[master] 5651267d4 vrt: Harmonize regexp error messages

[Dridi Boukelmoune]

commit 5651267d4aa5fd9258d7385b7f6fd3e28a008d8c
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Apr 9 17:19:02 2025 +0200

    vrt: Harmonize regexp error messages
    
    Better diff with the --patience option.

diff --git a/bin/varnishd/cache/cache_vrt_re.c b/bin/varnishd/cache/cache_vrt_re.c
index 58d980d1b..5ad281f1d 100644
--- a/bin/varnishd/cache/cache_vrt_re.c
+++ b/bin/varnishd/cache/cache_vrt_re.c
@@ -61,11 +61,23 @@ VPI_re_fini(vre_t *rep)
 		VRE_free(&vv);
 }
 
-VCL_BOOL
-VRT_re_match(VRT_CTX, const char *s, VCL_REGEX re)
+static void
+re_fail(VRT_CTX, const char *pfx, int res)
 {
 	struct vsb vsb[1];
 	char errbuf[VRE_ERROR_LEN];
+
+	assert(res < VRE_ERROR_NOMATCH);
+	AN(VSB_init(vsb, errbuf, sizeof errbuf));
+	AZ(VRE_error(vsb, res));
+	AZ(VSB_finish(vsb));
+	VSB_fini(vsb);
+	VRT_fail(ctx, "%sRegexp matching failed: %s", pfx, errbuf);
+}
+
+VCL_BOOL
+VRT_re_match(VRT_CTX, const char *s, VCL_REGEX re)
+{
 	int i;
 
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
@@ -75,13 +87,8 @@ VRT_re_match(VRT_CTX, const char *s, VCL_REGEX re)
 	i = VRE_match(re, s, 0, 0, &cache_param->vre_limits);
 	if (i >= 0)
 		return (1);
-	if (i < VRE_ERROR_NOMATCH ) {
-		AN(VSB_init(vsb, errbuf, sizeof errbuf));
-		AZ(VRE_error(vsb, i));
-		AZ(VSB_finish(vsb));
-		VSB_fini(vsb);
-		VRT_fail(ctx, "Regexp matching failed: %s", errbuf);
-	}
+	if (i < VRE_ERROR_NOMATCH)
+		re_fail(ctx, "", i);
 	return (0);
 }
 
@@ -106,7 +113,7 @@ VRT_regsub(VRT_CTX, int all, VCL_STRING str, VCL_REGEX re, VCL_STRING sub)
 	res = WS_VSB_finish(vsb, ctx->ws, NULL);
 
 	if (i < VRE_ERROR_NOMATCH)
-		VRT_fail(ctx, "regsub: Regexp matching returned %d", i);
+		re_fail(ctx, "regsub: ", i);
 	else if (res == NULL)
 		VRT_fail(ctx, "regsub: Out of workspace");
 	else if (i > 0)