The ref_transaction_update() family of functions use the following
convention for their old_sha1 parameters:
* old_sha1 == NULL: Don't check the old value at all.
* is_null_sha1(old_sha1): Ensure that the reference didn't exist
before the transaction.
* otherwise: Ensure that the reference had the specified value before
the transaction.
delete_ref() had a different convention, namely treating
is_null_sha1(old_sha1) as "don't care". Change it to adhere to the
standard convention to reduce the scope for confusion.
Please note that it is now a bug to pass old_sha1=NULL_SHA1 to
delete_ref() (because it doesn't make sense to delete a reference that
you already know doesn't exist). This is consistent with the behavior
of ref_transaction_delete().
Most of the callers of delete_ref() never pass old_sha1=NULL_SHA1 to
delete_ref(), and are therefore unaffected by this change. The
two exceptions are:
* The call in cmd_update_ref(), which passed NULL_SHA1 if the old
value passed in on the command line was 0{40} or the empty string.
Change that caller to pass NULL in those cases.
Arguably, it should be an error to call "update-ref -d" with the old
value set to "does not exist", just as it is for the `--stdin`
command "delete". But since this usage was accepted until now,
continue to accept it.
* The call in delete_branches(), which could pass NULL_SHA1 if
deleting a broken or symbolic ref. Change it to pass NULL in these
cases.
Signed-off-by: Michael Haggerty <mhagger@xxxxxxxxxxxx>
---
builtin/branch.c | 3 ++-
builtin/update-ref.c | 8 +++++++-
refs.c | 8 --------
refs.h | 10 +++++-----
4 files changed, 14 insertions(+), 15 deletions(-)
diff --git a/builtin/branch.c b/builtin/branch.c
index 47e3eb9..58aa84f 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -253,7 +253,8 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
continue;
}
- if (delete_ref(name, sha1, REF_NODEREF)) {
+ if (delete_ref(name, is_null_sha1(sha1) ? NULL : sha1,
+ REF_NODEREF)) {
error(remote_branch
? _("Error deleting remote-tracking branch '%s'")
: _("Error deleting branch '%s'"),
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 160c7ac..6763cf1 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -422,7 +422,13 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
if (no_deref)
flags = REF_NODEREF;
if (delete)
- return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
+ /*
+ * For purposes of backwards compatibility, we treat
+ * NULL_SHA1 as "don't care" here:
+ */
+ return delete_ref(refname,
+ (oldval && !is_null_sha1(oldsha1)) ? oldsha1 : NULL,
+ flags);
else
return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
flags, UPDATE_REFS_DIE_ON_ERR);
diff --git a/refs.c b/refs.c
index 2ba618e..adf3dc2 100644
--- a/refs.c
+++ b/refs.c
@@ -2821,14 +2821,6 @@ int delete_ref(const char *refname, const unsigned char *old_sha1,
struct ref_transaction *transaction;
struct strbuf err = STRBUF_INIT;
- /*
- * Treat NULL_SHA1 and NULL alike, to mean "we don't care what
- * the old value of the reference was (or even if it didn't
- * exist)":
- */
- if (old_sha1 && is_null_sha1(old_sha1))
- old_sha1 = NULL;
-
transaction = ref_transaction_begin(&err);
if (!transaction ||
ref_transaction_delete(transaction, refname, old_sha1,
diff --git a/refs.h b/refs.h
index c9596ea..e82fca5 100644
--- a/refs.h
+++ b/refs.h
@@ -240,11 +240,11 @@ extern int read_ref_at(const char *refname, unsigned int flags,
extern int reflog_exists(const char *refname);
/*
- * Delete the specified reference. If old_sha1 is non-NULL and not
- * NULL_SHA1, then verify that the current value of the reference is
- * old_sha1 before deleting it. If old_sha1 is NULL or NULL_SHA1,
- * delete the reference if it exists, regardless of its old value.
- * flags is passed through to ref_transaction_delete().
+ * Delete the specified reference. If old_sha1 is non-NULL, then
+ * verify that the current value of the reference is old_sha1 before
+ * deleting it. If old_sha1 is NULL, delete the reference if it
+ * exists, regardless of its old value. It is an error for old_sha1 to
+ * be NULL_SHA1. flags is passed through to ref_transaction_delete().
*/
extern int delete_ref(const char *refname, const unsigned char *old_sha1,
unsigned int flags);
--
2.1.4
--
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