Adds support for corepack install -g yarn

sources/specUtils.ts

@@ -11,16 +11,16 @@ export function parseSpec(raw: unknown, source: string, {enforceExactVersion = t
   if (typeof raw !== `string`)
     throw new UsageError(`Invalid package manager specification in ${source}; expected a string`);
 
-  const match = raw.match(/^(?!_)(.+)@(.+)$/);
-  if (match === null || (enforceExactVersion && !semver.valid(match[2])))
+  const match = raw.match(/^(?!_)(.+)(@(.+))?$/);
+  if (match === null || (enforceExactVersion && (!match[2] || !semver.valid(match[2]))))
     throw new UsageError(`Invalid package manager specification in ${source}; expected a semver version${enforceExactVersion ? `` : `, range, or tag`}`);
 
   if (!isSupportedPackageManager(match[1]))
     throw new UsageError(`Unsupported package manager specification (${match})`);
 
   return {
     name: match[1],
-    range: match[2],
+    range: match[2] ?? `*`,
   };
 }
 
@@ -57,7 +57,7 @@ export async function findProjectSpec(initialCwd: string, locator: Locator, {tra
       case `NoProject`:
       case `NoSpec`: {
         return fallbackLocator;
-      } break;
+      }
 
       case `Found`: {
         if (result.spec.name !== locator.name) {
@@ -69,7 +69,7 @@ export async function findProjectSpec(initialCwd: string, locator: Locator, {tra
         } else {
           return result.spec;
         }
-      } break;
+      }
     }
   }
 }

tests/main.test.ts

@@ -267,6 +267,25 @@ it(`should allow to call "corepack install -g" with a tag`, async () => {
   });
 });
 
+it(`should allow to call "corepack install -g" without any range`, async () => {
+  await xfs.mktempPromise(async cwd => {
+    await expect(runCli(cwd, [`install`, `-g`, `yarn`])).resolves.toMatchObject({
+      exitCode: 0,
+      stderr: ``,
+    });
+
+    await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {
+      // empty package.json file
+    });
+
+    await expect(runCli(cwd, [`yarn`, `--version`])).resolves.toMatchObject({
+      stdout: expect.not.stringMatching(/^[123]\./),
+      stderr: ``,
+      exitCode: 0,
+    });
+  });
+});
+
 it(`should allow to call "corepack install" without arguments within a configured project`, async () => {
   await xfs.mktempPromise(async cwd => {
     await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {