Better handle variants in traces (particularly syntax errors)

Author: grega

copydecks/en/copydeck.json

@@ -53,6 +53,17 @@
 
     "SyntaxError": {
       "variants": [
+        {
+          "if": {
+            "match_message": ["expected ':'"]
+          },
+          "title": "Missing colon (:) at the end",
+          "summary": "This line starts a block and needs a colon at {{loc}}: {{codeLine}}",
+          "why": "In Python, lines that start a block must end with a colon.",
+          "steps": [
+            "Add a colon (:) at the end of that line."
+          ]
+        },
         {
           "if": {
             "match_code": ["^(\\s*)(if|for|while|def|class|elif|else|try|except|with)\\b"],

src/adapters/pyodide.ts

@@ -21,6 +21,16 @@ export const pyodideAdapter: AdapterFn = (raw, code) => {
     if (cc) col = parseInt(cc[1], 10);
   }
 
+  if (!line) {
+    const m1 = raw.match(/on\s+line\s+(\d+)\s+of\s+([^\s:]+)(?::\s*([\s\S]*))?/i);
+    if (m1) {
+      line = parseInt(m1[1], 10);
+      file = m1[2];
+      const afterColon = (m1[3] || "").split(/\r?\n/);
+      const snippet = afterColon.find(s => s.trim() && !/^\s*\^+\s*$/.test(s));
+    }
+  }
+
   let name: string | undefined;
   const q = (message || "").match(/["']([^"']+)["']/);
   if (q) name = q[1];
@@ -38,10 +48,20 @@ export const pyodideAdapter: AdapterFn = (raw, code) => {
   };
 
   if (code && line) {
-    const lines = code.split(/\r?\n/);
-    t.codeLine = lines[line - 1]?.trim();
-    t.codeBefore = lines.slice(Math.max(0, line - 3), line - 1);
-    t.codeAfter = lines.slice(line, line + 2);
+    const codeLines = code.split(/\r?\n/);
+    t.codeLine = codeLines[line - 1]?.trim();
+    t.codeBefore = codeLines.slice(Math.max(0, line - 3), line - 1);
+    t.codeAfter = codeLines.slice(line, line + 2);
+  } else {
+    const m1 = raw.match(/on\s+line\s+\d+\s+of\s+[^\s:]+:(?:\s*([\s\S]*))?/i);
+    if (m1 && m1[1]) {
+      const snippet = m1[1].split(/\r?\n/).find(s => s.trim() && !/^\s*\^+\s*$/.test(s));
+      if (snippet) t.codeLine = snippet.trim();
+    }
   }
+
+  const looksLikeError = /Error\b/i.test(raw) || /Traceback/i.test(raw) || /pyodide/i.test(raw);
+  if (!looksLikeError) return null;
+
   return t;
 };

src/adapters/skulpt.ts

@@ -8,24 +8,26 @@ const lastLineTypeMessage = (raw: string) => {
 };
 
 export const skulptAdapter: AdapterFn = (raw, code) => {
-  if (!/skulpt/i.test(raw) && !/Traceback/i.test(raw)) {
-    // still try; skulpt often includes "on line X of", etc.
-  }
+  // Skulpt traces vary - we accept both "Traceback..." and editor summaries
   const { type, message, tail, lines } = lastLineTypeMessage(raw);
   let file: string | undefined, line: number | undefined, col: number | undefined;
 
+  // standard Python-style frames (Skulpt often emits these)
   for (const L of lines) {
     const mm = L.match(/File\s+"([^"]+)",\s+line\s+(\d+)/i);
     if (mm) {
       file = mm[1];
       line = parseInt(mm[2], 10);
     }
   }
+
   if (!line) {
-    const loc = tail.match(/\b(?:on|at)\s+line\s+(\d+)\s+(?:of|in)\s+([^\s:]+)\b/i);
-    if (loc) {
-      line = parseInt(loc[1], 10);
-      file = loc[2];
+    const m1 = raw.match(/on\s+line\s+(\d+)\s+of\s+([^\s:]+)(?::\s*([\s\S]*))?/i);
+    if (m1) {
+      line = parseInt(m1[1], 10);
+      file = m1[2];
+      const afterColon = (m1[3] || "").split(/\r?\n/);
+      const snippet = afterColon.find(s => s.trim() && !/^\s*\^+\s*$/.test(s));
     }
   }
 
@@ -46,10 +48,20 @@ export const skulptAdapter: AdapterFn = (raw, code) => {
   };
 
   if (code && line) {
-    const lines = code.split(/\r?\n/);
-    t.codeLine = lines[line - 1]?.trim();
-    t.codeBefore = lines.slice(Math.max(0, line - 3), line - 1);
-    t.codeAfter = lines.slice(line, line + 2);
+    const codeLines = code.split(/\r?\n/);
+    t.codeLine = codeLines[line - 1]?.trim();
+    t.codeBefore = codeLines.slice(Math.max(0, line - 3), line - 1);
+    t.codeAfter = codeLines.slice(line, line + 2);
+  } else {
+    const m1 = raw.match(/on\s+line\s+\d+\s+of\s+[^\s:]+:(?:\s*([\s\S]*))?/i);
+    if (m1 && m1[1]) {
+      const snippet = m1[1].split(/\r?\n/).find(s => s.trim() && !/^\s*\^+\s*$/.test(s));
+      if (snippet) t.codeLine = snippet.trim();
+    }
   }
+
+  const looksLikeError = /Error\b/i.test(raw) || /Traceback/i.test(raw) || /skulpt/i.test(raw);
+  if (!looksLikeError) return null;
+
   return t;
 };

src/engine.ts

@@ -13,15 +13,24 @@ export const loadCopydeck = (deck: CopyDeck) => (S.copy = deck);
 export const registerAdapter = (name: string, fn: (raw: string, code?: string) => Trace | null) =>
   (S.adapters[name] = fn);
 
+const isTrace = (x: unknown): x is Trace =>
+  !!x && typeof x === "object" && "raw" in (x as any) && "message" in (x as any);
+
 const coerceTrace = (input: string | Error | Trace, code?: string): Trace => {
-  if ((input as Trace).raw !== undefined) return input as Trace;
-  const raw = typeof input === "string" ? input : String((input as Error).stack || (input as Error).message || input);
+  if (isTrace(input)) return input as Trace;
+
+  const raw =
+    typeof input === "string"
+      ? input
+      : String((input as Error).stack || (input as Error).message || input);
+
   // try adapters in registration order
   for (const key of Object.keys(S.adapters)) {
     const t = S.adapters[key](raw, code);
     if (t) return t;
   }
-  // generic fallback
+
+  // fallback generic trace
   const lines = raw.trim().split(/\r?\n/).filter(Boolean);
   const tail = lines[lines.length - 1] || "";
   const m = tail.match(/^(\w+Error)\s*:\s*(.*)$/);
@@ -31,8 +40,9 @@ const coerceTrace = (input: string | Error | Trace, code?: string): Trace => {
     raw,
     runtime: "unknown"
   };
-  if (code) {
-    t.codeLine = code.split(/\r?\n/)[(t.line || 1) - 1]?.trim();
+
+  if (code && t.line) {
+    t.codeLine = code.split(/\r?\n/)[t.line - 1]?.trim();
   }
   return t;
 };
@@ -128,6 +138,7 @@ export const explain = (opts: ExplainOptions): ExplainResult => {
 
   const chosen = pickVariant(trace, code, audience);
   if (!chosen) {
+    // this generic fallback copy should live in the copydeck instead...
     return {
       trace,
       variantId: "Other/variants/0",