From ab9a29728b0247d8b0c5e5132656c76d79e3d72e Mon Sep 17 00:00:00 2001
From: Abarnaa Sree N <abarnaasree23@gmail.com>
Date: Mon, 10 Aug 2026 04:18:07 +0530
Subject: [PATCH] Warn when static HTML parser dependencies are unavailable
 (#465)

---
 cli/engine/engines/static-html/detect-html.mjs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/cli/engine/engines/static-html/detect-html.mjs b/cli/engine/engines/static-html/detect-html.mjs
index 482ba0cc3..e08589440 100644
--- a/cli/engine/engines/static-html/detect-html.mjs
+++ b/cli/engine/engines/static-html/detect-html.mjs
@@ -138,10 +138,21 @@ async function detectHtml(filePath, options = {}) {
         domutils,
       };
     });
-  } catch {
-    return detectText(html, filePath, options);
+  } catch (err) {
+  if (!globalThis.__impeccableStaticHtmlWarned) {
+    globalThis.__impeccableStaticHtmlWarned = true;
+
+    process.stderr.write(
+  'impeccable detect: DEGRADED - HTML parser modules unavailable ' +
+  '(htmlparser2, css-select, css-tree, domutils).\n' +
+  'Falling back to regex matching. Custom properties, selector matching and computed ' +
+  'contrast are NOT evaluated; findings are an undercount, not a clean bill of health.\n'
+);
   }
 
+  return detectText(html, filePath, options);
+}
+
   const resolvedPath = path.resolve(filePath);
   const fileDir = path.dirname(resolvedPath);
   const root = profileStep(profile, {