Syntax-highlight Edit, Write, and Read tool calls (#1218)

Highlighting reuses the existing code-block tokenizer and LRU cache, runs lazily on expand, and falls back to plain text above a size cap so a large Read can't stall the main thread. The diff highlighter reconstructs the old and new file text by position rather than from @@ line ranges, so diffs that arrive without real hunk headers still highlight. Read content is normalized server-side: the cat -n line-number gutter some providers emit is stripped so content is uniformly raw source, with the first line number surfaced as offset for the client to rebuild the gutter.
2026-05-29 14:51:14 +08:00
parent 25d6fc8515
commit 38f0560f9b
12 changed files with 661 additions and 77 deletions
@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import { highlightDiffLines } from "./diff-highlight";
+import { buildLineDiff, parseUnifiedDiff, type DiffLine } from "./tool-call-parsers";
+
+function joinTokens(line: DiffLine): string {
+  return (line.tokens ?? []).map((token) => token.text).join("");
+}
+
+describe("highlightDiffLines", () => {
+  it("attaches tokens to add/remove/context lines for a supported language", () => {
+    const diff = buildLineDiff("const a = 1;\nconst b = 2;", "const a = 1;\nconst b = 3;");
+    const result = highlightDiffLines(diff, "/repo/src/index.ts");
+
+    const context = result.find((line) => line.type === "context");
+    const remove = result.find((line) => line.type === "remove");
+    const add = result.find((line) => line.type === "add");
+
+    expect(context?.tokens).toBeDefined();
+    expect(remove?.tokens).toBeDefined();
+    expect(add?.tokens).toBeDefined();
+    // Tokens reconstruct the code with the diff marker excluded.
+    expect(joinTokens(context as DiffLine)).toBe("const a = 1;");
+    expect(joinTokens(remove as DiffLine)).toBe("const b = 2;");
+    expect(joinTokens(add as DiffLine)).toBe("const b = 3;");
+    // A keyword token is recognised (proves real highlighting, not pass-through).
+    expect(add?.tokens?.some((token) => token.style === "keyword")).toBe(true);
+  });
+
+  it("highlights a Codex-style unified diff with bare @@ headers (no line ranges)", () => {
+    const unified = ["@@", "-const x = 1;", "+const x = 2;", " const y = 3;"].join("\n");
+    const result = highlightDiffLines(parseUnifiedDiff(unified), "/repo/a.ts");
+
+    const remove = result.find((line) => line.type === "remove");
+    const add = result.find((line) => line.type === "add");
+    const context = result.find((line) => line.type === "context");
+    expect(joinTokens(remove as DiffLine)).toBe("const x = 1;");
+    expect(joinTokens(add as DiffLine)).toBe("const x = 2;");
+    expect(joinTokens(context as DiffLine)).toBe("const y = 3;");
+    expect(result.find((line) => line.type === "header")?.tokens).toBeUndefined();
+  });
+
+  it("returns lines unchanged for an unsupported language", () => {
+    const diff = buildLineDiff("a", "b");
+    const result = highlightDiffLines(diff, "/repo/notes.unknownext");
+    expect(result).toBe(diff);
+    expect(result.every((line) => line.tokens === undefined)).toBe(true);
+  });
+
+  it("returns lines unchanged when there is no file path", () => {
+    const diff = buildLineDiff("a", "b");
+    expect(highlightDiffLines(diff, undefined)).toBe(diff);
+  });
+});