fix(use): do not throw on invalid packageManager

Author: aduh95

sources/specUtils.ts

@@ -132,16 +132,16 @@ function parsePackageJSON(packageJSONContent: CorepackPackageJSON) {
 }
 
 export async function setLocalPackageManager(cwd: string, info: PreparedPackageManagerInfo) {
-  const lookup = await loadSpec(cwd);
+  const lookup = await loadSpec(cwd, true);
 
   const content = lookup.type !== `NoProject`
     ? await fs.promises.readFile((lookup as FoundSpecResult).envFilePath ?? lookup.target, `utf8`)
     : ``;
 
   let previousPackageManager: string;
   let newContent: string;
-  if ((lookup as FoundSpecResult).envFilePath) {
-    const envKey = `COREPACK_DEV_ENGINES_${(lookup as FoundSpecResult).spec.name.toUpperCase()}`;
+  if ((lookup as FoundSpecResult).envFilePath && (lookup as FoundSpecResult).range) {
+    const envKey = `COREPACK_DEV_ENGINES_${(lookup as FoundSpecResult).range!.name.toUpperCase()}`;
     const index = content.lastIndexOf(`\n${envKey}=`) + 1;
 
     if (index === 0 && !content.startsWith(`${envKey}=`))
@@ -168,13 +168,13 @@ export async function setLocalPackageManager(cwd: string, info: PreparedPackageM
   };
 }
 
-type FoundSpecResult = {type: `Found`, target: string, spec: Descriptor, range?: Descriptor, envFilePath?: string};
-export type LoadSpecResult =
+type FoundSpecResult<SkipSpecParsing extends boolean = true> = {type: `Found`, target: string, spec: SkipSpecParsing extends true ? undefined : Descriptor, range?: Descriptor, envFilePath?: string};
+export type LoadSpecResult<SkipSpecParsing extends boolean> =
     | {type: `NoProject`, target: string}
     | {type: `NoSpec`, target: string}
-    | FoundSpecResult;
+    | FoundSpecResult<SkipSpecParsing>;
 
-export async function loadSpec(initialCwd: string): Promise<LoadSpecResult> {
+export async function loadSpec<SkipSpecParsing extends boolean = false>(initialCwd: string, skipSpecParsing?: SkipSpecParsing): Promise<LoadSpecResult<SkipSpecParsing>> {
   let nextCwd = initialCwd;
   let currCwd = ``;
 
@@ -258,10 +258,12 @@ export async function loadSpec(initialCwd: string): Promise<LoadSpecResult> {
     type: `Found`,
     target: selection.manifestPath,
     envFilePath,
-    spec: parseSpec(rawPmSpec, path.relative(initialCwd, selection.manifestPath)),
     range: selection.data.devEngines?.packageManager?.version && {
       name: selection.data.devEngines.packageManager.name,
       range: selection.data.devEngines.packageManager.version,
     },
+    spec: skipSpecParsing ?
+      (undefined as SkipSpecParsing extends true ? undefined : never) :
+      parseSpec(rawPmSpec, path.relative(initialCwd, selection.manifestPath)) as SkipSpecParsing extends true ? never : ReturnType<typeof parseSpec>,
   };
 }

tests/Use.test.ts

@@ -144,4 +144,50 @@ describe(`UseCommand`, () => {
       });
     });
   });
+
+  describe(`should not care if packageManager is set to an invalid value`, () => {
+    for (const {description, packageManager} of [
+      {
+        description: `when a version range is given`,
+        packageManager: `yarn@1.x`,
+      },
+      {
+        description: `when only the pm name is given`,
+        packageManager: `yarn`,
+      },
+      {
+        description: `when the version is missing`,
+        packageManager: `yarn@`,
+      },
+      {
+        description: `when the field is not a string`,
+        packageManager: [],
+      },
+    ]) {
+      it(description, async () => {
+        await xfs.mktempPromise(async cwd => {
+          await xfs.writeJsonPromise(ppath.join(cwd, `package.json`), {
+            packageManager,
+            license: `MIT`, // To avoid warning
+          });
+
+          await expect(runCli(cwd, [`use`, `yarn@1.22.4`])).resolves.toMatchObject({
+            exitCode: 0,
+            stderr: ``,
+            stdout: expect.stringMatching(/^Installing yarn@1\.22\.4 in the project\.\.\.\n\nyarn install v1\.22\.4\ninfo No lockfile found\.\n(.*\n)+Done in \d+\.\d+s\.\n$/),
+          });
+
+          await expect(xfs.readJsonPromise(ppath.join(cwd, `package.json`))).resolves.toMatchObject({
+            packageManager: `yarn@1.22.4+sha512.a1833b862fe52169bd6c2a033045a07df5bc6a23595c259e675fed1b2d035ab37abe6ce309720abb6636d68f03615054b6292dc0a70da31c8697fda228b50d18`,
+          });
+
+          await expect(runCli(cwd, [`yarn`, `--version`])).resolves.toMatchObject({
+            exitCode: 0,
+            stdout: `1.22.4\n`,
+            stderr: ``,
+          });
+        });
+      });
+    }
+  });
 });