Merge branch 'ph/fetch-prune-optim'

"git fetch --prune" used to be O(n^2) expensive when there are many
refs, which has been corrected.

* ph/fetch-prune-optim:
  clean up interface for refs_warn_dangling_symrefs
  refs: remove old refs_warn_dangling_symref
  fetch-prune: optimize dangling-ref reporting

Author: gitster

builtin/fetch.c

@@ -1340,9 +1340,10 @@ static int prune_refs(struct display_state *display_state,
 	int result = 0;
 	struct ref *ref, *stale_refs = get_stale_heads(rs, ref_map);
 	struct strbuf err = STRBUF_INIT;
-	const char *dangling_msg = dry_run
-		? _("   (%s will become dangling)")
-		: _("   (%s has become dangling)");
+	struct string_list refnames = STRING_LIST_INIT_NODUP;
+
+	for (ref = stale_refs; ref; ref = ref->next)
+		string_list_append(&refnames, ref->name);
 
 	if (!dry_run) {
 		if (transaction) {
@@ -1353,15 +1354,9 @@ static int prune_refs(struct display_state *display_state,
 					goto cleanup;
 			}
 		} else {
-			struct string_list refnames = STRING_LIST_INIT_NODUP;
-
-			for (ref = stale_refs; ref; ref = ref->next)
-				string_list_append(&refnames, ref->name);
-
 			result = refs_delete_refs(get_main_ref_store(the_repository),
 						  "fetch: prune", &refnames,
 						  0);
-			string_list_clear(&refnames, 0);
 		}
 	}
 
@@ -1373,12 +1368,14 @@ static int prune_refs(struct display_state *display_state,
 					   _("(none)"), ref->name,
 					   &ref->new_oid, &ref->old_oid,
 					   summary_width);
-			refs_warn_dangling_symref(get_main_ref_store(the_repository),
-						  stderr, dangling_msg, ref->name);
 		}
+		string_list_sort(&refnames);
+		refs_warn_dangling_symrefs(get_main_ref_store(the_repository),
+					   stderr, "   ", dry_run, &refnames);
 	}
 
 cleanup:
+	string_list_clear(&refnames, 0);
 	strbuf_release(&err);
 	free_refs(stale_refs);
 	return result;

builtin/remote.c

@@ -1521,9 +1521,6 @@ static int prune_remote(const char *remote, int dry_run)
 	struct ref_states states = REF_STATES_INIT;
 	struct string_list refs_to_prune = STRING_LIST_INIT_NODUP;
 	struct string_list_item *item;
-	const char *dangling_msg = dry_run
-		? _(" %s will become dangling!")
-		: _(" %s has become dangling!");
 
 	get_remote_ref_states(remote, &states, GET_REF_STATES);
 
@@ -1555,7 +1552,7 @@ static int prune_remote(const char *remote, int dry_run)
 	}
 
 	refs_warn_dangling_symrefs(get_main_ref_store(the_repository),
-				   stdout, dangling_msg, &refs_to_prune);
+				   stdout, " ", dry_run, &refs_to_prune);
 
 	string_list_clear(&refs_to_prune, 0);
 	free_remote_ref_states(&states);

refs.c

@@ -439,54 +439,44 @@ static int for_each_filter_refs(const char *refname, const char *referent,
 struct warn_if_dangling_data {
 	struct ref_store *refs;
 	FILE *fp;
-	const char *refname;
 	const struct string_list *refnames;
-	const char *msg_fmt;
+	const char *indent;
+	int dry_run;
 };
 
 static int warn_if_dangling_symref(const char *refname, const char *referent UNUSED,
 				   const struct object_id *oid UNUSED,
 				   int flags, void *cb_data)
 {
 	struct warn_if_dangling_data *d = cb_data;
-	const char *resolves_to;
+	const char *resolves_to, *msg;
 
 	if (!(flags & REF_ISSYMREF))
 		return 0;
 
 	resolves_to = refs_resolve_ref_unsafe(d->refs, refname, 0, NULL, NULL);
 	if (!resolves_to
-	    || (d->refname
-		? strcmp(resolves_to, d->refname)
-		: !string_list_has_string(d->refnames, resolves_to))) {
+	    || !string_list_has_string(d->refnames, resolves_to)) {
 		return 0;
 	}
 
-	fprintf(d->fp, d->msg_fmt, refname);
-	fputc('\n', d->fp);
+	msg = d->dry_run
+		? _("%s%s will become dangling after %s is deleted\n")
+		: _("%s%s has become dangling after %s was deleted\n");
+	fprintf(d->fp, msg, d->indent, refname, resolves_to);
 	return 0;
 }
 
-void refs_warn_dangling_symref(struct ref_store *refs, FILE *fp,
-			       const char *msg_fmt, const char *refname)
-{
-	struct warn_if_dangling_data data = {
-		.refs = refs,
-		.fp = fp,
-		.refname = refname,
-		.msg_fmt = msg_fmt,
-	};
-	refs_for_each_rawref(refs, warn_if_dangling_symref, &data);
-}
-
 void refs_warn_dangling_symrefs(struct ref_store *refs, FILE *fp,
-				const char *msg_fmt, const struct string_list *refnames)
+				const char *indent, int dry_run,
+				const struct string_list *refnames)
 {
 	struct warn_if_dangling_data data = {
 		.refs = refs,
 		.fp = fp,
 		.refnames = refnames,
-		.msg_fmt = msg_fmt,
+		.indent = indent,
+		.dry_run = dry_run,
 	};
 	refs_for_each_rawref(refs, warn_if_dangling_symref, &data);
 }

refs.h

@@ -452,10 +452,9 @@ static inline const char *has_glob_specials(const char *pattern)
 	return strpbrk(pattern, "?*[");
 }
 
-void refs_warn_dangling_symref(struct ref_store *refs, FILE *fp,
-			       const char *msg_fmt, const char *refname);
 void refs_warn_dangling_symrefs(struct ref_store *refs, FILE *fp,
-				const char *msg_fmt, const struct string_list *refnames);
+				const char *indent, int dry_run,
+				const struct string_list *refnames);
 
 /*
  * Flags for controlling behaviour of pack_refs()