fix(install): detect package manager launcher names

scripts/preinstall-package-manager-warning.mjs

@@ -2,6 +2,10 @@
 import { pathToFileURL } from "node:url";
 
 const allowedLifecyclePackageManagers = new Set(["pnpm", "npm", "yarn", "bun"]);
+const lifecyclePackageManagerLauncherAliases = new Map([
+  ["yarnpkg", "yarn"],
+  ["yarn-berry", "yarn"],
+]);
 
 function normalizeEnvValue(value) {
   return typeof value === "string" ? value.trim() : "";
@@ -15,6 +19,31 @@ function normalizeLifecyclePackageManagerName(value) {
   return allowedLifecyclePackageManagers.has(normalized) ? normalized : null;
 }
 
+function detectLifecyclePackageManagerFromExecPath(value) {
+  const execPath = normalizeEnvValue(value).toLowerCase();
+  const executableName = execPath.split(/[\\/]/u).findLast((segment) => segment.length > 0) ?? "";
+  const launcherName = executableName.replace(/\.(?:c?js|mjs|cmd|ps1|exe)$/u, "");
+  const candidates = [launcherName, launcherName.replace(/-cli$/u, "")];
+
+  for (const candidate of candidates) {
+    if (/^yarn(?:pkg)?-\d/u.test(candidate)) {
+      return "yarn";
+    }
+
+    const aliasedPackageManager = lifecyclePackageManagerLauncherAliases.get(candidate);
+    if (aliasedPackageManager) {
+      return aliasedPackageManager;
+    }
+
+    const packageManager = normalizeLifecyclePackageManagerName(candidate);
+    if (packageManager) {
+      return packageManager;
+    }
+  }
+
+  return null;
+}
+
 /**
  * Detects the package manager running the current lifecycle script.
  */
@@ -25,21 +54,7 @@ export function detectLifecyclePackageManager(env = process.env) {
     return normalizeLifecyclePackageManagerName(userAgentMatch[1]);
   }
 
-  const execPath = normalizeEnvValue(env.npm_execpath).toLowerCase();
-  if (execPath.includes("pnpm")) {
-    return "pnpm";
-  }
-  if (execPath.includes("npm")) {
-    return "npm";
-  }
-  if (execPath.includes("yarn")) {
-    return "yarn";
-  }
-  if (execPath.includes("bun")) {
-    return "bun";
-  }
-
-  return null;
+  return detectLifecyclePackageManagerFromExecPath(env.npm_execpath);
 }
 
 /**

test/scripts/preinstall-package-manager-warning.test.ts

@@ -35,6 +35,46 @@ describe("detectLifecyclePackageManager", () => {
     ).toBe("pnpm");
   });
 
+  it("detects npm cli launchers from npm_execpath", () => {
+    expect(
+      detectLifecyclePackageManager({
+        npm_execpath: "C:\\Tools\\nodejs\\node_modules\\npm\\bin\\npm-cli.js",
+      }),
+    ).toBe("npm");
+  });
+
+  it("detects yarnpkg launchers from npm_execpath", () => {
+    expect(
+      detectLifecyclePackageManager({
+        npm_execpath: "C:\\Tools\\corepack\\yarnpkg.cmd",
+      }),
+    ).toBe("yarn");
+  });
+
+  it("detects versioned Yarn release launchers from npm_execpath", () => {
+    expect(
+      detectLifecyclePackageManager({
+        npm_execpath: "/work/project/.yarn/releases/yarn-4.5.0.cjs",
+      }),
+    ).toBe("yarn");
+  });
+
+  it("detects Yarn Berry release launchers from npm_execpath", () => {
+    expect(
+      detectLifecyclePackageManager({
+        npm_execpath: "/work/project/.yarn/releases/yarn-berry.cjs",
+      }),
+    ).toBe("yarn");
+  });
+
+  it("ignores package manager names in npm_execpath parent directories", () => {
+    expect(
+      detectLifecyclePackageManager({
+        npm_execpath: "/tmp/npm-cache/bin/yarn.js",
+      }),
+    ).toBe("yarn");
+  });
+
   it("ignores untrusted user-agent tokens with control characters", () => {
     expect(
       detectLifecyclePackageManager({