Update README for v2

README.md

@@ -2,9 +2,13 @@
 
 This GitHub Action can be used to execute a Gradle build on any platform supported by GitHub Actions.
 
+**Note:** The following documentation is for `gradle/gradle-build-action@v2`, currently in Beta release.
+You can view the documentation for the latest stable release (v1.5.1) [on the GitHub Marketplace](https://github.com/marketplace/actions/gradle-build-action?version=v1.5.1). 
+
 ## Usage
 
-The following workflow will run `./gradlew build` using the wrapper from the repository on ubuntu, macos and windows. The only prerequisite is to have Java installed: you define the version of Java you need to run the build using the `actions/setup-java` action.
+The following workflow will run `./gradlew build` on ubuntu, macos and windows. 
+The only prerequisite is to have Java installed: you define the version of Java you need to run the build using the `actions/setup-java` action.
 
 ```yaml
 # .github/workflows/gradle-build-pr.yml
@@ -21,12 +25,26 @@ jobs:
     - uses: actions/setup-java@v1
       with:
         java-version: 11
-    - uses: gradle/gradle-build-action@v1
+    - uses: gradle/gradle-build-action@v2
       with:
         arguments: build
 ```
 
-## Gradle arguments
+It is possible to configure multiple Gradle executions to run sequentially in the same job. 
+Each invocation will start its run with the filesystem state remaining from the previous execution.
+
+```yaml
+- uses: gradle/gradle-build-action@v2
+  with:
+    arguments: assemble
+- uses: gradle/gradle-build-action@v2
+  with:
+    arguments: check
+```
+
+## Gradle Execution
+
+### Command-line arguments
 
 The `arguments` input can used to pass arbitrary arguments to the `gradle` command line.
 
@@ -42,42 +60,47 @@ arguments: build -DsystemProperty=bar
 
 See `gradle --help` for more information.
 
-If you need to pass environment variables, simply use the GitHub Actions workflow syntax:
+If you need to pass environment variables, use the GitHub Actions workflow syntax:
 
 ```yaml
-- uses: gradle/gradle-build-action@v1
+- uses: gradle/gradle-build-action@v2
   env:
     CI: true
+  with:
+    arguments: build
 ```
 
-## Run a build from a different directory
+### Gradle build located in a subdirectory
+
+By default, the action will execute Gradle in the root directory of your project. 
+Use the `build-root-directory` input to target a Gradle build in a subdirectory.
 
 ```yaml
-- uses: gradle/gradle-build-action@v1
+- uses: gradle/gradle-build-action@v2
   with:
     build-root-directory: some/subdirectory
 ```
 
-## Use a specific `gradle` executable
+### Using a specific Gradle executable
+
+The action will first look for a Gradle wrapper script in the root directory of your project. 
+If not found, `gradle` will be executed from the PATH.
+Use the `gradle-executable` input to execute using a specific Gradle installation.
 
 ```yaml
- - uses: gradle/gradle-build-action@v1
+ - uses: gradle/gradle-build-action@v2
    with:
-     gradle-executable: path/to/gradle
+     gradle-executable: /path/to/installed/gradle
 ```
 
-## Use a Gradle wrapper from a different directory
+This mechanism can also be used to target a Gradle wrapper script that is located in a non-default location.
+
+### Download, install and use a specific Gradle version
+
+The `gradle-build-action` is able to download and install a specific Gradle version to execute.
 
 ```yaml
- - uses: gradle/gradle-build-action@v1
+ - uses: gradle/gradle-build-action@v2
-   with:
-     gradle-executable: path/to/gradlew
- ```
-
-## Setup and use a declared Gradle version
-
-```yaml
- - uses: gradle/gradle-build-action@v1
    with:
      gradle-version: 6.5
 ```
@@ -94,7 +117,7 @@ Moreover, you can use the following aliases:
 | `nightly`           | The latest [nightly](https://gradle.org/nightly/), fails if none. |
 | `release-nightly`   | The latest [release nightly](https://gradle.org/release-nightly/), fails if none.      |
 
-This can be handy to, for example, automatically test your build with the next Gradle version once a release candidate is out:
+This can be handy to automatically verify your build works with the latest release candidate of Gradle:
 
 ```yaml
 # .github/workflows/test-gradle-rc.yml
@@ -110,7 +133,7 @@ jobs:
     - uses: actions/setup-java@v1
       with:
         java-version: 11
-    - uses: gradle/gradle-build-action@v1
+    - uses: gradle/gradle-build-action@v2
       with:
         gradle-version: release-candidate
         arguments: build --dry-run # just test build configuration
@@ -118,28 +141,34 @@ jobs:
 
 ## Caching
 
-This action provides 3 levels of caching to help speed up your GitHub Actions:
-
-- `distributions` caches any distributions downloaded to satisfy a `gradle-version` parameter ;
-- `gradle-user-home` caches downloaded dependencies, wrapper distributions, and other stuff from the Gradle User home directory ;
-- `project-dot-gradle` caches stored [configuration-cache](https://docs.gradle.org/nightly/userguide/configuration_cache.html) state, saving time configuring the build.
-
-Each of these are enabled by default. To save caching space, you can disable any of them as follows:
-
-```yaml
-distributions-cache-enabled: true
-gradle-user-home-cache-enabled: true
-project-dot-gradle-cache-enabled: true
-```
-
-The distributions cache uses a cache key that is unique to the downloaded distribution. This will not change over time.
-
-The `gradle-user-home` and `project-dot-gradle` caches compute a cache key based on the current commit and the Gradle invocation.
-As such, these are likely to change on each subsequent run of GitHub actions, allowing the most recent state to always be available in the GitHub actions cache.
-
 By default, this action aims to cache any and all reusable state that may be speed up a subsequent build invocation. 
 
-At this time it is not possible to fine-tune this caching. If you have a legitimate use case for fine-grained caching or restricting which files are cached, please raise an issue.
+The state that is cached includes:
+- Any distributions downloaded to satisfy a `gradle-version` parameter ;
+- A subset of the Gradle User Home directory, including downloaded dependencies, wrapper distributions, and the local build cache ;
+- Any [configuration-cache](https://docs.gradle.org/nightly/userguide/configuration_cache.html) data stored in the project `.gradle` directory.
+
+To reduce the space required for caching, this action makes a best effort to reduce duplication in cache entries.
+
+Caching is enabled by default. You can disable caching for the action as follows:
+```yaml
+cache-disabled: true
+```
+
+At this time it is not possible to fine-tune the caching performed by this action. 
+If you have a legitimate use case for fine-grained caching or restricting which files are cached, please raise an issue.
+
+### Cache keys
+
+For cached distributions, the cache key is unique to the downloaded distribution. This will not change over time.
+
+The state of the Gradle User Home and configuration-cache are highly dependent on the Gradle execution, so the cache key is composed of the current commit hash and the GitHub actions job id.
+As such, the cache key is likely to change on each subsequent run of GitHub actions. 
+This allows the most recent state to always be available in the GitHub actions cache.
+
+To reduce duplication between cache entries, certain artifacts are cached independently based on their identity.
+Artifacts that are cached independently include downloaded dependencies, downloaded wrapper distributions and generated Gradle API jars.
+For example, this means that all jobs executing a particular version of the Gradle wrapper will share common entries for wrapper distributions and for generated Gradle API jars.
 
 ### Using the caches read-only
 
@@ -147,21 +176,19 @@ Cache storage space is limited for GitHub actions, and writing new cache entries
 In some circumstances, it makes sense for a Gradle invocation to read any existing cache entries but not to write changes back.
 For example, you may want to write cache entries for builds on your `main` branch, but not for any PR build invocations.
 
-You can enable read-only caching for any of the caches asfollows:
+You can enable read-only caching for any of the caches as follows:
 
 ```yaml
-distributions-cache-enabled: read-only
+cache-read-only: true
-gradle-user-home-cache-enabled: read-only
-project-dot-gradle-cache-enabled: read-only
 ```
 
 ## Build scans
 
-If your build publishes a [build scan](https://gradle.com/build-scans/) the `gradle-build-action` action will emit the link to the published build scan as an output named `build-scan-url`.
+If your build publishes a [build scan](https://gradle.com/build-scans/) the `gradle-build-action` action will:
+- Add a notice with the link to the GitHub Actions user interface
+- Emit the link to the published build scan as an output named `build-scan-url`.
 
-You can then use that link in subsequent actions of your workflow.
+You can then use that link in subsequent actions of your workflow. For example:
-
-For example:
 
 ```yaml
 # .github/workflows/gradle-build-pr.yml
@@ -169,19 +196,16 @@ name: Run Gradle on PRs
 on: pull_request
 jobs:
   gradle:
-    strategy:
+    runs-on: ubuntu-latest
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-    runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
         java-version: 11
-    - uses: gradle/gradle-build-action@v1
+    - uses: gradle/gradle-build-action@v2
+      id: gradle
       with:
         arguments: build
-      id: gradle
     - name: "Comment build scan url"
       uses: actions/github-script@v3
       if: github.event_name == 'pull_request' && failure()