[PATCH v2 10/23] fetch --tags: fetch tags *in addition to* other stuff

[Michael Haggerty <mhagger@alum.mit.edu>]

Previously, fetch's "--tags" option was considered equivalent to
specifying the refspec "refs/tags/*:refs/tags/*" on the command line;
in particular, it caused the remote.<name>.refspec configuration to be
ignored.

But it is not very useful to fetch tags without also fetching other
references, whereas it *is* quite useful to be able to fetch tags *in
addition to* other references.  So change the semantics of this option
to do the latter.

If a user wants to fetch *only* tags, then it is still possible to
specifying an explicit refspec:

    git fetch <remote> 'refs/tags/*:refs/tags/*'

Please note that the documentation prior to 1.8.0.3 was ambiguous
about this aspect of "fetch --tags" behavior.  Commit

    f0cb2f137c 2012-12-14 fetch --tags: clarify documentation

made the documentation match the old behavior.  This commit changes
the documentation to match the new behavior.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 Documentation/fetch-options.txt          |  8 ++---
 builtin/fetch.c                          | 59 +++++++++++++++++++-------------
 git-pull.sh                              |  2 +-
 t/t5510-fetch.sh                         | 22 ++++++++++--
 t/t5515/fetch.br-unconfig_--tags_.._.git |  1 +
 t/t5515/fetch.master_--tags_.._.git      |  1 +
 t/t5525-fetch-tagopt.sh                  | 23 ++++++++++---
 7 files changed, 78 insertions(+), 38 deletions(-)

diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index ba1fe49..921f6be 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -61,11 +61,9 @@ endif::git-pull[]
 ifndef::git-pull[]
 -t::
 --tags::
-	This is a short-hand for giving `refs/tags/*:refs/tags/*`
-	refspec from the command line, to ask all tags to be fetched
-	and stored locally.  Because this acts as an explicit
-	refspec, the default refspecs (configured with the
-	remote.$name.fetch variable) are overridden and not used.
+	Request that all tags be fetched from the remote in addition
+	to whatever else is being fetched.  Its effect is similar to
+	that of the refspec `refs/tags/*:refs/tags/*`.
 
 --recurse-submodules[=yes|on-demand|no]::
 	This option controls if and under what conditions new commits of
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 0849f09..887fa3e 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -269,12 +269,12 @@ static struct ref *get_ref_map(struct transport *transport,
 	struct ref *ref_map = NULL;
 	struct ref **tail = &ref_map;
 
-	const struct ref *remote_refs = transport_get_remote_refs(transport);
+	/* opportunistically-updated references: */
+	struct ref *orefs = NULL, **oref_tail = &orefs;
 
-	if (refspec_count || tags == TAGS_SET) {
-		/* opportunistically-updated references: */
-		struct ref *orefs = NULL, **oref_tail = &orefs;
+	const struct ref *remote_refs = transport_get_remote_refs(transport);
 
+	if (refspec_count) {
 		for (i = 0; i < refspec_count; i++) {
 			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
 			if (refspecs[i].dst && refspecs[i].dst[0])
@@ -310,12 +310,6 @@ static struct ref *get_ref_map(struct transport *transport,
 
 		if (tags == TAGS_SET)
 			get_fetch_map(remote_refs, tag_refspec, &tail, 0);
-
-		*tail = orefs;
-		for (rm = orefs; rm; rm = rm->next) {
-			rm->fetch_head_status = FETCH_HEAD_IGNORE;
-			tail = &rm->next;
-		}
 	} else {
 		/* Use the defaults */
 		struct remote *remote = transport->remote;
@@ -353,9 +347,19 @@ static struct ref *get_ref_map(struct transport *transport,
 		}
 	}
 
-	if (tags == TAGS_DEFAULT && *autotags)
+	if (tags == TAGS_SET)
+		/* also fetch all tags */
+		get_fetch_map(remote_refs, tag_refspec, &tail, 0);
+	else if (tags == TAGS_DEFAULT && *autotags)
 		find_non_local_tags(transport, &ref_map, &tail);
 
+	/* Now append any refs to be updated opportunistically: */
+	*tail = orefs;
+	for (rm = orefs; rm; rm = rm->next) {
+		rm->fetch_head_status = FETCH_HEAD_IGNORE;
+		tail = &rm->next;
+	}
+
 	ref_remove_duplicates(ref_map);
 
 	return ref_map;
@@ -846,31 +850,38 @@ static int do_fetch(struct transport *transport,
 		goto cleanup;
 	}
 	if (prune) {
-		/*
-		 * If --tags was specified, pretend that the user gave us
-		 * the canonical tags refspec
-		 */
+		struct refspec *prune_refspecs;
+		int prune_refspec_count;
+
+		if (ref_count) {
+			prune_refspecs = refs;
+			prune_refspec_count = ref_count;
+		} else {
+			prune_refspecs = transport->remote->fetch;
+			prune_refspec_count = transport->remote->fetch_refspec_nr;
+		}
+
 		if (tags == TAGS_SET) {
+			/*
+			 * --tags was specified.  Pretend that the user also
+			 * gave us the canonical tags refspec
+			 */
 			const char *tags_str = "refs/tags/*:refs/tags/*";
 			struct refspec *tags_refspec, *refspec;
 
 			/* Copy the refspec and add the tags to it */
-			refspec = xcalloc(ref_count + 1, sizeof(struct refspec));
+			refspec = xcalloc(prune_refspec_count + 1, sizeof(*refspec));
 			tags_refspec = parse_fetch_refspec(1, &tags_str);
-			memcpy(refspec, refs, ref_count * sizeof(struct refspec));
-			memcpy(&refspec[ref_count], tags_refspec, sizeof(struct refspec));
-			ref_count++;
+			memcpy(refspec, prune_refspecs, prune_refspec_count * sizeof(*refspec));
+			memcpy(&refspec[prune_refspec_count], tags_refspec, sizeof(*refspec));
 
-			prune_refs(refspec, ref_count, ref_map);
+			prune_refs(refspec, prune_refspec_count + 1, ref_map);
 
-			ref_count--;
 			/* The rest of the strings belong to fetch_one */
 			free_refspec(1, tags_refspec);
 			free(refspec);
-		} else if (ref_count) {
-			prune_refs(refs, ref_count, ref_map);
 		} else {
-			prune_refs(transport->remote->fetch, transport->remote->fetch_refspec_nr, ref_map);
+			prune_refs(prune_refspecs, prune_refspec_count, ref_map);
 		}
 	}
 	free_refs(ref_map);
diff --git a/git-pull.sh b/git-pull.sh
index b946fd9..97716b8 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -172,7 +172,7 @@ error_on_no_merge_candidates () {
 	do
 		case "$opt" in
 		-t|--t|--ta|--tag|--tags)
-			echo "Fetching tags only, you probably meant:"
+			echo "It doesn't make sense to pull all tags; you probably meant:"
 			echo "  git fetch --tags"
 			exit 1
 		esac
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 8328be1..02e5901 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -113,7 +113,7 @@ test_expect_success 'fetch --prune with a namespace keeps other namespaces' '
 	git rev-parse origin/master
 '
 
-test_expect_success 'fetch --prune --tags does not delete the remote-tracking branches' '
+test_expect_success 'fetch --prune --tags prunes tags and branches' '
 	cd "$D" &&
 	git clone . prune-tags &&
 	cd prune-tags &&
@@ -124,7 +124,7 @@ test_expect_success 'fetch --prune --tags does not delete the remote-tracking br
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
-	git rev-parse origin/fake-remote &&
+	test_must_fail git rev-parse origin/fake-remote &&
 	test_must_fail git rev-parse sometag
 '
 
@@ -132,10 +132,26 @@ test_expect_success 'fetch --prune --tags with branch does not delete other remo
 	cd "$D" &&
 	git clone . prune-tags-branch &&
 	cd prune-tags-branch &&
+	git tag sometag master &&
 	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune --tags origin master &&
-	git rev-parse origin/extrabranch
+	git rev-parse origin/extrabranch &&
+	test_must_fail git rev-parse sometag
+'
+
+test_expect_success 'fetch --prune --tags with refspec prunes based on refspec' '
+	cd "$D" &&
+	git clone . prune-tags-refspec &&
+	cd prune-tags-refspec &&
+	git tag sometag master &&
+	git update-ref refs/remotes/origin/foo/otherbranch master &&
+	git update-ref refs/remotes/origin/extrabranch master &&
+
+	git fetch --prune --tags origin refs/heads/foo/*:refs/remotes/origin/foo/* &&
+	test_must_fail git rev-parse refs/remotes/origin/foo/otherbranch &&
+	git rev-parse origin/extrabranch &&
+	test_must_fail git rev-parse sometag
 '
 
 test_expect_success 'fetch tags when there is no tags' '
diff --git a/t/t5515/fetch.br-unconfig_--tags_.._.git b/t/t5515/fetch.br-unconfig_--tags_.._.git
index 1669cc4..0f70f66 100644
--- a/t/t5515/fetch.br-unconfig_--tags_.._.git
+++ b/t/t5515/fetch.br-unconfig_--tags_.._.git
@@ -1,4 +1,5 @@
 # br-unconfig --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5515/fetch.master_--tags_.._.git b/t/t5515/fetch.master_--tags_.._.git
index 8a74935..ab473a6 100644
--- a/t/t5515/fetch.master_--tags_.._.git
+++ b/t/t5515/fetch.master_--tags_.._.git
@@ -1,4 +1,5 @@
 # master --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5525-fetch-tagopt.sh b/t/t5525-fetch-tagopt.sh
index 4fbf7a1..45815f7 100755
--- a/t/t5525-fetch-tagopt.sh
+++ b/t/t5525-fetch-tagopt.sh
@@ -8,7 +8,8 @@ setup_clone () {
 	git clone --mirror . $1 &&
 	git remote add remote_$1 $1 &&
 	(cd $1 &&
-	git tag tag_$1)
+	git tag tag_$1 &&
+	git branch branch_$1)
 }
 
 test_expect_success setup '
@@ -21,21 +22,33 @@ test_expect_success setup '
 
 test_expect_success "fetch with tagopt=--no-tags does not get tag" '
 	git fetch remote_one &&
-	test_must_fail git show-ref tag_one
+	test_must_fail git show-ref tag_one &&
+	git show-ref remote_one/branch_one
 	'
 
 test_expect_success "fetch --tags with tagopt=--no-tags gets tag" '
+	(
+		cd one &&
+		git branch second_branch_one
+	) &&
 	git fetch --tags remote_one &&
-	git show-ref tag_one
+	git show-ref tag_one &&
+	git show-ref remote_one/second_branch_one
 	'
 
 test_expect_success "fetch --no-tags with tagopt=--tags does not get tag" '
 	git fetch --no-tags remote_two &&
-	test_must_fail git show-ref tag_two
+	test_must_fail git show-ref tag_two &&
+	git show-ref remote_two/branch_two
 	'
 
 test_expect_success "fetch with tagopt=--tags gets tag" '
+	(
+		cd two &&
+		git branch second_branch_two
+	) &&
 	git fetch remote_two &&
-	git show-ref tag_two
+	git show-ref tag_two &&
+	git show-ref remote_two/second_branch_two
 	'
 test_done
-- 
1.8.4.1