ref: support multiple worktrees check for refs

We have already set up the infrastructure to check the consistency for
refs, but we do not support multiple worktrees. However, "git-fsck(1)"
will check the refs of worktrees. As we decide to get feature parity
with "git-fsck(1)", we need to set up support for multiple worktrees.

Because each worktree has its own specific refs, instead of just showing
the users "refs/worktree/foo", we need to display the full name such as
"worktrees/<id>/refs/worktree/foo". So we should know the id of the
worktree to get the full name. Add a new parameter "struct worktree *"
for "refs-internal.h::fsck_fn". Then change the related functions to
follow this new interface.

The "packed-refs" only exists in the main worktree, so we should only
check "packed-refs" in the main worktree. Use "is_main_worktree" method
to skip checking "packed-refs" in "packed_fsck" function.

Then, enhance the "files-backend.c::files_fsck_refs_dir" function to add
"worktree/<id>/" prefix when we are not in the main worktree.

Last, add a new test to check the refname when there are multiple
worktrees to exercise the code.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

5 files changed, 26 insertions, 10 deletions

diff --git a/refs/debug.c b/refs/debug.c
index 45e2e784a0..72e80ddd6d 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -420,10 +420,11 @@ static int debug_reflog_expire(struct ref_store *ref_store, const char *refname,
 }
 
 static int debug_fsck(struct ref_store *ref_store,
-		      struct fsck_options *o)
+		      struct fsck_options *o,
+		      struct worktree *wt)
 {
 	struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
-	int res = drefs->refs->be->fsck(drefs->refs, o);
+	int res = drefs->refs->be->fsck(drefs->refs, o, wt);
 	trace_printf_key(&trace_refs, "fsck: %d\n", res);
 	return res;
 }
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 8edb700568..8bfdce64bc 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -23,6 +23,7 @@
 #include "../dir.h"
 #include "../chdir-notify.h"
 #include "../setup.h"
+#include "../worktree.h"
 #include "../wrapper.h"
 #include "../write-or-die.h"
 #include "../revision.h"
@@ -3539,6 +3540,7 @@ cleanup:
 static int files_fsck_refs_dir(struct ref_store *ref_store,
 			       struct fsck_options *o,
 			       const char *refs_check_dir,
+			       struct worktree *wt,
 			       files_fsck_refs_fn *fsck_refs_fn)
 {
 	struct strbuf refname = STRBUF_INIT;
@@ -3561,6 +3563,9 @@ static int files_fsck_refs_dir(struct ref_store *ref_store,
 		} else if (S_ISREG(iter->st.st_mode) ||
 			   S_ISLNK(iter->st.st_mode)) {
 			strbuf_reset(&refname);
+
+			if (!is_main_worktree(wt))
+				strbuf_addf(&refname, "worktrees/%s/", wt->id);
 			strbuf_addf(&refname, "%s/%s", refs_check_dir,
 				    iter->relative_path);
 
@@ -3590,7 +3595,8 @@ out:
 }
 
 static int files_fsck_refs(struct ref_store *ref_store,
-			   struct fsck_options *o)
+			   struct fsck_options *o,
+			   struct worktree *wt)
 {
 	files_fsck_refs_fn fsck_refs_fn[]= {
 		files_fsck_refs_name,
@@ -3599,17 +3605,18 @@ static int files_fsck_refs(struct ref_store *ref_store,
 
 	if (o->verbose)
 		fprintf_ln(stderr, _("Checking references consistency"));
-	return files_fsck_refs_dir(ref_store, o,  "refs", fsck_refs_fn);
+	return files_fsck_refs_dir(ref_store, o, "refs", wt, fsck_refs_fn);
 }
 
 static int files_fsck(struct ref_store *ref_store,
-		      struct fsck_options *o)
+		      struct fsck_options *o,
+		      struct worktree *wt)
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_READ, "fsck");
 
-	return files_fsck_refs(ref_store, o) |
-	       refs->packed_ref_store->be->fsck(refs->packed_ref_store, o);
+	return files_fsck_refs(ref_store, o, wt) |
+	       refs->packed_ref_store->be->fsck(refs->packed_ref_store, o, wt);
 }
 
 struct ref_storage_be refs_be_files = {
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 07c57fd541..46dcaec654 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -13,6 +13,7 @@
 #include "../lockfile.h"
 #include "../chdir-notify.h"
 #include "../statinfo.h"
+#include "../worktree.h"
 #include "../wrapper.h"
 #include "../write-or-die.h"
 #include "../trace2.h"
@@ -1754,8 +1755,13 @@ static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_s
 }
 
 static int packed_fsck(struct ref_store *ref_store UNUSED,
-		       struct fsck_options *o UNUSED)
+		       struct fsck_options *o UNUSED,
+		       struct worktree *wt)
 {
+
+	if (!is_main_worktree(wt))
+		return 0;
+
 	return 0;
 }
 
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 2313c830d8..037d7991cd 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -653,7 +653,8 @@ typedef int read_symbolic_ref_fn(struct ref_store *ref_store, const char *refnam
 				 struct strbuf *referent);
 
 typedef int fsck_fn(struct ref_store *ref_store,
-		    struct fsck_options *o);
+		    struct fsck_options *o,
+		    struct worktree *wt);
 
 struct ref_storage_be {
 	const char *name;
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 3c6107c7ce..ea054ec6e9 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -2475,7 +2475,8 @@ done:
 }
 
 static int reftable_be_fsck(struct ref_store *ref_store UNUSED,
-			    struct fsck_options *o UNUSED)
+			    struct fsck_options *o UNUSED,
+			    struct worktree *wt UNUSED)
 {
 	return 0;
 }