Merge branch 'mh/fetch-tags-in-addition-to-normal-refs'

The "--tags" option to "git fetch" used to be literally a synonym to
a "refs/tags/*:refs/tags/*" refspec, which meant that (1) as an
explicit refspec given from the command line, it silenced the lazy
"git fetch" default that is configured, and (2) also as an explicit
refspec given from the command line, it interacted with "--prune"
to remove any tag that the remote we are fetching from does not
have.

This demotes it to an option; with it, we fetch all tags in
addition to what would be fetched without the option, and it does
not interact with the decision "--prune" makes to see what
remote-tracking refs the local has are missing the remote
counterpart.

* mh/fetch-tags-in-addition-to-normal-refs: (23 commits)
  fetch: improve the error messages emitted for conflicting refspecs
  handle_duplicate(): mark error message for translation
  ref_remote_duplicates(): extract a function handle_duplicate()
  ref_remove_duplicates(): simplify loop logic
  t5536: new test of refspec conflicts when fetching
  ref_remove_duplicates(): avoid redundant bisection
  git-fetch.txt: improve description of tag auto-following
  fetch-options.txt: simplify ifdef/ifndef/endif usage
  fetch, remote: properly convey --no-prune options to subprocesses
  builtin/remote.c:update(): use struct argv_array
  builtin/remote.c: reorder function definitions
  query_refspecs(): move some constants out of the loop
  fetch --prune: prune only based on explicit refspecs
  fetch --tags: fetch tags *in addition to* other stuff
  fetch: only opportunistically update references based on command line
  get_expanded_map(): avoid memory leak
  get_expanded_map(): add docstring
  builtin/fetch.c: reorder function definitions
  get_ref_map(): rename local variables
  api-remote.txt: correct section "struct refspec"
  ...

1 files changed, 66 insertions, 28 deletions

diff --git a/remote.c b/remote.c
index 9f1a8aa2c..15e6e5efc 100644
--- a/remote.c
+++ b/remote.c
@@ -745,35 +745,66 @@ int for_each_remote(each_remote_fn fn, void *priv)
 	return result;
 }
 
-void ref_remove_duplicates(struct ref *ref_map)
+static void handle_duplicate(struct ref *ref1, struct ref *ref2)
+{
+	if (strcmp(ref1->name, ref2->name)) {
+		if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+		    ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
+			die(_("Cannot fetch both %s and %s to %s"),
+			    ref1->name, ref2->name, ref2->peer_ref->name);
+		} else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+			   ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+			warning(_("%s usually tracks %s, not %s"),
+				ref2->peer_ref->name, ref2->name, ref1->name);
+		} else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
+			   ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+			die(_("%s tracks both %s and %s"),
+			    ref2->peer_ref->name, ref1->name, ref2->name);
+		} else {
+			/*
+			 * This last possibility doesn't occur because
+			 * FETCH_HEAD_IGNORE entries always appear at
+			 * the end of the list.
+			 */
+			die(_("Internal error"));
+		}
+	}
+	free(ref2->peer_ref);
+	free(ref2);
+}
+
+struct ref *ref_remove_duplicates(struct ref *ref_map)
 {
 	struct string_list refs = STRING_LIST_INIT_NODUP;
-	struct string_list_item *item = NULL;
-	struct ref *prev = NULL, *next = NULL;
-	for (; ref_map; prev = ref_map, ref_map = next) {
-		next = ref_map->next;
-		if (!ref_map->peer_ref)
-			continue;
+	struct ref *retval = NULL;
+	struct ref **p = &retval;
 
-		item = string_list_lookup(&refs, ref_map->peer_ref->name);
-		if (item) {
-			if (strcmp(((struct ref *)item->util)->name,
-				   ref_map->name))
-				die("%s tracks both %s and %s",
-				    ref_map->peer_ref->name,
-				    ((struct ref *)item->util)->name,
-				    ref_map->name);
-			prev->next = ref_map->next;
-			free(ref_map->peer_ref);
-			free(ref_map);
-			ref_map = prev; /* skip this; we freed it */
-			continue;
-		}
+	while (ref_map) {
+		struct ref *ref = ref_map;
+
+		ref_map = ref_map->next;
+		ref->next = NULL;
 
-		item = string_list_insert(&refs, ref_map->peer_ref->name);
-		item->util = ref_map;
+		if (!ref->peer_ref) {
+			*p = ref;
+			p = &ref->next;
+		} else {
+			struct string_list_item *item =
+				string_list_insert(&refs, ref->peer_ref->name);
+
+			if (item->util) {
+				/* Entry already existed */
+				handle_duplicate((struct ref *)item->util, ref);
+			} else {
+				*p = ref;
+				p = &ref->next;
+				item->util = ref;
+			}
+		}
 	}
+
 	string_list_clear(&refs, 0);
+	return retval;
 }
 
 int remote_has_url(struct remote *remote, const char *url)
@@ -825,6 +856,8 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
 {
 	int i;
 	int find_src = !query->src;
+	const char *needle = find_src ? query->dst : query->src;
+	char **result = find_src ? &query->src : &query->dst;
 
 	if (find_src && !query->dst)
 		return error("query_refspecs: need either src or dst");
@@ -833,8 +866,6 @@ static int query_refspecs(struct refspec *refs, int ref_count, struct refspec *q
 		struct refspec *refspec = &refs[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
 		const char *value = find_src ? refspec->src : refspec->dst;
-		const char *needle = find_src ? query->dst : query->src;
-		char **result = find_src ? &query->src : &query->dst;
 
 		if (!refspec->dst)
 			continue;
@@ -1553,6 +1584,13 @@ static int ignore_symref_update(const char *refname)
 	return (flag & REF_ISSYMREF);
 }
 
+/*
+ * Create and return a list of (struct ref) consisting of copies of
+ * each remote_ref that matches refspec.  refspec must be a pattern.
+ * Fill in the copies' peer_ref to describe the local tracking refs to
+ * which they map.  Omit any references that would map to an existing
+ * local symbolic ref.
+ */
 static struct ref *get_expanded_map(const struct ref *remote_refs,
 				    const struct refspec *refspec)
 {
@@ -1560,9 +1598,9 @@ static struct ref *get_expanded_map(const struct ref *remote_refs,
 	struct ref *ret = NULL;
 	struct ref **tail = &ret;
 
-	char *expn_name;
-
 	for (ref = remote_refs; ref; ref = ref->next) {
+		char *expn_name = NULL;
+
 		if (strchr(ref->name, '^'))
 			continue; /* a dereference item */
 		if (match_name_with_pattern(refspec->src, ref->name,
@@ -1571,12 +1609,12 @@ static struct ref *get_expanded_map(const struct ref *remote_refs,
 			struct ref *cpy = copy_ref(ref);
 
 			cpy->peer_ref = alloc_ref(expn_name);
-			free(expn_name);
 			if (refspec->force)
 				cpy->peer_ref->force = 1;
 			*tail = cpy;
 			tail = &cpy->next;
 		}
+		free(expn_name);
 	}
 
 	return ret;