Merge branch 'sg/rerere-gc-old-still-used'

* sg/rerere-gc-old-still-used:
  rerere: fix overeager gc
  mingw_utime(): handle NULL times parameter

builtin/rerere.c

@@ -19,6 +19,12 @@ static time_t rerere_created_at(const char *name)
 	return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
 }
 
+static time_t rerere_last_used_at(const char *name)
+{
+	struct stat st;
+	return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
+}
+
 static void unlink_rr_item(const char *name)
 {
 	unlink(rerere_path(name, "thisimage"));
@@ -53,11 +59,16 @@ static void garbage_collect(struct string_list *rr)
 	while ((e = readdir(dir))) {
 		if (is_dot_or_dotdot(e->d_name))
 			continue;
-		then = rerere_created_at(e->d_name);
-		if (!then)
-			continue;
-		cutoff = (has_rerere_resolution(e->d_name)
-			  ? cutoff_resolve : cutoff_noresolve);
+
+		then = rerere_last_used_at(e->d_name);
+		if (then) {
+			cutoff = cutoff_resolve;
+		} else {
+			then = rerere_created_at(e->d_name);
+			if (!then)
+				continue;
+			cutoff = cutoff_noresolve;
+		}
 		if (then < now - cutoff * 86400)
 			string_list_append(&to_remove, e->d_name);
 	}

compat/mingw.c

@@ -304,8 +304,13 @@ int mingw_utime (const char *file_name, const struct utimbuf *times)
 		goto revert_attrs;
 	}
 
-	time_t_to_filetime(times->modtime, &mft);
-	time_t_to_filetime(times->actime, &aft);
+	if (times) {
+		time_t_to_filetime(times->modtime, &mft);
+		time_t_to_filetime(times->actime, &aft);
+	} else {
+		GetSystemTimeAsFileTime(&mft);
+		aft = mft;
+	}
 	if (!SetFileTime((HANDLE)_get_osfhandle(fh), NULL, &aft, &mft)) {
 		errno = EINVAL;
 		rc = -1;

rerere.c

@@ -378,7 +378,13 @@ static int merge(const char *name, const char *path)
 	}
 	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
 	if (!ret) {
-		FILE *f = fopen(path, "w");
+		FILE *f;
+
+		if (utime(rerere_path(name, "postimage"), NULL) < 0)
+			warning("failed utime() on %s: %s",
+					rerere_path(name, "postimage"),
+					strerror(errno));
+		f = fopen(path, "w");
 		if (!f)
 			return error("Could not open %s: %s", path,
 				     strerror(errno));

t/t4200-rerere.sh

@@ -132,6 +132,8 @@ test_expect_success 'commit succeeds' \
 
 test_expect_success 'recorded postimage' "test -f $rr/postimage"
 
+oldmtimepost=$(test-chmtime -v -60 $rr/postimage |cut -f 1)
+
 test_expect_success 'another conflicting merge' '
 	git checkout -b third master &&
 	git show second^:a1 | sed "s/To die: t/To die! T/" > a1 &&
@@ -144,6 +146,11 @@ test_expect_success 'rerere kicked in' "! grep ^=======$ a1"
 
 test_expect_success 'rerere prefers first change' 'test_cmp a1 expect'
 
+test_expect_success 'rerere updates postimage timestamp' '
+	newmtimepost=$(test-chmtime -v +0 $rr/postimage |cut -f 1) &&
+	test $oldmtimepost -lt $newmtimepost
+'
+
 rm $rr/postimage
 echo "$sha1	a1" | perl -pe 'y/\012/\000/' > .git/MERGE_RR
 
@@ -165,15 +172,16 @@ just_over_15_days_ago=$((-1-15*86400))
 almost_60_days_ago=$((60-60*86400))
 just_over_60_days_ago=$((-1-60*86400))
 
-test-chmtime =$almost_60_days_ago $rr/preimage
+test-chmtime =$just_over_60_days_ago $rr/preimage
+test-chmtime =$almost_60_days_ago $rr/postimage
 test-chmtime =$almost_15_days_ago $rr2/preimage
 
 test_expect_success 'garbage collection (part1)' 'git rerere gc'
 
-test_expect_success 'young records still live' \
+test_expect_success 'young or recently used records still live' \
 	"test -f $rr/preimage && test -f $rr2/preimage"
 
-test-chmtime =$just_over_60_days_ago $rr/preimage
+test-chmtime =$just_over_60_days_ago $rr/postimage
 test-chmtime =$just_over_15_days_ago $rr2/preimage
 
 test_expect_success 'garbage collection (part2)' 'git rerere gc'