fix(canvas): use corepack for a2ui pnpm fallback

extensions/canvas/scripts/pnpm-runner.d.mts

@@ -1,5 +1,7 @@
 export interface PnpmRunnerParams {
   comSpec?: string;
+  cwd?: string;
+  env?: NodeJS.ProcessEnv;
   nodeArgs?: string[];
   nodeExecPath?: string;
   npmExecPath?: string;

extensions/canvas/scripts/pnpm-runner.mjs

@@ -2,6 +2,7 @@
  * Cross-platform pnpm command resolver used by Canvas build scripts.
  */
 import { accessSync, closeSync, constants, openSync, readSync, statSync } from "node:fs";
+import path from "node:path";
 
 const WINDOWS_UNSAFE_CMD_CHARS_RE = /[&|<>%\r\n]/;
 const PNPM_EXECUTABLE_RE = /^pnpm(?:-cli)?(?:\.(?:[cm]?js|cmd|exe))?$/;
@@ -48,6 +49,49 @@ function isExecutableFile(value) {
   }
 }
 
+function isFile(value) {
+  try {
+    return statSync(value).isFile();
+  } catch {
+    return false;
+  }
+}
+
+function resolvePathEnvKey(env) {
+  return Object.keys(env).find((key) => key.toLowerCase() === "path") ?? "PATH";
+}
+
+function findExecutableOnPath(command, envPath, platform, env, cwd) {
+  if (typeof envPath !== "string" || envPath.length === 0) {
+    return undefined;
+  }
+  const extensions =
+    platform === "win32"
+      ? (env[Object.keys(env).find((key) => key.toLowerCase() === "pathext") ?? "PATHEXT"] ??
+          ".COM;.EXE;.BAT;.CMD")
+          .split(";")
+          .filter(Boolean)
+          .map((extension) => extension.toLowerCase())
+      : [""];
+  const pathImpl = platform === "win32" ? path.win32 : path;
+  const pathDelimiter = platform === "win32" ? ";" : path.delimiter;
+  for (const directory of envPath.split(pathDelimiter)) {
+    if (!directory) {
+      continue;
+    }
+    const resolvedDirectory = pathImpl.isAbsolute(directory)
+      ? directory
+      : pathImpl.resolve(cwd, directory);
+    for (const extension of extensions) {
+      const candidate = pathImpl.join(resolvedDirectory, `${command}${extension}`);
+      if ((platform === "win32" ? isFile(candidate) : isExecutableFile(candidate))) {
+        return candidate;
+      }
+    }
+  }
+  return undefined;
+}
+
 function isNodeRunnablePnpmExecPath(value) {
   if (!isPnpmExecPath(value)) {
     return false;
@@ -129,6 +173,22 @@ export function resolvePnpmRunner(params = {}) {
 
   const pnpmArgs = params.pnpmArgs ?? [];
   const platform = params.platform ?? process.platform;
+  const env = params.env ?? process.env;
+  const envPath = env[platform === "win32" ? resolvePathEnvKey(env) : "PATH"];
+  const cwd = params.cwd ?? process.cwd();
+  const pnpmPath = findExecutableOnPath("pnpm", envPath, platform, env, cwd);
+  if (pnpmPath) {
+    return platform === "win32"
+      ? windowsCmdSpec(pnpmPath, pnpmArgs, params.comSpec ?? process.env.ComSpec ?? "cmd.exe")
+      : { args: pnpmArgs, command: pnpmPath, shell: false };
+  }
+  const corepackPath = findExecutableOnPath("corepack", envPath, platform, env, cwd);
+  if (corepackPath) {
+    const args = ["pnpm", ...pnpmArgs];
+    return platform === "win32"
+      ? windowsCmdSpec(corepackPath, args, params.comSpec ?? process.env.ComSpec ?? "cmd.exe")
+      : { args, command: corepackPath, shell: false };
+  }
   if (platform === "win32") {
     return windowsCmdSpec("pnpm.cmd", pnpmArgs, params.comSpec ?? process.env.ComSpec ?? "cmd.exe");
   }

extensions/canvas/scripts/pnpm-runner.test.ts

@@ -17,6 +17,7 @@ describe("canvas pnpm runner", () => {
     try {
       expect(
         resolvePnpmRunner({
+          env: { PATH: "" },
           npmExecPath,
           platform: "darwin",
           pnpmArgs: ["exec", "rolldown", "-c"],
@@ -40,6 +41,7 @@ describe("canvas pnpm runner", () => {
     try {
       expect(
         resolvePnpmRunner({
+          env: { PATH: "" },
           npmExecPath,
           platform: "darwin",
           pnpmArgs: ["exec", "rolldown", "-c"],
@@ -53,4 +55,55 @@ describe("canvas pnpm runner", () => {
       rmSync(tempDir, { recursive: true, force: true });
     }
   });
+
+  posixIt("uses Corepack when pnpm is not directly available on PATH", () => {
+    const tempDir = mkdtempSync(path.join(os.tmpdir(), "canvas-pnpm-runner-corepack-"));
+    const corepackPath = path.join(tempDir, "corepack");
+    writeFileSync(corepackPath, "#!/bin/sh\nexit 0\n");
+    chmodSync(corepackPath, 0o755);
+
+    try {
+      expect(
+        resolvePnpmRunner({
+          env: { PATH: tempDir },
+          npmExecPath: "",
+          platform: "darwin",
+          pnpmArgs: ["exec", "rolldown", "-c"],
+        }),
+      ).toEqual({
+        args: ["pnpm", "exec", "rolldown", "-c"],
+        command: corepackPath,
+        shell: false,
+      });
+    } finally {
+      rmSync(tempDir, { recursive: true, force: true });
+    }
+  });
+
+  posixIt("prefers a direct pnpm executable over Corepack", () => {
+    const tempDir = mkdtempSync(path.join(os.tmpdir(), "canvas-pnpm-runner-path-"));
+    const pnpmPath = path.join(tempDir, "pnpm");
+    const corepackPath = path.join(tempDir, "corepack");
+    writeFileSync(pnpmPath, "#!/bin/sh\nexit 0\n");
+    writeFileSync(corepackPath, "#!/bin/sh\nexit 0\n");
+    chmodSync(pnpmPath, 0o755);
+    chmodSync(corepackPath, 0o755);
+
+    try {
+      expect(
+        resolvePnpmRunner({
+          env: { PATH: tempDir },
+          npmExecPath: "",
+          platform: "darwin",
+          pnpmArgs: ["exec", "rolldown", "-c"],
+        }),
+      ).toEqual({
+        args: ["exec", "rolldown", "-c"],
+        command: pnpmPath,
+        shell: false,
+      });
+    } finally {
+      rmSync(tempDir, { recursive: true, force: true });
+    }
+  });
 });