fix: release references to completed stage logics in GraphInterpreter

Motivation:
GraphInterpreter retains strong references to completed stage logics in
the logics array, preventing garbage collection even after stages have
finished. This is especially problematic for long-running fused
interpreters that host subfused shells, where completed initial stages
remain referenced for the lifetime of the actor. Additionally,
Connection objects retain strong references to handler objects
(inHandler/outHandler), further preventing GC of completed stage logics.

Modification:
- afterStageHasRun now scans ALL logics for completed stages instead of
  only checking the single activeStage. This ensures stages that complete
  without being activeStage (e.g., boundary stages calling complete(),
  cascading completions) are properly finalized and released.
- finish() and afterStageHasRun null connection handlers (inHandler/
  outHandler) for finalized stages, breaking handler-to-logic reference
  chains to enable garbage collection.
- toSnapshot handles null logics gracefully with <completed> placeholder
  and uses connection.inOwner.stageId for positional indexing instead of
  identity-based map lookups that fail with NPE on null logics.
- inLogicName/outLogicName debug methods guard against null logics.
- finish() sets logics(i) = null after finalizing each stage.
- Fix GraphStageLogicSpec "not double-terminate" test to save logic
  references before execute() since afterStageHasRun now releases
  completed logics.

Result:
Completed stage logics are properly finalized and released for GC
during normal stream execution (not just in finish()), reducing memory
retention in long-running fused interpreters.

Tests:
- stream-tests/testOnly GraphInterpreterSpec: 13/13 passed (includes 2 new regression tests)
- stream-tests/testOnly GraphStageLogicSpec: 17/17 passed
- stream-tests/testOnly InterpreterSpec+LifecycleInterpreterSpec+InterpreterSupervisionSpec+GraphInterpreterFailureModesSpec: 54/54 passed

References:
None - memory leak fix

Author: He-Pin

.github/workflows/binary-compatibility-checks.yml

@@ -37,7 +37,7 @@ jobs:
       DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: 0
@@ -50,7 +50,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1

.github/workflows/build-test-prValidation.yml

@@ -26,7 +26,7 @@ jobs:
       DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -43,15 +43,15 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Code style check
         run: |-
           cp .jvmopts-ci .jvmopts
           sbt \
           -Dsbt.override.build.repos=false \
           -Dsbt.log.noformat=false \
-          checkCodeStyle
+          javafmtCheckAll
   pull-request-validation:
     name: Check / Tests
     runs-on: ubuntu-22.04
@@ -62,7 +62,7 @@ jobs:
         scalaVersion: ["2.13.x", "3.3.x"]
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -76,7 +76,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -126,7 +126,7 @@ jobs:
           - cluster/test distributed-data/test cluster-tools/test cluster-metrics/test
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -140,7 +140,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -164,13 +164,13 @@ jobs:
           clean ${{ matrix.command }}
           
   jdk-21-extra-tests:
-    name: Java 21 Extra Tests
+    name: Java 21 Extra Tests (including all tests that need Java 9+)
     runs-on: ubuntu-22.04
     env:
       DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -184,15 +184,15 @@ jobs:
           java-version: 21
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
 
       - name: Enable jvm-opts
         run: cp .jvmopts-ci .jvmopts
 
-      - name: sbt TestJdk21/test
+      - name: sbt TestJdk9/test
         run: |-
           sbt \
           -Dpekko.mima.enabled=false \
@@ -206,4 +206,4 @@ jobs:
           -Dsbt.log.noformat=false \
           -Dpekko.log.timestamps=true \
           -Dio.netty.leakDetection.level=PARANOID \
-          TestJdk21/test
+          TestJdk9/test        

.github/workflows/dependency-graph.yml

@@ -33,12 +33,12 @@ jobs:
       # to submit dependencies
       contents: write
     steps:
-      - uses: actions/checkout@v6.0.3
+      - uses: actions/checkout@v6.0.2
         with:
           persist-credentials: false
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
-      - uses: scalacenter/sbt-dependency-submission@d84eef4c09e633bcf5f113bcad7fd5e9af1baee9 # v3.1.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
+      - uses: scalacenter/sbt-dependency-submission@1cc96a7038ea2b014c200c1dae3a0cc92293b91d # v3.1.1
         with:
-          configs-ignore: provided optional test TestJdk21 compile-internal runtime-internal pr-validation multi-jvm scala-tool scala-doc-tool
+          configs-ignore: provided optional test TestJdk9 compile-internal runtime-internal pr-validation multi-jvm scala-tool scala-doc-tool
           modules-ignore: pekko-bench-jmh_2.13 pekko-docs_2.13 pekko-bench-jmh_3 pekko-docs_3

.github/workflows/format.yml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout current branch (full)
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           persist-credentials: false

.github/workflows/generate-doc-check.yml

@@ -30,7 +30,7 @@ jobs:
     if: github.repository == 'apache/pekko'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -43,7 +43,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -55,4 +55,4 @@ jobs:
       - name: Compile testClass&docs for all Scala versions
         env:
           DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
-        run: sbt ";+TestJdk21 / compile ; +compile:doc"
+        run: sbt ";+TestJdk9 / compile ; +compile:doc"

.github/workflows/headers.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           persist-credentials: false
 
@@ -39,7 +39,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1

.github/workflows/link-validator.yml

@@ -21,7 +21,7 @@ jobs:
     if: github.repository == 'apache/pekko'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           persist-credentials: false
 
@@ -38,7 +38,7 @@ jobs:
           java-version: 17
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1

.github/workflows/nightly-1.0-builds.yml

@@ -21,7 +21,7 @@ jobs:
     if: github.repository == 'apache/pekko'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -35,7 +35,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -75,7 +75,7 @@ jobs:
           - cluster-typed/test cluster-sharding-typed/test
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -90,7 +90,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -127,7 +127,7 @@ jobs:
         javaVersion: [8, 11, 17, 21]
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -141,7 +141,7 @@ jobs:
           java-version: ${{ matrix.javaVersion }}
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1

.github/workflows/nightly-1.1-builds.yml

@@ -21,7 +21,7 @@ jobs:
     if: github.repository == 'apache/pekko'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -35,7 +35,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -76,7 +76,7 @@ jobs:
           - cluster-typed/test cluster-sharding-typed/test
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -91,7 +91,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -129,7 +129,7 @@ jobs:
         javaVersion: [8, 11, 17, 21]
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -143,7 +143,7 @@ jobs:
           java-version: ${{ matrix.javaVersion }}
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1

.github/workflows/nightly-1.2-builds.yml

@@ -21,7 +21,7 @@ jobs:
     if: github.repository == 'apache/pekko'
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -35,7 +35,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -76,7 +76,7 @@ jobs:
           - cluster-typed/test cluster-sharding-typed/test
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           # we don't know what commit the last tag was it's safer to get entire repo so previousStableVersion resolves
           fetch-depth: 0
@@ -91,7 +91,7 @@ jobs:
           java-version: 11
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1
@@ -129,7 +129,7 @@ jobs:
         javaVersion: [8, 11, 17, 21]
     steps:
       - name: Checkout
-        uses: actions/checkout@v6.0.3
+        uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           fetch-tags: true
@@ -143,7 +143,7 @@ jobs:
           java-version: ${{ matrix.javaVersion }}
 
       - name: Install sbt
-        uses: sbt/setup-sbt@af116cce31c00823d3903ce687f9cda3a4f19f1b # v1.2.1
+        uses: sbt/setup-sbt@2e222825582620cc38d2a54e674f3c01b7c14f5d # v1.1.24
 
       - name: Cache Coursier cache
         uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d # 8.1.1