fix(cli): validate the complete TTS speed argument (#5264)

packages/cli/src/commands/tts.test.ts

@@ -1,4 +1,5 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { runCommand } from "citty";
 import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
@@ -44,6 +45,41 @@ describe("tts command", () => {
     );
   });
 
+  it.each(["0.05", "1x", "1.5junk", "1 2", "", " ", "NaN", "Infinity", "0", "-1", "3.01"])(
+    "rejects invalid speed %j before synthesis",
+    async (speed) => {
+      const errors = vi.spyOn(console, "error").mockImplementation(() => {});
+      await expect(
+        runCommand(ttsCommand, { rawArgs: ["Hello", "--speed", speed, "--json"] }),
+      ).rejects.toThrow();
+      expect(synthesizeMock).not.toHaveBeenCalled();
+      expect(errors.mock.calls.flat().join(" ")).toContain("between 0.1 and 3.0");
+    },
+  );
+
+  it.each([
+    ["0.1", 0.1],
+    ["3", 3],
+    ["1e-1", 0.1],
+    [" 1.25 ", 1.25],
+  ])("uses the complete valid speed %j", async (speed, expected) => {
+    await runCommand(ttsCommand, { rawArgs: ["Hello", "--speed", speed, "--json"] });
+    expect(synthesizeMock).toHaveBeenCalledWith(
+      "Hello",
+      expect.any(String),
+      expect.objectContaining({ speed: expected }),
+    );
+  });
+
+  it("defaults the speed only when the argument is omitted", async () => {
+    await runCommand(ttsCommand, { rawArgs: ["Hello", "--json"] });
+    expect(synthesizeMock).toHaveBeenCalledWith(
+      "Hello",
+      expect.any(String),
+      expect.objectContaining({ speed: 1 }),
+    );
+  });
+
   it("rejects text words with --text-file even under --list", async () => {
     const input = join(dir, "script.txt");
     writeFileSync(input, "From the file\n");

packages/cli/src/commands/tts.ts

@@ -121,9 +121,9 @@ export default defineCommand({
     // ── Resolve output path ───────────────────────────────────────────
     const output = resolve(args.output ?? "speech.wav");
     const voice = args.voice ?? DEFAULT_VOICE;
-    const speed = args.speed ? parseFloat(args.speed) : 1.0;
+    const speed = args.speed === undefined ? 1.0 : Number(args.speed);
 
-    if (isNaN(speed) || speed <= 0 || speed > 3) {
+    if (!Number.isFinite(speed) || speed < 0.1 || speed > 3) {
       console.error(c.error("Speed must be a number between 0.1 and 3.0"));
       failCommand();
     }