From 7de151f2cbda704ed8db581f6b37d2b2020f16e5 Mon Sep 17 00:00:00 2001
From: RanVaknin <50976344+RanVaknin@users.noreply.github.com>
Date: Tue, 14 Oct 2025 15:49:58 -0700
Subject: [PATCH 1/5] Add mixed version compatibility detection workflow

- Detects changes to base classes (AwsRequest, AwsResponse, SdkPojo, etc.)
- Requires manual review via 'mixed-version-compatibility-reviewed' label
- Prevents merge until team approves compatibility impact
---
 .../mixed-version-compatibility-review.yml    | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 .github/workflows/mixed-version-compatibility-review.yml

diff --git a/.github/workflows/mixed-version-compatibility-review.yml b/.github/workflows/mixed-version-compatibility-review.yml
new file mode 100644
index 000000000000..c2426d083f6e
--- /dev/null
+++ b/.github/workflows/mixed-version-compatibility-review.yml
@@ -0,0 +1,87 @@
+name: Mixed Version Compatibility Review
+
+permissions:
+  contents: read
+  pull-requests: read
+
+on:
+  merge_group:
+  pull_request:
+    types: [ opened, synchronize, reopened, labeled, unlabeled ]
+    branches:
+      - master
+
+jobs:
+  mixed-version-compatibility-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      
+      - name: Check for mixed version compatibility risks
+        id: compatibility-check
+        run: |
+          git fetch origin ${{ github.base_ref }} --depth 1
+          
+          # Define the specific base class files that are risky for mixed versions
+          BASE_CLASS_FILES="core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsRequest.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsResponse.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsResponseMetadata.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/exception/AwsServiceException.java
+          core/sdk-core/src/main/java/software/amazon/awssdk/core/SdkPojo.java"
+          
+          # Check if any of the base class files were modified
+          CHANGED_BASE_FILES=$(git diff --name-only remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES || true)
+          
+          if [ -z "$CHANGED_BASE_FILES" ]; then
+            echo "No base class changes detected."
+            echo "has_risk=false" >> $GITHUB_OUTPUT
+            exit 0
+          fi
+          
+          echo "Base class changes detected in:"
+          echo "$CHANGED_BASE_FILES"
+          
+          # Look for new public methods in the changed base class files
+          NEW_METHODS=$(git diff remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES | grep '^+.*public.*(' || true)
+          
+          if [ -n "$NEW_METHODS" ]; then
+            echo "::warning::New public methods detected in base classes:"
+            echo "$NEW_METHODS" | while read line; do
+              echo "::warning::$line"
+            done
+            echo "has_risk=true" >> $GITHUB_OUTPUT
+            echo "risk_type=new_methods" >> $GITHUB_OUTPUT
+          else
+            echo "::warning::Base class files modified but no new public methods detected"
+            echo "has_risk=true" >> $GITHUB_OUTPUT  
+            echo "risk_type=other_changes" >> $GITHUB_OUTPUT
+          fi
+      
+      - name: Fail if compatibility risks found without approval
+        if: ${{ steps.compatibility-check.outputs.has_risk == 'true' && !contains(github.event.pull_request.labels.*.name, 'mixed-version-compatibility-reviewed') }}
+        run: |
+          echo "::error::Mixed version compatibility risk detected!"
+          echo "::error::Changes were made to base classes that generated service code implements:"
+          echo "::error::- AwsRequest, AwsResponse, AwsResponseMetadata, AwsServiceException, SdkPojo"
+          echo "::error::"
+          echo "::error::This may break customers using mixed SDK versions if:"
+          echo "::error::- New methods are added with UnsupportedOperationException defaults"
+          echo "::error::- Core behavior changes invoke existing methods in new ways"
+          echo "::error::- Interface contracts change in subtle ways"
+          echo "::error::"
+          echo "::error::Please review with the team for mixed version impact and add"
+          echo "::error::'mixed-version-compatibility-reviewed' label after approval."
+          echo "::error::"
+          echo "::error::If this introduces compatibility issues, consider:"
+          echo "::error::- Bumping minor version"
+          echo "::error::- Documenting compatibility impact in release notes"
+          echo "::error::- Ensuring older service modules can handle the changes"
+          exit 1
+      
+      - name: Success message when approved
+        if: ${{ steps.compatibility-check.outputs.has_risk == 'true' && contains(github.event.pull_request.labels.*.name, 'mixed-version-compatibility-reviewed') }}
+        run: |
+          echo "✅ Mixed version compatibility risk detected but approved for merge"
+          echo "Base class changes have been reviewed and approved by the team"
\ No newline at end of file

From b4cf90620cba74468882cb72f65cd03005d50495 Mon Sep 17 00:00:00 2001
From: RanVaknin <50976344+RanVaknin@users.noreply.github.com>
Date: Tue, 14 Oct 2025 16:12:33 -0700
Subject: [PATCH 2/5] Improve mixed version detection: filter false positives

- Filter out comments containing 'public.*(' patterns
- Filter out string literals with 'public.*(' patterns
- Filter out javadoc examples with 'public.*(' patterns
- Reduces noise while maintaining detection accuracy
---
 .github/workflows/mixed-version-compatibility-review.yml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/mixed-version-compatibility-review.yml b/.github/workflows/mixed-version-compatibility-review.yml
index c2426d083f6e..936b1c814266 100644
--- a/.github/workflows/mixed-version-compatibility-review.yml
+++ b/.github/workflows/mixed-version-compatibility-review.yml
@@ -44,7 +44,12 @@ jobs:
           echo "$CHANGED_BASE_FILES"
           
           # Look for new public methods in the changed base class files
-          NEW_METHODS=$(git diff remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES | grep '^+.*public.*(' || true)
+          # Filter out obvious false positives: comments, string literals, javadoc
+          NEW_METHODS=$(git diff remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES | \
+            grep '^+.*public.*(' | \
+            grep -v '^+[[:space:]]*//.*public.*(' | \
+            grep -v '^+.*".*public.*(' | \
+            grep -v '^+[[:space:]]*\*.*public.*(' || true)
           
           if [ -n "$NEW_METHODS" ]; then
             echo "::warning::New public methods detected in base classes:"

From 47d0582730b241e25d8aa0dd9150cb5f246bf50c Mon Sep 17 00:00:00 2001
From: RanVaknin <50976344+RanVaknin@users.noreply.github.com>
Date: Tue, 14 Oct 2025 16:19:44 -0700
Subject: [PATCH 3/5] Fix false positive filtering for block comments

Add filtering for block comments that start with /*
This should catch patterns like: /* Example usage: public void method() */
---
 .github/workflows/mixed-version-compatibility-review.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/mixed-version-compatibility-review.yml b/.github/workflows/mixed-version-compatibility-review.yml
index 936b1c814266..d57fd6be08eb 100644
--- a/.github/workflows/mixed-version-compatibility-review.yml
+++ b/.github/workflows/mixed-version-compatibility-review.yml
@@ -49,7 +49,8 @@ jobs:
             grep '^+.*public.*(' | \
             grep -v '^+[[:space:]]*//.*public.*(' | \
             grep -v '^+.*".*public.*(' | \
-            grep -v '^+[[:space:]]*\*.*public.*(' || true)
+            grep -v '^+[[:space:]]*\*.*public.*(' | \
+            grep -v '^+[[:space:]]*/\*.*public.*(' || true)
           
           if [ -n "$NEW_METHODS" ]; then
             echo "::warning::New public methods detected in base classes:"

From 74eeb2a33d055c88ee7f6b28508d90547ee995c6 Mon Sep 17 00:00:00 2001
From: RanVaknin <50976344+RanVaknin@users.noreply.github.com>
Date: Wed, 15 Oct 2025 14:48:25 -0700
Subject: [PATCH 4/5] Address feedback: show only changed class names in error
 message

- Extract class names from actually changed files, not all possible files
- Makes error message dynamic and specific to detected changes
- Addresses maintainability concern from code review
---
 .../mixed-version-compatibility-review.yml          | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/mixed-version-compatibility-review.yml b/.github/workflows/mixed-version-compatibility-review.yml
index d57fd6be08eb..f5f83eac66d8 100644
--- a/.github/workflows/mixed-version-compatibility-review.yml
+++ b/.github/workflows/mixed-version-compatibility-review.yml
@@ -68,9 +68,20 @@ jobs:
       - name: Fail if compatibility risks found without approval
         if: ${{ steps.compatibility-check.outputs.has_risk == 'true' && !contains(github.event.pull_request.labels.*.name, 'mixed-version-compatibility-reviewed') }}
         run: |
+          # Define the base class files
+          BASE_CLASS_FILES="core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsRequest.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsResponse.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/AwsResponseMetadata.java
+          core/aws-core/src/main/java/software/amazon/awssdk/awscore/exception/AwsServiceException.java
+          core/sdk-core/src/main/java/software/amazon/awssdk/core/SdkPojo.java"
+          
+          # Extract class names from the actually changed files
+          CHANGED_BASE_FILES=$(git diff --name-only remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES || true)
+          CHANGED_CLASS_NAMES=$(echo "$CHANGED_BASE_FILES" | sed 's|.*/||' | sed 's|\.java||' | paste -sd ',' - | sed 's/,/, /g')
+          
           echo "::error::Mixed version compatibility risk detected!"
           echo "::error::Changes were made to base classes that generated service code implements:"
-          echo "::error::- AwsRequest, AwsResponse, AwsResponseMetadata, AwsServiceException, SdkPojo"
+          echo "::error::- $CHANGED_CLASS_NAMES"
           echo "::error::"
           echo "::error::This may break customers using mixed SDK versions if:"
           echo "::error::- New methods are added with UnsupportedOperationException defaults"

From 915f93b9cc6e42ec84f7ba57393ef89ebecdb8a7 Mon Sep 17 00:00:00 2001
From: RanVaknin <50976344+RanVaknin@users.noreply.github.com>
Date: Wed, 15 Oct 2025 21:07:21 -0700
Subject: [PATCH 5/5] Add comments, expand exclusion of patterns

---
 .../workflows/mixed-version-compatibility-review.yml   | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/mixed-version-compatibility-review.yml b/.github/workflows/mixed-version-compatibility-review.yml
index f5f83eac66d8..548d4b530737 100644
--- a/.github/workflows/mixed-version-compatibility-review.yml
+++ b/.github/workflows/mixed-version-compatibility-review.yml
@@ -46,11 +46,11 @@ jobs:
           # Look for new public methods in the changed base class files
           # Filter out obvious false positives: comments, string literals, javadoc
           NEW_METHODS=$(git diff remotes/origin/${{ github.base_ref }} -- $BASE_CLASS_FILES | \
-            grep '^+.*public.*(' | \
-            grep -v '^+[[:space:]]*//.*public.*(' | \
-            grep -v '^+.*".*public.*(' | \
-            grep -v '^+[[:space:]]*\*.*public.*(' | \
-            grep -v '^+[[:space:]]*/\*.*public.*(' || true)
+          
+          grep '^+.*public.*(' | \                # Find lines with new public methods
+          grep -v '^+[[:space:]]*//.*' | \        # Line comments  
+          grep -v '^+[[:space:]]*\*.*' | \        # Javadoc lines
+          grep -v '^+[[:space:]]*/\*.*' || true   # Block comments
           
           if [ -n "$NEW_METHODS" ]; then
             echo "::warning::New public methods detected in base classes:"