Merge branch 'kn/ref-transaction-symref'

Updates to symbolic refs can now be made as a part of ref
transaction.

* kn/ref-transaction-symref:
  refs: remove `create_symref` and associated dead code
  refs: rename `refs_create_symref()` to `refs_update_symref()`
  refs: use transaction in `refs_create_symref()`
  refs: add support for transactional symref updates
  refs: move `original_update_refname` to 'refs.c'
  refs: support symrefs in 'reference-transaction' hook
  files-backend: extract out `create_symref_lock()`
  refs: accept symref values in `ref_transaction_update()`

Author: gitster

Documentation/githooks.txt

@@ -486,7 +486,7 @@ reference-transaction
 This hook is invoked by any Git command that performs reference
 updates. It executes whenever a reference transaction is prepared,
 committed or aborted and may thus get called multiple times. The hook
-does not cover symbolic references (but that may change in the future).
+also supports symbolic reference updates.
 
 The hook takes exactly one argument, which is the current state the
 given reference transaction is in:
@@ -503,16 +503,20 @@ given reference transaction is in:
 For each reference update that was added to the transaction, the hook
 receives on standard input a line of the format:
 
-  <old-oid> SP <new-oid> SP <ref-name> LF
+  <old-value> SP <new-value> SP <ref-name> LF
 
-where `<old-oid>` is the old object name passed into the reference
-transaction, `<new-oid>` is the new object name to be stored in the
+where `<old-value>` is the old object name passed into the reference
+transaction, `<new-value>` is the new object name to be stored in the
 ref and `<ref-name>` is the full name of the ref. When force updating
 the reference regardless of its current value or when the reference is
-to be created anew, `<old-oid>` is the all-zeroes object name. To
+to be created anew, `<old-value>` is the all-zeroes object name. To
 distinguish these cases, you can inspect the current value of
 `<ref-name>` via `git rev-parse`.
 
+For symbolic reference updates the `<old_value>` and `<new-value>`
+fields could denote references instead of objects. A reference will be
+denoted with a 'ref:' prefix, like `ref:<ref-target>`.
+
 The exit status of the hook is ignored for any state except for the
 "prepared" state. In the "prepared" state, a non-zero exit status will
 cause the transaction to be aborted. The hook will not be called with

branch.c

@@ -628,7 +628,7 @@ void create_branch(struct repository *r,
 	if (!transaction ||
 		ref_transaction_update(transaction, ref.buf,
 					&oid, forcing ? NULL : null_oid(),
-					0, msg, &err) ||
+					NULL, NULL, 0, msg, &err) ||
 		ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 	ref_transaction_free(transaction);

builtin/branch.c

@@ -559,7 +559,7 @@ static int replace_each_worktree_head_symref(struct worktree **worktrees,
 			continue;
 
 		refs = get_worktree_ref_store(worktrees[i]);
-		if (refs_create_symref(refs, "HEAD", newref, logmsg))
+		if (refs_update_symref(refs, "HEAD", newref, logmsg))
 			ret = error(_("HEAD of working tree %s is not updated"),
 				    worktrees[i]->path);
 	}

builtin/checkout.c

@@ -1011,7 +1011,7 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 			describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
 		}
 	} else if (new_branch_info->path) {	/* Switch branches. */
-		if (refs_create_symref(get_main_ref_store(the_repository), "HEAD", new_branch_info->path, msg.buf) < 0)
+		if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", new_branch_info->path, msg.buf) < 0)
 			die(_("unable to update HEAD"));
 		if (!opts->quiet) {
 			if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
@@ -1472,7 +1472,7 @@ static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
 	if (!opts->new_branch)
 		die(_("You are on a branch yet to be born"));
 	strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
-	status = refs_create_symref(get_main_ref_store(the_repository),
+	status = refs_update_symref(get_main_ref_store(the_repository),
 				    "HEAD", branch_ref.buf, "checkout -b");
 	strbuf_release(&branch_ref);
 	if (!opts->quiet)

builtin/clone.c

@@ -653,7 +653,7 @@ static void update_remote_refs(const struct ref *refs,
 		struct strbuf head_ref = STRBUF_INIT;
 		strbuf_addstr(&head_ref, branch_top);
 		strbuf_addstr(&head_ref, "HEAD");
-		if (refs_create_symref(get_main_ref_store(the_repository), head_ref.buf,
+		if (refs_update_symref(get_main_ref_store(the_repository), head_ref.buf,
 				       remote_head_points_at->peer_ref->name,
 				       msg) < 0)
 			die(_("unable to update %s"), head_ref.buf);
@@ -667,7 +667,7 @@ static void update_head(const struct ref *our, const struct ref *remote,
 	const char *head;
 	if (our && skip_prefix(our->name, "refs/heads/", &head)) {
 		/* Local default branch link */
-		if (refs_create_symref(get_main_ref_store(the_repository), "HEAD", our->name, NULL) < 0)
+		if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", our->name, NULL) < 0)
 			die(_("unable to update HEAD"));
 		if (!option_bare) {
 			refs_update_ref(get_main_ref_store(the_repository),
@@ -696,7 +696,7 @@ static void update_head(const struct ref *our, const struct ref *remote,
 		 * Unborn head from remote; same as "our" case above except
 		 * that we have no ref to update.
 		 */
-		if (refs_create_symref(get_main_ref_store(the_repository), "HEAD", unborn, NULL) < 0)
+		if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", unborn, NULL) < 0)
 			die(_("unable to update HEAD"));
 		if (!option_bare)
 			install_branch_config(0, head, remote_name, unborn);

builtin/fast-import.c

@@ -1636,7 +1636,7 @@ static int update_branch(struct branch *b)
 						  &err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, b->name, &b->oid, &old_oid,
-				   0, msg, &err) ||
+				   NULL, NULL, 0, msg, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);
@@ -1678,7 +1678,8 @@ static void dump_tags(void)
 		strbuf_addf(&ref_name, "refs/tags/%s", t->name);
 
 		if (ref_transaction_update(transaction, ref_name.buf,
-					   &t->oid, NULL, 0, msg, &err)) {
+					   &t->oid, NULL, NULL, NULL,
+					   0, msg, &err)) {
 			failure |= error("%s", err.buf);
 			goto cleanup;
 		}

builtin/fetch.c

@@ -672,7 +672,7 @@ static int s_update_ref(const char *action,
 
 	ret = ref_transaction_update(transaction, ref->name, &ref->new_oid,
 				     check_old ? &ref->old_oid : NULL,
-				     0, msg, &err);
+				     NULL, NULL, 0, msg, &err);
 	if (ret) {
 		ret = STORE_REF_ERROR_OTHER;
 		goto out;

builtin/notes.c

@@ -981,7 +981,7 @@ static int merge(int argc, const char **argv, const char *prefix)
 			die(_("a notes merge into %s is already in-progress at %s"),
 			    default_notes_ref(), wt->path);
 		free_worktrees(worktrees);
-		if (refs_create_symref(get_main_ref_store(the_repository), "NOTES_MERGE_REF", default_notes_ref(), NULL))
+		if (refs_update_symref(get_main_ref_store(the_repository), "NOTES_MERGE_REF", default_notes_ref(), NULL))
 			die(_("failed to store link to current notes ref (%s)"),
 			    default_notes_ref());
 		fprintf(stderr, _("Automatic notes merge failed. Fix conflicts in %s "

builtin/receive-pack.c

@@ -1595,6 +1595,7 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		if (ref_transaction_update(transaction,
 					   namespaced_name,
 					   new_oid, old_oid,
+					   NULL, NULL,
 					   0, "push",
 					   &err)) {
 			rp_error("%s", err.buf);

builtin/remote.c

@@ -240,7 +240,7 @@ static int add(int argc, const char **argv, const char *prefix)
 		strbuf_reset(&buf2);
 		strbuf_addf(&buf2, "refs/remotes/%s/%s", name, master);
 
-		if (refs_create_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, "remote add"))
+		if (refs_update_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, "remote add"))
 			return error(_("Could not setup master '%s'"), master);
 	}
 
@@ -845,7 +845,7 @@ static int mv(int argc, const char **argv, const char *prefix)
 		strbuf_reset(&buf3);
 		strbuf_addf(&buf3, "remote: renamed %s to %s",
 				item->string, buf.buf);
-		if (refs_create_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, buf3.buf))
+		if (refs_update_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, buf3.buf))
 			die(_("creating '%s' failed"), buf.buf);
 		display_progress(progress, ++refs_renamed_nr);
 	}
@@ -1423,7 +1423,7 @@ static int set_head(int argc, const char **argv, const char *prefix)
 		/* make sure it's valid */
 		if (!refs_ref_exists(get_main_ref_store(the_repository), buf2.buf))
 			result |= error(_("Not a valid ref: %s"), buf2.buf);
-		else if (refs_create_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, "remote set-head"))
+		else if (refs_update_symref(get_main_ref_store(the_repository), buf.buf, buf2.buf, "remote set-head"))
 			result |= error(_("Could not setup %s"), buf.buf);
 		else if (opt_a)
 			printf("%s/HEAD set to %s\n", argv[0], head_name);