[PATCH v2 1/3] branch: fix die_if_checked_out() when ignore_current_worktree

["Rubén Justo" <rjusto@gmail.com>]

In 8d9fdd7 (worktree.c: check whether branch is rebased in another
worktree, 2016-04-22) die_if_checked_out() learned a new
option ignore_current_worktree, to modify the operation from "die() if
the branch is checked out in any worktree" to "die() if the branch
is checked out in any worktree other than the current one".

Unfortunately we implemented it by checking the flag is_current in the
worktree that find_shared_symref() returns.

When the same branch is checked out in several worktrees simultaneously,
find_shared_symref() will return the first matching worktree in the list
composed by get_worktrees().  If one of the worktrees with the checked
out branch is the current worktree, find_shared_symref() may or may not
return it, depending on the order of the list.

Let's stop using find_shared_symref() in die_if_checked_out(), to handle
correctly ignore_current_worktree.

Signed-off-by: Rubén Justo <rjusto@gmail.com>
---
 branch.c   | 16 +++++++++++-----
 worktree.c | 54 +++++++++++++++++++++++++++++-------------------------
 worktree.h |  6 ++++++
 3 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/branch.c b/branch.c
index d182756827..2378368415 100644
--- a/branch.c
+++ b/branch.c
@@ -820,12 +820,18 @@ void remove_branch_state(struct repository *r, int verbose)
 void die_if_checked_out(const char *branch, int ignore_current_worktree)
 {
 	struct worktree **worktrees = get_worktrees();
-	const struct worktree *wt;
+	int i;
+
+	for (i = 0; worktrees[i]; i++)
+	{
+		if (worktrees[i]->is_current && ignore_current_worktree)
+			continue;
 
-	wt = find_shared_symref(worktrees, "HEAD", branch);
-	if (wt && (!ignore_current_worktree || !wt->is_current)) {
-		skip_prefix(branch, "refs/heads/", &branch);
-		die(_("'%s' is already checked out at '%s'"), branch, wt->path);
+		if (is_shared_symref(worktrees[i], "HEAD", branch)) {
+			skip_prefix(branch, "refs/heads/", &branch);
+			die(_("'%s' is already checked out at '%s'"),
+				branch, worktrees[i]->path);
+		}
 	}
 
 	free_worktrees(worktrees);
diff --git a/worktree.c b/worktree.c
index aa43c64119..d500d69e4c 100644
--- a/worktree.c
+++ b/worktree.c
@@ -403,6 +403,33 @@ int is_worktree_being_bisected(const struct worktree *wt,
  * bisect). New commands that do similar things should update this
  * function as well.
  */
+int is_shared_symref(const struct worktree *wt, const char *symref,
+		     const char *target)
+{
+	const char *symref_target;
+	struct ref_store *refs;
+	int flags;
+
+	if (wt->is_bare)
+		return 0;
+
+	if (wt->is_detached && !strcmp(symref, "HEAD")) {
+		if (is_worktree_being_rebased(wt, target))
+			return 1;
+		if (is_worktree_being_bisected(wt, target))
+			return 1;
+	}
+
+	refs = get_worktree_ref_store(wt);
+	symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
+						NULL, &flags);
+	if ((flags & REF_ISSYMREF) &&
+	    symref_target && !strcmp(symref_target, target))
+		return 1;
+
+	return 0;
+}
+
 const struct worktree *find_shared_symref(struct worktree **worktrees,
 					  const char *symref,
 					  const char *target)
@@ -411,31 +438,8 @@ const struct worktree *find_shared_symref(struct worktree **worktrees,
 	int i = 0;
 
 	for (i = 0; worktrees[i]; i++) {
-		struct worktree *wt = worktrees[i];
-		const char *symref_target;
-		struct ref_store *refs;
-		int flags;
-
-		if (wt->is_bare)
-			continue;
-
-		if (wt->is_detached && !strcmp(symref, "HEAD")) {
-			if (is_worktree_being_rebased(wt, target)) {
-				existing = wt;
-				break;
-			}
-			if (is_worktree_being_bisected(wt, target)) {
-				existing = wt;
-				break;
-			}
-		}
-
-		refs = get_worktree_ref_store(wt);
-		symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
-							NULL, &flags);
-		if ((flags & REF_ISSYMREF) &&
-		    symref_target && !strcmp(symref_target, target)) {
-			existing = wt;
+		if (is_shared_symref(worktrees[i], symref, target)) {
+			existing = worktrees[i];
 			break;
 		}
 	}
diff --git a/worktree.h b/worktree.h
index 9dcea6fc8c..7889c4761d 100644
--- a/worktree.h
+++ b/worktree.h
@@ -149,6 +149,12 @@ const struct worktree *find_shared_symref(struct worktree **worktrees,
 					  const char *symref,
 					  const char *target);
 
+/*
+ * Returns true if a symref points to a ref in a worktree.
+ */
+int is_shared_symref(const struct worktree *wt,
+		     const char *symref, const char *target);
+
 /*
  * Similar to head_ref() for all HEADs _except_ one from the current
  * worktree, which is covered by head_ref().
-- 
2.39.0