From f6885fecfaa511f2794b8426950a3a41fe03982d Mon Sep 17 00:00:00 2001
From: Davide Scaini <davide.scaini@alumni.cern>
Date: Sun, 26 Apr 2026 15:05:33 +0200
Subject: [PATCH] fix(mobile): use split/join for import() patch, gate behind
 Chrome<63 check
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The regex /\bimport\(/g inside a template literal corrupts \b into a
backspace and \( into (, producing an unterminated-group SyntaxError in the
WebView. Use split().join() instead — no escape sequences, no corruption.

Modern WebViews (Chrome 63+) keep the original clean <script>-tag path.
Old WebViews (Karoo Chrome 61) take the fetch+patch+Blob path.
---
 mobile/extraction/PyodideWebView.tsx | 69 +++++++++++++++-------------
 1 file changed, 38 insertions(+), 31 deletions(-)

diff --git a/mobile/extraction/PyodideWebView.tsx b/mobile/extraction/PyodideWebView.tsx
index 7b18f45..d69d7c9 100644
--- a/mobile/extraction/PyodideWebView.tsx
+++ b/mobile/extraction/PyodideWebView.tsx
@@ -77,40 +77,47 @@ var initError     = null;
   try {
     _post({ type: 'progress', msg: 'Loading Python runtime…' });
 
-    // Chrome <63 (e.g. Karoo WebView 61) cannot parse the dynamic import()
-    // syntax that Pyodide uses to load pyodide.asm.js.  The parser rejects
-    // the whole file before it runs, so loadPyodide is never defined.
-    //
-    // Fix: fetch pyodide.js as text, replace every "import(" with a
-    // script-tag–based loader that Chrome 61 can execute, then inject the
-    // patched code via a Blob URL.  The Blob script is never parsed by the
-    // module-aware pre-scanner, so the import keyword is invisible to it.
-    window.__loadScript = function(url) {
-      return new Promise(function(res, rej) {
+    // Chrome <63 cannot parse dynamic import() — a parse-time SyntaxError
+    // prevents loadPyodide from ever being defined.  Detect this once and
+    // use a patched loader only for those old WebViews.
+    var chromeVer = (navigator.userAgent.match(/Chrome\\/([0-9]+)/) || [])[1];
+    var needsPatch = chromeVer && parseInt(chromeVer) < 63;
+
+    if (needsPatch) {
+      // Fetch pyodide.js as text and replace every "import(" with a
+      // script-tag shim before injecting via Blob URL.  Using split/join
+      // avoids regex escape sequences, which template literals corrupt.
+      // Node.js import("path") calls are guarded by IN_NODE and never run.
+      window.__loadScript = function(url) {
+        return new Promise(function(res, rej) {
+          var s = document.createElement('script');
+          s.src = url;
+          s.onload = res;
+          s.onerror = function() { rej(new Error('Failed to load ' + url)); };
+          document.head.appendChild(s);
+        });
+      };
+      var pyResp = await fetch(_CDN + 'pyodide.js');
+      if (!pyResp.ok) throw new Error('Could not fetch pyodide.js (' + pyResp.status + ')');
+      var pyCode = await pyResp.text();
+      pyCode = pyCode.split('import(').join('__loadScript(');
+      await new Promise(function(res, rej) {
+        var blob = new Blob([pyCode], { type: 'application/javascript' });
+        var blobUrl = URL.createObjectURL(blob);
         var s = document.createElement('script');
-        s.src = url;
-        s.onload = res;
-        s.onerror = function() { rej(new Error('Failed to load ' + url)); };
+        s.src = blobUrl;
+        s.onload = function() { URL.revokeObjectURL(blobUrl); res(); };
+        s.onerror = function() { URL.revokeObjectURL(blobUrl); rej(new Error('Failed to execute patched pyodide.js')); };
         document.head.appendChild(s);
       });
-    };
-
-    var pyResp = await fetch(_CDN + 'pyodide.js');
-    if (!pyResp.ok) throw new Error('Could not fetch pyodide.js (' + pyResp.status + ')');
-    var pyCode = await pyResp.text();
-    // Replace all dynamic import() calls.  Node.js-only paths (importing
-    // "path", "fs", etc.) are guarded by IN_NODE and never run in WebView.
-    pyCode = pyCode.replace(/\bimport\(/g, '__loadScript(');
-
-    await new Promise(function(res, rej) {
-      var blob = new Blob([pyCode], { type: 'application/javascript' });
-      var blobUrl = URL.createObjectURL(blob);
-      var s = document.createElement('script');
-      s.src = blobUrl;
-      s.onload = function() { URL.revokeObjectURL(blobUrl); res(); };
-      s.onerror = function() { URL.revokeObjectURL(blobUrl); rej(new Error('Failed to execute patched pyodide.js')); };
-      document.head.appendChild(s);
-    });
+    } else {
+      await new Promise(function(res, rej) {
+        var s = document.createElement('script');
+        s.src = _CDN + 'pyodide.js';
+        s.onload = res; s.onerror = rej;
+        document.head.appendChild(s);
+      });
+    }
 
     pyodide = await loadPyodide({ indexURL: _CDN });