From 3a41ff8d0cbfd0a7891697acf162f0b5800550ce Mon Sep 17 00:00:00 2001
From: Bryce Kwon <bryce@brycekwon.com>
Date: Sat, 31 Oct 2026 18:26:03 -1000
Subject: Keep a scan with a negative ttl for good

"The cache" promises that a negative ttl never expires, but no age was
ever below a negative cache-scan-ttl, so every request started a
background rescan.
---
 MANUAL.txt           |  6 ++++--
 source/cgit.c        |  3 ++-
 tests/t0003-cache.sh | 21 +++++++++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/MANUAL.txt b/MANUAL.txt
index 473a6e5..1205db1 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -69,8 +69,10 @@ cache-root::
 
 cache-scan-ttl::
 	Number which specifies the time-to-live, in minutes, for the result of
-	scanning a path for git repositories. Default value: "15". See also:
-	"The cache".
+	scanning a path for git repositories. It is read when scan-path runs,
+	along with "cache-size" and "cache-root", so all three must be defined
+	prior to scan-path to apply to the scan. Default value: "15". See also:
+	"scan-path", "The cache".
 
 cache-size::
 	The maximum number of entries in the cgit cache. When set to "0",
diff --git a/source/cgit.c b/source/cgit.c
index 254062f..41bbad3 100644
--- a/source/cgit.c
+++ b/source/cgit.c
@@ -452,8 +452,9 @@ static void process_cached_repolist(const char *path)
 
 	config_file_parse(cached_rc.buf, apply_config);
 
+	// A negative ttl never expires, the same as for a cached page.
 	age = time(NULL) - st.st_mtime;
-	if (age <= (ctx.cfg.cache_scan_ttl * 60))
+	if (ctx.cfg.cache_scan_ttl < 0 || age <= (ctx.cfg.cache_scan_ttl * 60))
 		goto out;
 
 	// The list just parsed is stale but usable, so a child rebuilds it
diff --git a/tests/t0003-cache.sh b/tests/t0003-cache.sh
index e63efa0..fa72015 100755
--- a/tests/t0003-cache.sh
+++ b/tests/t0003-cache.sh
@@ -434,4 +434,25 @@ test_expect_success 'a config that scans differently keeps its own list' '
 	! grep ">two</a>" strict.out
 '
 
+# A negative ttl never expires, so a list however old is served and kept. A
+# rebuild runs in a child holding the request's copy of fd 9, so cat reaching
+# the end of that pipe means any rebuild is done, as the positive ttl after
+# it shows.
+test_expect_success 'a negative cache-scan-ttl never expires the list' '
+	{
+		echo "cache-scan-ttl=-1" &&
+		cat scanrc
+	} >foreverrc &&
+	{
+		echo "repo.url=kept" &&
+		echo "repo.path=$PWD/scanned/one/.git"
+	} >>"cache5/$scanned_rc" &&
+	touch -t 200001010000 "cache5/$scanned_rc" &&
+	cgit_rc foreverrc "url=" 9>&1 >forever.out | cat &&
+	grep ">kept</a>" forever.out &&
+	grep "^repo.url=kept$" "cache5/$scanned_rc" &&
+	cgit_rc scanrc "url=" 9>&1 >/dev/null | cat &&
+	! grep "^repo.url=kept$" "cache5/$scanned_rc"
+'
+
 test_done
-- 
cgit 2.12.1