fix: more escapes

frontend/src/conversation/MarkdownAnswer.codeSpans.test.ts

@@ -36,6 +36,34 @@ describe('citation rewriting spares code', () => {
     expect(text('inline ```code[0]``` end')).toBe('inline ```code[0]``` end');
   });
 
+  it('leaves a triple-backtick span that starts a line alone', () => {
+    // A backtick fence's info string cannot contain backticks, so this opens a
+    // code span, not an unclosed fence that swallows the rest of the answer.
+    expect(text('```code[0]``` and see [1]')).toBe(
+      '```code[0]``` and see [1](#cite-1)',
+    );
+  });
+
+  it('closes an inline span only on a run of its own length', () => {
+    // The `` run does not close the ` span, so `b[1]` is still code.
+    const source = 'Use `a`` b[1] more` end';
+    expect(text(source)).toBe(source);
+  });
+
+  it('recognises a fence closed on a CRLF line', () => {
+    expect(text('```js\r\nconst a = arr[0];\r\n```\r\nSee [1].')).toBe(
+      '```js\r\nconst a = arr[0];\r\n```\r\nSee [1](#cite-1).',
+    );
+  });
+
+  it('does not carry an inline span across a blank line', () => {
+    // The blank line ends the paragraph, so the backticks never pair and
+    // `bar[1]` is prose — which is how remark parses it too.
+    expect(text('a `foo\n\nbar[1]` end')).toBe(
+      'a `foo\n\nbar[1](#cite-1)` end',
+    );
+  });
+
   it('leaves an inline span that wraps a line alone', () => {
     expect(text('use `arr[0]\nnext` here')).toBe('use `arr[0]\nnext` here');
   });

frontend/src/conversation/MarkdownAnswer.tsx

@@ -26,11 +26,13 @@ import {
 // ```` fence closes only on ```` and nested fences stay masked. The
 // unterminated alternatives keep an open span matched too: answers stream in,
 // so a fence is open for most of its life and needs protecting the whole time,
-// not just once the closing fence arrives. Four-space indented blocks are
-// deliberately not masked — list continuation lines are indented the same way,
-// and masking those would drop real citations out of nested lists.
+// not just once the closing fence arrives. A backtick fence's info string may
+// not itself contain backticks, so a line that opens with an inline span stays
+// an inline span. Four-space indented blocks are deliberately not masked —
+// list continuation lines are indented the same way, and masking those would
+// drop real citations out of nested lists.
 const CODE_SPAN =
-  /(?<![^\n])[ \t]*(`{3,})[^`\n]*(?:[\s\S]*?\n[ \t]*\1`*[ \t]*(?![^\n])|[\s\S]*$)|(?<![^\n])[ \t]*(~{3,})[^\n]*(?:[\s\S]*?\n[ \t]*\2~*[ \t]*(?![^\n])|[\s\S]*$)|(`+)(?:[^\n]|\n(?![ \t]*\n))*?\3(?!`)|`+[^`\n]*$/g;
+  /(?<![^\n])[ \t]*(`{3,})[^`\n]*(?![^\n])(?:[\s\S]*?\n[ \t]*\1`*[ \t]*\r?(?![^\n])|[\s\S]*$)|(?<![^\n])[ \t]*(~{3,})[^\n]*(?:[\s\S]*?\n[ \t]*\2~*[ \t]*\r?(?![^\n])|[\s\S]*$)|(`+)(?:[^\n]|\n(?![ \t\r]*\n))*?(?<!`)\3(?!`)|`+[^`\n]*$/g;
 
 // ``\[ \]`` and ``\( \)`` LaTeX, which remark-math does not recognise.
 const LATEX_SPAN = /\\\[[\s\S]*?\\\]|\\\([\s\S]*?\\\)/g;