Enable wrapper-validation by default in setup-gradle (#318)

.github/actions/init-integ-test/action.yml

@@ -9,6 +9,11 @@ runs:
         distribution: 'temurin'
         java-version: 11
 
+    - name: Configure environment
+      shell: bash
+      run: |
+        echo "ALLOWED_GRADLE_WRAPPER_CHECKSUMS=e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855" >> "$GITHUB_ENV"
+
     # Downloads a 'dist' directory artifact that was uploaded in an earlier 'build-dist' step
     - name: Download dist
       if: ${{ env.SKIP_DIST != 'true' && !env.ACT }}

.github/workflows/integ-test-wrapper-validation.yml

@@ -29,8 +29,8 @@ jobs:
     - name: Run wrapper-validation-action
       id: setup-gradle
       uses: ./setup-gradle
-      with:
-        validate-wrappers: true
+      env:
+        ALLOWED_GRADLE_WRAPPER_CHECKSUMS: ''
       continue-on-error: true
 
     - name: Check failure

dependency-submission/action.yml

@@ -172,6 +172,21 @@ inputs:
     description: The Develocity short-lived access tokens expiry in hours. Default is 2 hours.
     required: false
 
+  # Wrapper validation configuration
+  validate-wrappers:
+    description: |
+      When 'true' the action will automatically validate all wrapper jars found in the repository.
+      If the wrapper checksums are not valid, the action will fail.
+    required: false
+    default: false
+
+  allow-snapshot-wrappers:
+    description: |
+      When 'true', wrapper validation will include the checksums of snapshot wrapper jars. 
+      Use this if you are running with nightly or snapshot versions of the Gradle wrapper.
+    required: false
+    default: false
+
   # DEPRECATED ACTION INPUTS
 
   # EXPERIMENTAL ACTION INPUTS

docs/setup-gradle.md

@@ -515,14 +515,30 @@ Since Gradle applies init scripts in alphabetical order, one way to ensure this
 
 ## Gradle Wrapper validation
 
-Instead of using the [wrapper-validation action](./wrapper-validation.md) separately, you can enable
-wrapper validation directly in your Setup Gradle step.
+By default, this action will perform the same wrapper validation as is performed by the dedicated 
+[wrapper-validation action](./wrapper-validation.md). 
+This means that invalid wrapper jars will be automatically detected when using `setup-gradle`. 
+
+If you do not want wrapper-validation to occur automatically, you can disable it:
+
+```yaml
+    - name: Setup Gradle
+      uses: gradle/actions/setup-gradle@v3
+      with:
+        validate-wrappers: false
+```
+
+If your repository uses snapshot versions of the Gradle wrapper, such as nightly builds, then you'll need to 
+explicitly allow snapshot wrappers in wrapper validation.
+These are not allowed by default.
+
 
 ```yaml
     - name: Setup Gradle
       uses: gradle/actions/setup-gradle@v3
       with:
         validate-wrappers: true
+        allow-snapshot-wrappers: true
 ```
 
 If you need more advanced configuration, then you're advised to continue using a separate workflow step

docs/wrapper-validation.md

@@ -4,6 +4,9 @@ This action validates the checksums of _all_ [Gradle Wrapper](https://docs.gradl
 
 The action should be run in the root of the repository, as it will recursively search for any files named `gradle-wrapper.jar`.
 
+The `setup-gradle` action will perform wrapper validation on each execution. If you are using `setup-gradle` in your
+workflows, it is unlikely that you will need to use this action.
+
 ## The Gradle Wrapper Problem in Open Source
 
 The `gradle-wrapper.jar` is a binary blob of executable code that is checked into nearly
@@ -90,18 +93,22 @@ We recommend the message commit contents of:
 
 From there, you can easily follow the rest of the prompts to create a Pull Request against the project.
 
-## Reporting Failures
+## Validation Failures
 
-If this GitHub action fails because a `gradle-wrapper.jar` doesn't match one of our published SHA-256 checksums,
-we highly recommend that you reach out to us at [security@gradle.com](mailto:security@gradle.com).
+A wrapper jar can fail validation for a few reasons:
+1. The wrapper is from a snapshot build of Gradle (nightly or release nightly) and you have not set `allow-snapshots`
+   or `allow-snapshot-wrappers` to `true`.
+2. The wrapper jar is from a version of Gradle with an unverifiable wrapper jar (see below).
+3. The wrapper jar was not published by Gradle, and could be compromised.
 
-**Note:** `gradle-wrapper.jar` generated by Gradle 3.3 to 4.0 are not verifiable because those files were dynamically generated by Gradle in a non-reproducible way. It's not possible to verify the `gradle-wrapper.jar` for those versions are legitimate using a hash comparison. You should try to determine if the `gradle-wrapper.jar` was generated by one of these versions before running the build.
+If this GitHub action fails because a `gradle-wrapper.jar` was not published by Gradle,
+we highly recommend that you reach out to us at [security@gradle.com](mailto:security@gradle.com).
 
-If the Gradle version in `gradle-wrapper.properties` is out of this range, you may need to regenerate the `gradle-wrapper.jar` by running `./gradlew wrapper`. If you need to use a version of Gradle between 3.3 and 4.0, you can use a newer version of Gradle to generate the `gradle-wrapper.jar`.
+#### Unverifiable Wrapper Jars
+Wrapper Jars generated by Gradle versions `3.3` to `4.0` are not verifiable because those files were dynamically generated by Gradle in a non-reproducible way. It's not possible to verify the `gradle-wrapper.jar` for those versions are legitimate using a hash comparison. If you have a validation failure, you should try to determine if the `gradle-wrapper.jar` was generated by one of these versions before running the build.
 
-If you're curious and want to explore what the differences are between the `gradle-wrapper.jar` in your possession
-and one of our valid release, you can compare them using this online utility: [diffoscope](https://try.diffoscope.org/).
-Regardless of what you find, we still kindly request that you reach out to us and let us know.
+- If the Gradle version in `gradle-wrapper.properties` is outside of this range, you can regenerate the `gradle-wrapper.jar` by running `./gradlew wrapper`. This will generate a new, verifiable wrapper jar.
+- If you need to run your build with a version of Gradle between 3.3 and 4.0, you can use a newer version of Gradle to generate the `gradle-wrapper.jar`.
 
 ## Resources
 

setup-gradle/action.yml

@@ -190,9 +190,16 @@ inputs:
   # Wrapper validation configuration
   validate-wrappers:
     description: |
-      When 'true', the action will perform the 'wrapper-validation' action automatically.
+      When 'true' (the default) the action will automatically validate all wrapper jars found in the repository.
       If the wrapper checksums are not valid, the action will fail.
     required: false
+    default: true
+
+  allow-snapshot-wrappers:
+    description: |
+      When 'true', wrapper validation will include the checksums of snapshot wrapper jars. 
+      Use this if you are running with nightly or snapshot versions of the Gradle wrapper.
+    required: false
     default: false
 
   # DEPRECATED ACTION INPUTS