fix: salvage truncated LLM JSON and make errors copyable

- Add repairTruncatedCardsJson to recover complete cards when output
  is cut off mid-card (e.g. token limit reached)
- Log raw LLM response to console on parse failure for debugging
- Make error panel text selectable and add "copy error" button

Change-Id: I4e76121138888234d42f84f3695cbbfd6beba886

main.ts

@@ -41,7 +41,7 @@ import {
   supportsStreaming,
   tokenLimitFieldForOpenAiChat,
 } from './src/providers';
-import { extractJson, normalizeCardsPayload } from './src/schema';
+import { extractJson, normalizeCardsPayload, repairTruncatedCardsJson } from './src/schema';
 import { createRafThrottledHandler, visibleTopProbeY } from './src/scroll';
 import {
   CACHE_SCHEMA_VERSION,
@@ -787,6 +787,7 @@ export const __test = {
   createRafThrottledHandler,
   createBatchRunState,
   extractJson,
+  repairTruncatedCardsJson,
   findLineForAnchor,
   folderPathsForTarget,
   createBatchStats,

src/cli.ts

@@ -196,6 +196,7 @@ export async function summarizeViaClaudeCode(
   }
 
   if (!resultText) {
+    console.warn('[parallel-reader] claude CLI returned no result. Full stdout:', stdout);
     throw new Error('claude CLI returned no result. Output:\n' + stdout.slice(0, 500));
   }
 

src/i18n.ts

@@ -31,6 +31,7 @@ export const STRINGS: Record<string, Record<string, string>> = {
     loadingGenerating: '对照阅读：让 LLM 读全文并自适应切段...',
     loadingSubtitle: '可以继续阅读原文，生成完成后会自动刷新右侧卡片。',
     errorTitle: '生成失败',
+    actionCopyError: '复制错误信息',
     emptyCard: '（未生成）',
     anchorMismatch: 'anchor 匹配失败，无法滚动联动',
     menuCopyMarkdown: '复制 Markdown',
@@ -189,6 +190,7 @@ export const STRINGS: Record<string, Record<string, string>> = {
     loadingGenerating: 'Parallel Reader: asking the LLM to read and segment the full note...',
     loadingSubtitle: 'You can keep reading. Cards will refresh when generation finishes.',
     errorTitle: 'Generation failed',
+    actionCopyError: 'Copy error',
     emptyCard: '(not generated)',
     anchorMismatch: 'Anchor did not match; scroll sync is unavailable',
     menuCopyMarkdown: 'Copy Markdown',

src/schema.ts

@@ -76,12 +76,54 @@ export function extractJson(text: string): string {
   return raw;
 }
 
+/**
+ * Attempt to salvage cards from truncated JSON.
+ * When the LLM output is cut off mid-card (e.g. token limit), the outer
+ * `{"cards":[...]}` never closes. This function locates the `"cards":[`
+ * array, finds every complete `{...}` object inside it (skipping the
+ * truncated tail), and reconstructs valid JSON.
+ */
+export function repairTruncatedCardsJson(text: string): string | null {
+  const match = text.match(/\{\s*"cards"\s*:\s*\[/);
+  if (!match || match.index === undefined) return null;
+
+  const afterArrayOpen = match.index + match[0].length;
+  const cardCandidates = collectJsonObjectCandidates(text.slice(afterArrayOpen));
+  const validCards: string[] = [];
+  for (const c of cardCandidates) {
+    try {
+      JSON.parse(c);
+      validCards.push(c);
+    } catch (_) {
+      /* skip malformed card */
+    }
+  }
+  if (validCards.length === 0) return null;
+  return '{"cards":[' + validCards.join(',') + ']}';
+}
+
 export function parseCardsJson(text: string, settings?: PluginSettings | null): RawCard[] {
   const jsonText = extractJson(text);
   let parsed;
   try {
     parsed = JSON.parse(jsonText);
   } catch (_e) {
+    // Attempt to salvage complete cards from truncated output
+    const repaired = repairTruncatedCardsJson(text);
+    if (repaired) {
+      try {
+        parsed = JSON.parse(repaired);
+        console.warn(
+          '[parallel-reader] LLM output was truncated; salvaged',
+          (parsed as { cards?: unknown[] }).cards?.length ?? 0,
+          'complete cards. Consider increasing max tokens.',
+        );
+        return normalizeCardsPayload(parsed);
+      } catch (_) {
+        /* repair failed, fall through to error */
+      }
+    }
+    console.warn('[parallel-reader] LLM returned non-JSON. Raw response:', text);
     throw new Error(
       translate(settings || null, 'errorLlmNonJson', {
         excerpt: (text || '').slice(0, 500),

src/view.ts

@@ -199,14 +199,25 @@ export class ParallelReaderView extends ItemView {
     if (this.errorMessage) {
       const state = container.createDiv({ cls: 'parallel-reader-state parallel-reader-error' });
       state.createEl('div', { text: this.plugin.t('errorTitle'), cls: 'parallel-reader-state-title' });
-      state.createEl('div', { text: this.errorMessage, cls: 'parallel-reader-state-subtitle' });
+      state.createEl('div', {
+        text: this.errorMessage,
+        cls: 'parallel-reader-state-subtitle parallel-reader-selectable',
+      });
+      const actions = state.createDiv({ cls: 'parallel-reader-error-actions' });
       addTextButton(
-        state,
+        actions,
         'refresh-cw',
         this.plugin.t('actionRegenerate'),
         () => this.plugin.runForFile(this.sourceFile, true),
         'parallel-reader-text-button',
       );
+      addTextButton(
+        actions,
+        'copy',
+        this.plugin.t('actionCopyError'),
+        () => copyToClipboard(this.errorMessage, this.plugin.t('actionCopyError')),
+        'parallel-reader-text-button',
+      );
       return;
     }
 

styles.css

@@ -288,6 +288,13 @@
   line-height: 1.6;
 }
 
+.parallel-reader-selectable {
+  user-select: text;
+  -webkit-user-select: text;
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
 .parallel-reader-error {
   border-color: var(--text-error, #e06c75);
 }
@@ -296,6 +303,12 @@
   color: var(--text-error, #e06c75);
 }
 
+.parallel-reader-error-actions {
+  display: flex;
+  gap: 8px;
+  margin-top: 8px;
+}
+
 .parallel-reader-spinner {
   width: 18px;
   height: 18px;

tests/modules.test.js

@@ -83,6 +83,30 @@ assert.strictEqual(extractJson('not json at all'), 'not json at all', 'non-JSON
 const nestedBraces = '{"cards":[{"title":"test {with} braces","anchor":"a","gist":"g","bullets":[]}]}';
 assert.deepStrictEqual(JSON.parse(extractJson(nestedBraces)).cards[0].title, 'test {with} braces');
 
+// ── schema.ts: repairTruncatedCardsJson ──
+
+const { repairTruncatedCardsJson } = t;
+
+assert.strictEqual(repairTruncatedCardsJson('not json'), null, 'non-cards text returns null');
+assert.strictEqual(repairTruncatedCardsJson(''), null, 'empty string returns null');
+assert.strictEqual(repairTruncatedCardsJson('{"cards":['), null, 'no complete cards returns null');
+
+const truncJson = '{"cards":[{"title":"A","anchor":"a","gist":"g","bullets":["b"]},{"title":"B","anchor":"x","gist":"trunc';
+const repaired = repairTruncatedCardsJson(truncJson);
+assert.ok(repaired, 'truncated JSON is repaired');
+const repairedParsed = JSON.parse(repaired);
+assert.strictEqual(repairedParsed.cards.length, 1, 'only complete card is kept');
+assert.strictEqual(repairedParsed.cards[0].title, 'A', 'salvaged card has correct title');
+
+const twoComplete = '{"cards":[{"title":"A","anchor":"a","gist":"g","bullets":["b"]},{"title":"B","anchor":"a2","gist":"g2","bullets":["c"]},{"title":"C","anch';
+const repairedTwo = JSON.parse(repairTruncatedCardsJson(twoComplete));
+assert.strictEqual(repairedTwo.cards.length, 2, 'two complete cards salvaged from three');
+
+// repairTruncatedCardsJson + normalizeCardsPayload integration
+const salvagedCards = normalizeCardsPayload(JSON.parse(repairTruncatedCardsJson(truncJson)));
+assert.strictEqual(salvagedCards.length, 1, 'repair + normalize produces valid cards');
+assert.strictEqual(salvagedCards[0].title, 'A', 'salvaged card has correct fields');
+
 // ── schema.ts: normalizeCardsPayload ──
 
 assert.deepStrictEqual(normalizeCardsPayload(null), [], 'null payload returns empty array');