
+	found_bisect = wt_status_check_bisect(wt, &state) &&
+		       state.branch &&
+		       skip_prefix(target, "refs/heads/", &target) &&
+		       !strcmp(state.branch, target);
+	wt_status_state_free_buffers(&state);
+	return found_bisect;
 }
 
 /*
@@ -411,7 +391,7 @@ const struct worktree *find_shared_symref(const char *symref,
 
 	if (worktrees)
 		free_worktrees(worktrees);
-	worktrees = get_worktrees(0);
+	worktrees = get_worktrees();
 
 	for (i = 0; worktrees[i]; i++) {
 		struct worktree *wt = worktrees[i];
@@ -449,7 +429,7 @@ const struct worktree *find_shared_symref(const char *symref,
 int submodule_uses_worktrees(const char *path)
 {
 	char *submodule_gitdir;
-	struct strbuf sb = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT, err = STRBUF_INIT;
 	DIR *dir;
 	struct dirent *d;
 	int ret = 0;
@@ -463,18 +443,16 @@ int submodule_uses_worktrees(const char *path)
 	get_common_dir_noenv(&sb, submodule_gitdir);
 	free(submodule_gitdir);
 
-	/*
-	 * The check below is only known to be good for repository format
-	 * version 0 at the time of writing this code.
-	 */
 	strbuf_addstr(&sb, "/config");
 	read_repository_format(&format, sb.buf);
-	if (format.version != 0) {
+	if (verify_repository_format(&format, &err)) {
+		strbuf_release(&err);
 		strbuf_release(&sb);
 		clear_repository_format(&format);
 		return 1;
 	}
 	clear_repository_format(&format);
+	strbuf_release(&err);
 
 	/* Replace config by worktrees. */
 	strbuf_setlen(&sb, sb.len - strlen("config"));
@@ -558,21 +536,13 @@ void strbuf_worktree_ref(const struct worktree *wt,
 	strbuf_addstr(sb, refname);
 }
 
-const char *worktree_ref(const struct worktree *wt, const char *refname)
-{
-	static struct strbuf sb = STRBUF_INIT;
-
-	strbuf_reset(&sb);
-	strbuf_worktree_ref(wt, &sb, refname);
-	return sb.buf;
-}
-
 int other_head_refs(each_ref_fn fn, void *cb_data)
 {
 	struct worktree **worktrees, **p;
+	struct strbuf refname = STRBUF_INIT;
 	int ret = 0;
 
-	worktrees = get_worktrees(0);
+	worktrees = get_worktrees();
 	for (p = worktrees; *p; p++) {
 		struct worktree *wt = *p;
 		struct object_id oid;
@@ -581,14 +551,152 @@ int other_head_refs(each_ref_fn fn, void *cb_data)
 		if (wt->is_current)
 			continue;
 
+		strbuf_reset(&refname);
+		strbuf_worktree_ref(wt, &refname, "HEAD");
 		if (!refs_read_ref_full(get_main_ref_store(the_repository),
-					worktree_ref(wt, "HEAD"),
+					refname.buf,
 					RESOLVE_REF_READING,
 					&oid, &flag))
-			ret = fn(worktree_ref(wt, "HEAD"), &oid, flag, cb_data);
+			ret = fn(refname.buf, &oid, flag, cb_data);
 		if (ret)
 			break;
 	}
 	free_worktrees(worktrees);
+	strbuf_release(&refname);
 	return ret;
 }
+
+/*
+ * Repair worktree's /path/to/worktree/.git file if missing, corrupt, or not
+ * pointing at <repo>/worktrees/<id>.
+ */
+static void repair_gitfile(struct worktree *wt,
+			   worktree_repair_fn fn, void *cb_data)
+{
+	struct strbuf dotgit = STRBUF_INIT;
+	struct strbuf repo = STRBUF_INIT;
+	char *backlink;
+	const char *repair = NULL;
+	int err;
+
+	/* missing worktree can't be repaired */
+	if (!file_exists(wt->path))
+		return;
+
+	if (!is_directory(wt->path)) {
+		fn(1, wt->path, _("not a directory"), cb_data);
+		return;
+	}
+
+	strbuf_realpath(&repo, git_common_path("worktrees/%s", wt->id), 1);
+	strbuf_addf(&dotgit, "%s/.git", wt->path);
+	backlink = xstrdup_or_null(read_gitfile_gently(dotgit.buf, &err));
+
+	if (err == READ_GITFILE_ERR_NOT_A_FILE)
+		fn(1, wt->path, _(".git is not a file"), cb_data);
+	else if (err)
+		repair = _(".git file broken");
+	else if (fspathcmp(backlink, repo.buf))
+		repair = _(".git file incorrect");
+
+	if (repair) {
+		fn(0, wt->path, repair, cb_data);
+		write_file(dotgit.buf, "gitdir: %s", repo.buf);
+	}
+
+	free(backlink);
+	strbuf_release(&repo);
+	strbuf_release(&dotgit);
+}
+
+static void repair_noop(int iserr, const char *path, const char *msg,
+			void *cb_data)
+{
+	/* nothing */
+}
+
+void repair_worktrees(worktree_repair_fn fn, void *cb_data)
+{
+	struct worktree **worktrees = get_worktrees();
+	struct worktree **wt = worktrees + 1; /* +1 skips main worktree */
+
+	if (!fn)
+		fn = repair_noop;
+	for (; *wt; wt++)
+		repair_gitfile(*wt, fn, cb_data);
+	free_worktrees(worktrees);
+}
+
+static int is_main_worktree_path(const char *path)
+{
+	struct strbuf target = STRBUF_INIT;
+	struct strbuf maindir = STRBUF_INIT;
+	int cmp;
+
+	strbuf_add_real_path(&target, path);
+	strbuf_strip_suffix(&target, "/.git");
+	strbuf_add_real_path(&maindir, get_git_common_dir());
+	strbuf_strip_suffix(&maindir, "/.git");
+	cmp = fspathcmp(maindir.buf, target.buf);
+
+	strbuf_release(&maindir);
+	strbuf_release(&target);
+	return !cmp;
+}
+
+/*
+ * Repair <repo>/worktrees/<id>/gitdir if missing, corrupt, or not pointing at
+ * the worktree's path.
+ */
+void repair_worktree_at_path(const char *path,
+			     worktree_repair_fn fn, void *cb_data)
+{
+	struct strbuf dotgit = STRBUF_INIT;
+	struct strbuf realdotgit = STRBUF_INIT;
+	struct strbuf gitdir = STRBUF_INIT;
+	struct strbuf olddotgit = STRBUF_INIT;
+	char *backlink = NULL;
+	const char *repair = NULL;
+	int err;
+
+	if (!fn)
+		fn = repair_noop;
+
+	if (is_main_worktree_path(path))
+		goto done;
+
+	strbuf_addf(&dotgit, "%s/.git", path);
+	if (!strbuf_realpath(&realdotgit, dotgit.buf, 0)) {
+		fn(1, path, _("not a valid path"), cb_data);
+		goto done;
+	}
+
+	backlink = xstrdup_or_null(read_gitfile_gently(realdotgit.buf, &err));
+	if (err == READ_GITFILE_ERR_NOT_A_FILE) {
+		fn(1, realdotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
+		goto done;
+	} else if (err) {
+		fn(1, realdotgit.buf, _("unable to locate repository; .git file broken"), cb_data);
+		goto done;
+	}
+
+	strbuf_addf(&gitdir, "%s/gitdir", backlink);
+	if (strbuf_read_file(&olddotgit, gitdir.buf, 0) < 0)
+		repair = _("gitdir unreadable");
+	else {
+		strbuf_rtrim(&olddotgit);
+		if (fspathcmp(olddotgit.buf, realdotgit.buf))
+			repair = _("gitdir incorrect");
+	}
+
+	if (repair) {
+		fn(0, gitdir.buf, repair, cb_data);
+		write_file(gitdir.buf, "%s", realdotgit.buf);
+	}
+done:
+	free(backlink);
+	strbuf_release(&olddotgit);
+	strbuf_release(&gitdir);
+	strbuf_release(&realdotgit);
+	strbuf_release(&dotgit);
+}