feat: when strict checking is off, treat like transparent

README.md

@@ -134,8 +134,17 @@ This command will retrieve the given package manager from the specified archive
   manager versions that will be required for the projects you'll run, using
   `corepack hydrate`).
 
-- `COREPACK_ENABLE_STRICT` can be set to `0` to prevent Corepack from checking
+- `COREPACK_ENABLE_STRICT` can be set to `0` to prevent Corepack from throwing error
+  if the package manager does not correspond to the one defined for the current project.
+  This means that if a user is using the package manager specified in the current project,
+  it will use the version specified by the project's `packageManager` field.
+  But if the user is using other package manager different from the one specified
+  for the current project, it will use the system-wide package manager version.
+
+- `COREPACK_ENABLE_PROJECT_SPEC` can be set to `0` to prevent Corepack from checking
   if the package manager corresponds to the one defined for the current project.
+  This means that it will always use the system-wide package manager regardless of
+  what is being specified in the project's `packageManager` field.
 
 - `COREPACK_HOME` can be set in order to define where Corepack should install
   the package managers. By default it is set to `%LOCALAPPDATA%\node\corepack`

sources/specUtils.ts

@@ -44,7 +44,11 @@ export async function findProjectSpec(initialCwd: string, locator: Locator, {tra
   // A locator is a valid descriptor (but not the other way around)
   const fallbackLocator = {name: locator.name, range: locator.reference};
 
-  if (process.env.COREPACK_ENABLE_STRICT === `0`) return fallbackLocator;
+  if (process.env.COREPACK_ENABLE_PROJECT_SPEC === `0`)
+    return fallbackLocator;
+
+  if (process.env.COREPACK_ENABLE_STRICT === `0`)
+    transparent = true;
 
   while (true) {
     const result = await loadSpec(initialCwd);

tests/main.test.ts

@@ -270,8 +270,14 @@ it(`should refuse to run a different package manager within a configured project
     process.env.COREPACK_ENABLE_STRICT = `0`;
 
     try {
+      await expect(runCli(cwd, [`yarn`, `--version`])).resolves.toMatchObject({
+        stdout: `1.0.0\n`,
+        stderr: ``,
+        exitCode: 0,
+      });
       await expect(runCli(cwd, [`pnpm`, `--version`])).resolves.toMatchObject({
         stdout: `${config.definitions.pnpm.default.split(`+`, 1)[0]}\n`,
+        stderr: ``,
         exitCode: 0,
       });
     } finally {
@@ -281,6 +287,31 @@ it(`should refuse to run a different package manager within a configured project
   });
 });
 
+
+it(`should always use fallback version when project spec env is disabled`, async () => {
+  await xfs.mktempPromise(async cwd => {
+    await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {
+      packageManager: `yarn@1.0.0`,
+    });
+    process.env.COREPACK_ENABLE_PROJECT_SPEC = `0`;
+
+    try {
+      await expect(runCli(cwd, [`yarn`, `--version`])).resolves.toMatchObject({
+        stdout: `${config.definitions.yarn.default.split(`+`, 1)[0]}\n`,
+        stderr: ``,
+        exitCode: 0,
+      });
+      await expect(runCli(cwd, [`pnpm`, `--version`])).resolves.toMatchObject({
+        stdout: `${config.definitions.pnpm.default.split(`+`, 1)[0]}\n`,
+        stderr: ``,
+        exitCode: 0,
+      });
+    } finally {
+      delete process.env.COREPACK_ENABLE_PROJECT_SPEC;
+    }
+  });
+});
+
 it(`should allow to call "prepare" with --all to prepare all package managers`, async () => {
   await xfs.mktempPromise(async cwd => {
     await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {