Merge branch 'jc/maint-no-reflog-expire-unreach-for-head'

* jc/maint-no-reflog-expire-unreach-for-head:
  reflog --expire-unreachable: special case entries in "HEAD" reflog
  more war on "sleep" in tests
  Document gc.<pattern>.reflogexpire variables

Conflicts:
	Documentation/config.txt

Documentation/config.txt

@@ -946,13 +946,19 @@ gc.pruneexpire::
 	unreachable objects immediately.
 
 gc.reflogexpire::
+gc.<pattern>.reflogexpire::
 	'git reflog expire' removes reflog entries older than
-	this time; defaults to 90 days.
+	this time; defaults to 90 days.  With "<pattern>" (e.g.
+	"refs/stash") in the middle the setting applies only to
+	the refs that match the <pattern>.
 
 gc.reflogexpireunreachable::
+gc.<ref>.reflogexpireunreachable::
 	'git reflog expire' removes reflog entries older than
 	this time and are not reachable from the current tip;
-	defaults to 30 days.
+	defaults to 30 days.  With "<pattern>" (e.g. "refs/stash")
+	in the middle, the setting applies only to the refs that
+	match the <pattern>.
 
 gc.rerereresolved::
 	Records of conflicted merge you resolved earlier are

Documentation/git-gc.txt

@@ -88,6 +88,16 @@ commits prior to the amend or rebase occurring.  Since these changes
 are not part of the current project most users will want to expire
 them sooner.  This option defaults to '30 days'.
 
+The above two configuration variables can be given to a pattern.  For
+example, this sets non-default expiry values only to remote tracking
+branches:
+
+------------
+[gc "refs/remotes/*"]
+	reflogExpire = never
+	reflogexpireUnreachable = 3 days
+------------
+
 The optional configuration variable 'gc.rerereresolved' indicates
 how long records of conflicted merge you resolved earlier are
 kept.  This defaults to 60 days.

builtin/reflog.c

@@ -34,8 +34,11 @@ struct cmd_reflog_expire_cb {
 
 struct expire_reflog_cb {
 	FILE *newlog;
-	const char *ref;
-	struct commit *ref_commit;
+	enum {
+		UE_NORMAL,
+		UE_ALWAYS,
+		UE_HEAD
+	} unreachable_expire_kind;
 	struct commit_list *mark_list;
 	unsigned long mark_limit;
 	struct cmd_reflog_expire_cb *cmd;
@@ -305,7 +308,7 @@ static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 		goto prune;
 
 	if (timestamp < cb->cmd->expire_unreachable) {
-		if (!cb->ref_commit)
+		if (cb->unreachable_expire_kind == UE_ALWAYS)
 			goto prune;
 		if (unreachable(cb, old, osha1) || unreachable(cb, new, nsha1))
 			goto prune;
@@ -332,12 +335,27 @@ static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 	return 0;
 }
 
+static int push_tip_to_list(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
+{
+	struct commit_list **list = cb_data;
+	struct commit *tip_commit;
+	if (flags & REF_ISSYMREF)
+		return 0;
+	tip_commit = lookup_commit_reference_gently(sha1, 1);
+	if (!tip_commit)
+		return 0;
+	commit_list_insert(tip_commit, list);
+	return 0;
+}
+
 static int expire_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 {
 	struct cmd_reflog_expire_cb *cmd = cb_data;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
 	char *log_file, *newlog_path = NULL;
+	struct commit *tip_commit;
+	struct commit_list *tips;
 	int status = 0;
 
 	memset(&cb, 0, sizeof(cb));
@@ -357,18 +375,49 @@ static int expire_reflog(const char *ref, const unsigned char *sha1, int unused,
 		cb.newlog = fopen(newlog_path, "w");
 	}
 
-	cb.ref_commit = lookup_commit_reference_gently(sha1, 1);
-	cb.ref = ref;
 	cb.cmd = cmd;
-	if (cb.ref_commit) {
-		cb.mark_list = NULL;
-		commit_list_insert(cb.ref_commit, &cb.mark_list);
+
+	if (!cmd->expire_unreachable || !strcmp(ref, "HEAD")) {
+		tip_commit = NULL;
+		cb.unreachable_expire_kind = UE_HEAD;
+	} else {
+		tip_commit = lookup_commit_reference_gently(sha1, 1);
+		if (!tip_commit)
+			cb.unreachable_expire_kind = UE_ALWAYS;
+		else
+			cb.unreachable_expire_kind = UE_NORMAL;
+	}
+
+	if (cmd->expire_unreachable <= cmd->expire_total)
+		cb.unreachable_expire_kind = UE_ALWAYS;
+
+	cb.mark_list = NULL;
+	tips = NULL;
+	if (cb.unreachable_expire_kind != UE_ALWAYS) {
+		if (cb.unreachable_expire_kind == UE_HEAD) {
+			struct commit_list *elem;
+			for_each_ref(push_tip_to_list, &tips);
+			for (elem = tips; elem; elem = elem->next)
+				commit_list_insert(elem->item, &cb.mark_list);
+		} else {
+			commit_list_insert(tip_commit, &cb.mark_list);
+		}
 		cb.mark_limit = cmd->expire_total;
 		mark_reachable(&cb);
 	}
+
 	for_each_reflog_ent(ref, expire_reflog_ent, &cb);
-	if (cb.ref_commit)
-		clear_commit_marks(cb.ref_commit, REACHABLE);
+
+	if (cb.unreachable_expire_kind != UE_ALWAYS) {
+		if (cb.unreachable_expire_kind == UE_HEAD) {
+			struct commit_list *elem;
+			for (elem = tips; elem; elem = elem->next)
+				clear_commit_marks(tip_commit, REACHABLE);
+			free_commit_list(tips);
+		} else {
+			clear_commit_marks(tip_commit, REACHABLE);
+		}
+	}
  finish:
 	if (cb.newlog) {
 		if (fclose(cb.newlog)) {

t/t7700-repack.sh

@@ -8,6 +8,7 @@ test_expect_success 'objects in packs marked .keep are not repacked' '
 	echo content1 > file1 &&
 	echo content2 > file2 &&
 	git add . &&
+	test_tick &&
 	git commit -m initial_commit &&
 	# Create two packs
 	# The first pack will contain all of the objects except one
@@ -40,6 +41,7 @@ test_expect_success 'loose objects in alternate ODB are not repacked' '
 	echo content3 > file3 &&
 	objsha1=$(GIT_OBJECT_DIRECTORY=alt_objects git hash-object -w file3) &&
 	git add file3 &&
+	test_tick &&
 	git commit -m commit_file3 &&
 	git repack -a -d -l &&
 	git prune-packed &&
@@ -73,6 +75,7 @@ test_expect_success 'packed obs in alt ODB are repacked when local repo has pack
 	rm -f .git/objects/pack/* &&
 	echo new_content >> file1 &&
 	git add file1 &&
+	test_tick &&
 	git commit -m more_content &&
 	git repack &&
 	git repack -a -d &&
@@ -118,8 +121,8 @@ test_expect_success 'packed unreachable obs in alternate ODB are not loosened' '
 	mv .git/objects/pack/* alt_objects/pack/ &&
 	csha1=$(git rev-parse HEAD^{commit}) &&
 	git reset --hard HEAD^ &&
-	sleep 1 &&
-	git reflog expire --expire=now --expire-unreachable=now --all &&
+	test_tick &&
+	git reflog expire --expire=$test_tick --expire-unreachable=$test_tick --all &&
 	# The pack-objects call on the next line is equivalent to
 	# git repack -A -d without the call to prune-packed
 	git pack-objects --honor-pack-keep --non-empty --all --reflog \
@@ -156,7 +159,7 @@ test_expect_success 'objects made unreachable by grafts only are kept' '
 	H1=$(git rev-parse HEAD^) &&
 	H2=$(git rev-parse HEAD^^) &&
 	echo "$H0 $H2" > .git/info/grafts &&
-	git reflog expire --expire=now --expire-unreachable=now --all &&
+	git reflog expire --expire=$test_tick --expire-unreachable=$test_tick --all &&
 	git repack -a -d &&
 	git cat-file -t $H1
 	'

t/t7701-repack-unpack-unreachable.sh

@@ -11,17 +11,20 @@ tsha1=
 test_expect_success '-A with -d option leaves unreachable objects unpacked' '
 	echo content > file1 &&
 	git add . &&
+	test_tick &&
 	git commit -m initial_commit &&
 	# create a transient branch with unique content
 	git checkout -b transient_branch &&
 	echo more content >> file1 &&
 	# record the objects created in the database for file, commit, tree
 	fsha1=$(git hash-object file1) &&
+	test_tick &&
 	git commit -a -m more_content &&
 	csha1=$(git rev-parse HEAD^{commit}) &&
 	tsha1=$(git rev-parse HEAD^{tree}) &&
 	git checkout master &&
 	echo even more content >> file1 &&
+	test_tick &&
 	git commit -a -m even_more_content &&
 	# delete the transient branch
 	git branch -D transient_branch &&
@@ -34,9 +37,11 @@ test_expect_success '-A with -d option leaves unreachable objects unpacked' '
 	git show $fsha1 &&
 	git show $csha1 &&
 	git show $tsha1 &&
-	# now expire the reflog
-	sleep 1 &&
-	git reflog expire --expire-unreachable=now --all &&
+	# now expire the reflog, while keeping reachable ones but expiring
+	# unreachables immediately
+	test_tick &&
+	sometimeago=$(( $test_tick - 10000 )) &&
+	git reflog expire --expire=$sometimeago --expire-unreachable=$test_tick --all &&
 	# and repack
 	git repack -A -d -l &&
 	# verify objects are retained unpacked
@@ -71,7 +76,7 @@ test_expect_success '-A without -d option leaves unreachable objects packed' '
 	test 1 = $(ls -1 .git/objects/pack/pack-*.pack | wc -l) &&
 	packfile=$(ls .git/objects/pack/pack-*.pack) &&
 	git branch -D transient_branch &&
-	sleep 1 &&
+	test_tick &&
 	git repack -A -l &&
 	test ! -f "$fsha1path" &&
 	test ! -f "$csha1path" &&