Merge b8ecc20d6f into 65d868f8d4

* update documentation for lockfile

* Update adavance usage in README.md

* Documentation update

* Update lockfile documenation

* fix coplilot suggestion

README.md

@@ -123,7 +123,7 @@ steps:
 - run: npm test
 ```
 
-The `node-version` input is optional. If not supplied, the node version from PATH will be used. However, it is recommended to always specify Node.js version and don't rely on the system one.
+The `node-version` input is optional. If not supplied, the node version from PATH will be used. However, it is recommended to always specify Node.js version and not rely on the system one.
 
 The action will first check the local cache for a semver match. If unable to find a specific version in the cache, the action will attempt to download a version of Node.js. It will pull LTS versions from [node-versions releases](https://github.com/actions/node-versions/releases) and on miss or failure will fall back to the previous behavior of downloading directly from [node dist](https://nodejs.org/dist/).
 
@@ -148,7 +148,7 @@ Since it will not be cached always, there is possibility of hitting rate limit w
 
 ### Checking in lockfiles
 
-It's **always** recommended to commit the lockfile of your package manager for security and performance reasons. For more information consult the "Working with lockfiles" section of the [Advanced usage](docs/advanced-usage.md#working-with-lockfiles) guide.
+It's **strongly recommended** to commit the lockfile of your package manager for security and performance reasons. For more information consult the "Working with lockfiles" section of the [Advanced usage](docs/advanced-usage.md#working-with-lockfiles) guide.
 
 ## Caching global packages data
 
@@ -249,6 +249,7 @@ If the runner is not able to access github.com, any Nodejs versions requested du
  - [Publishing to npmjs and GPR with npm](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-npm)
  - [Publishing to npmjs and GPR with yarn](docs/advanced-usage.md#publish-to-npmjs-and-gpr-with-yarn)
  - [Using private packages](docs/advanced-usage.md#use-private-packages)
+ - [Using private mirror](docs/advanced-usage.md#use-private-mirror)
 
 ## Recommended permissions
 

docs/advanced-usage.md

@@ -1,6 +1,6 @@
 ## Working with lockfiles
 
-All supported package managers recommend that you **always** commit the lockfile, although implementations vary doing so generally provides the following benefits:
+Most supported package managers recommend that you **always** commit the lockfile, although implementations vary doing so generally provides the following benefits:
 
 - Enables faster installation for CI and production environments, due to being able to skip package resolution.
 - Describes a single representation of a dependency tree such that teammates, deployments, and continuous integration are guaranteed to install exactly the same dependencies.
@@ -35,6 +35,25 @@ Ensure that `pnpm-lock.yaml` is always committed, when on CI pass `--frozen-lock
 - [Working with Git - Lockfiles](https://pnpm.io/git#lockfiles)
 - [Documentation of `--frozen-lockfile` option](https://pnpm.io/cli/install#--frozen-lockfile)
 
+### Running without a lockfile
+
+If you choose not to use a lockfile, you must ensure that **caching is disabled**. The `cache` feature relies on the lockfile to generate a unique key for the cache entry.
+
+To run without a lockfile:
+1. Do not set the `cache` input.
+2. If your `package.json` contains a `packageManager` field set to npm (or devEngines.packageManager), automatic caching is enabled by default. Override this by setting `package-manager-cache: false`.
+
+```yaml
+steps:
+- uses: actions/checkout@v6
+- uses: actions/setup-node@v6
+  with:
+    node-version: '24'
+    package-manager-cache: false # Explicitly disable caching if you don't have a lockfile
+- run: npm install
+- run: npm test
+```
+
 ## Check latest version
 
 The `check-latest` flag defaults to `false`. When set to `false`, the action will first check the local cache for a semver match. If unable to find a specific version in the cache, the action will attempt to download a version of Node.js. It will pull LTS versions from [node-versions releases](https://github.com/actions/node-versions/releases) and on miss or failure will fall back to the previous behavior of downloading directly from [node dist](https://nodejs.org/dist/). Use the default or set `check-latest` to `false` if you prefer stability and if you want to ensure a specific version of Node.js is always used.