ipn/ipnlocal/netmapcache: ensure cache updates preserve unchanged data (#18590)

Found by @cmol. When rewriting the same value into the cache, we were dropping the unchanged keys, resulting in the cache being pruned incorrectly. Also update the tests to catch this. Updates #12639 Change-Id: Iab67e444eb7ddc22ccc680baa2f6a741a00eb325 Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>
2026-02-03 07:55:41 -08:00
parent 77f5200164
commit 14322713a5
2 changed files with 20 additions and 0 deletions
@@ -86,6 +86,7 @@ func (c *Cache) writeJSON(ctx context.Context, key string, v any) error {
 	// this at all?
 	last, ok := c.lastWrote[key]
 	if ok && cacheDigest(j) == last.digest {
+		c.wantKeys.Add(key)
 		return nil
 	}