[PATCH v3 24/30] packed_refs_lock(): report errors via a `struct strbuf *err`

[Michael Haggerty]

That way the callers don't have to come up with error messages
themselves.

Signed-off-by: Michael Haggerty <mhag...@alum.mit.edu>
---
 refs/files-backend.c  |  6 ++----
 refs/packed-backend.c | 17 +++++++++++------
 refs/packed-backend.h |  6 +++---
 3 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 88de907148..8ea4e9ab05 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1096,7 +1096,7 @@ static int files_pack_refs(struct ref_store *ref_store, 
unsigned int flags)
        struct ref_to_prune *refs_to_prune = NULL;
        struct strbuf err = STRBUF_INIT;
 
-       packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR);
+       packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
        iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
        while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
@@ -2679,9 +2679,7 @@ static int files_initial_transaction_commit(struct 
ref_store *ref_store,
                }
        }
 
-       if (packed_refs_lock(refs->packed_ref_store, 0)) {
-               strbuf_addf(err, "unable to lock packed-refs file: %s",
-                           strerror(errno));
+       if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
                ret = TRANSACTION_GENERIC_ERROR;
                goto cleanup;
        }
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index cd214e07a1..78e877a9e3 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -515,7 +515,7 @@ static int write_packed_entry(FILE *fh, const char *refname,
        return 0;
 }
 
-int packed_refs_lock(struct ref_store *ref_store, int flags)
+int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf 
*err)
 {
        struct packed_ref_store *refs =
                packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
@@ -537,9 +537,15 @@ int packed_refs_lock(struct ref_store *ref_store, int 
flags)
        if (hold_lock_file_for_update_timeout(
                            &refs->lock,
                            refs->path,
-                           flags, timeout_value) < 0 ||
-           close_lock_file(&refs->lock))
+                           flags, timeout_value) < 0) {
+               unable_to_lock_message(refs->path, errno, err);
+               return -1;
+       }
+
+       if (close_lock_file(&refs->lock)) {
+               strbuf_addf(err, "unable to close %s: %s", refs->path, 
strerror(errno));
                return -1;
+       }
 
        /*
         * Now that we hold the `packed-refs` lock, make sure that our
@@ -698,10 +704,9 @@ int repack_without_refs(struct ref_store *ref_store,
        if (!needs_repacking)
                return 0; /* no refname exists in packed refs */
 
-       if (packed_refs_lock(&refs->base, 0)) {
-               unable_to_lock_message(refs->path, errno, err);
+       if (packed_refs_lock(&refs->base, 0, err))
                return -1;
-       }
+
        packed = get_packed_refs(refs);
 
        /* Remove refnames from the cache */
diff --git a/refs/packed-backend.h b/refs/packed-backend.h
index dbc00d3396..210e3f35ce 100644
--- a/refs/packed-backend.h
+++ b/refs/packed-backend.h
@@ -6,10 +6,10 @@ struct ref_store *packed_ref_store_create(const char *path,
 
 /*
  * Lock the packed-refs file for writing. Flags is passed to
- * hold_lock_file_for_update(). Return 0 on success. On errors, set
- * errno appropriately and return a nonzero value.
+ * hold_lock_file_for_update(). Return 0 on success. On errors, write
+ * an error message to `err` and return a nonzero value.
  */
-int packed_refs_lock(struct ref_store *ref_store, int flags);
+int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf 
*err);
 
 void add_packed_ref(struct ref_store *ref_store,
                    const char *refname, const struct object_id *oid);
-- 
2.11.0