[PATCH 22/24] refs.c: do not permit err == NULL

[Jonathan Nieder <jrnieder@gmail.com>]

Date: Thu, 28 Aug 2014 16:42:37 -0700

Some functions that take a strbuf argument to append an error treat
!err as an indication that the message should be suppressed (e.g.,
ref_update_reject_duplicates).  Others write the message to stderr on
!err (e.g., repack_without_refs).  Others crash (e.g.,
ref_transaction_update).

Some of these behaviors are for historical reasons and others were
accidents.  Luckily no callers pass err == NULL any more.  Simplify
by consistently requiring the strbuf argument.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Since v21:
- dropped spurious 'to' from commit message

 refs.c | 46 +++++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/refs.c b/refs.c
index 0d3abb1..e13f843 100644
--- a/refs.c
+++ b/refs.c
@@ -2596,6 +2596,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 	struct string_list_item *ref_to_delete;
 	int i, ret, removed = 0;
 
+	assert(err);
+
 	/* Look for a packed ref */
 	for (i = 0; i < n; i++)
 		if (get_packed_ref(refnames[i]))
@@ -2606,13 +2608,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(0)) {
-		if (err) {
-			unable_to_lock_message(git_path("packed-refs"), errno,
-					       err);
-			return -1;
-		}
-		unable_to_lock_error(git_path("packed-refs"), errno);
-		return error("cannot delete '%s' from packed refs", refnames[i]);
+		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		return -1;
 	}
 	packed = get_packed_refs(&ref_cache);
 
@@ -2638,7 +2635,7 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 	/* Write what remains */
 	ret = commit_packed_refs();
-	if (ret && err)
+	if (ret)
 		strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
 			    strerror(errno));
 	return ret;
@@ -2646,6 +2643,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 {
+	assert(err);
+
 	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 		/* loose */
 		int res, i = strlen(lock->lk->filename) - 5; /* .lock */
@@ -3495,6 +3494,8 @@ struct ref_transaction {
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
+	assert(err);
+
 	return xcalloc(1, sizeof(struct ref_transaction));
 }
 
@@ -3534,6 +3535,8 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: update called for transaction that is not open");
 
@@ -3566,6 +3569,8 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: create called for transaction that is not open");
 
@@ -3597,6 +3602,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: delete called for transaction that is not open");
 
@@ -3659,13 +3666,14 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 					struct strbuf *err)
 {
 	int i;
+
+	assert(err);
+
 	for (i = 1; i < n; i++)
 		if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
-			const char *str =
-				"Multiple updates for ref '%s' not allowed.";
-			if (err)
-				strbuf_addf(err, str, updates[i]->refname);
-
+			strbuf_addf(err,
+				    "Multiple updates for ref '%s' not allowed.",
+				    updates[i]->refname);
 			return 1;
 		}
 	return 0;
@@ -3679,6 +3687,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	int n = transaction->nr;
 	struct ref_update **updates = transaction->updates;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: commit called for transaction that is not open");
 
@@ -3715,9 +3725,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 			ret = (errno == ENOTDIR)
 				? TRANSACTION_NAME_CONFLICT
 				: TRANSACTION_GENERIC_ERROR;
-			if (err)
-				strbuf_addf(err, "Cannot lock the ref '%s'.",
-					    update->refname);
+			strbuf_addf(err, "Cannot lock the ref '%s'.",
+				    update->refname);
 			goto cleanup;
 		}
 	}
@@ -3730,9 +3739,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 			if (write_ref_sha1(update->lock, update->new_sha1,
 					   update->msg)) {
 				update->lock = NULL; /* freed by write_ref_sha1 */
-				if (err)
-					strbuf_addf(err, "Cannot update the ref '%s'.",
-						    update->refname);
+				strbuf_addf(err, "Cannot update the ref '%s'.",
+					    update->refname);
 				ret = TRANSACTION_GENERIC_ERROR;
 				goto cleanup;
 			}
-- 
2.1.0.rc2.206.gedb03e5