Keep error pages out of the cache

2 files changed, 8 insertions, 3 deletions

diff --git a/source/cgit.c b/source/cgit.c
index ac8922b..12981c2 100644
--- a/source/cgit.c
+++ b/source/cgit.c
@@ -82,9 +82,8 @@ static void isolate_git_environment(void)
  */
 static NORETURN void die_routine(const char *msg, va_list params)
 {
-	// A page is rendered with stdout pointed at the cache file, so the
-	// message would otherwise be written there instead of to the visitor.
-	cache_abandon_fill();
+	// The error page abandons any cache fill in progress, so the message
+	// reaches the visitor rather than the cache file stdout points at.
 	cgit_vprint_error_page(400, "Bad request", msg, params);
 	exit(0);
 }
diff --git a/source/ui-shared.c b/source/ui-shared.c
index 066c25d..05fa30b 100644
--- a/source/ui-shared.c
+++ b/source/ui-shared.c
@@ -10,6 +10,7 @@
 
 #define USE_THE_REPOSITORY_VARIABLE
 
+#include "cache.h"
 #include "cgit.h"
 #include "html.h"
 #include "shared.h"
@@ -1293,6 +1294,11 @@ void cgit_print_error_page(int code, const char *msg, const char *fmt, ...)
 void cgit_vprint_error_page(int code, const char *msg, const char *fmt,
 			    va_list ap)
 {
+	// An error page describes a condition that may not outlast the slot
+	// holding it. A request naming a commit not yet pushed would cache its
+	// 404 under the never-expiring static ttl and keep serving it after
+	// the push, so the error is rendered straight to the visitor instead.
+	cache_abandon_fill();
 	ctx.page.status = code;
 	ctx.page.statusmsg = msg;
 	cgit_print_layout_start();