Mark build-result files as processed to avoid double-dipping

On long-lived machines, it's possible that the `.build-results` directory isn't
cleared between invocations. This will result in the job summary including
results from previous jobs.

By marking each build-results file as 'processed', we can avoid this scenario.

.github/workflows/demo-job-summary.yml

@@ -16,6 +16,10 @@ jobs:
         npm install
         npm run build
       working-directory: sources
+    - uses: actions/setup-java@v4
+      with:
+        distribution: 'temurin'
+        java-version: '11'
     - name: Setup Gradle
       uses: ./setup-gradle
     - name: Build kotlin-dsl project

sources/src/build-results.ts

@@ -13,15 +13,38 @@ export interface BuildResult {
 }
 
 export function loadBuildResults(): BuildResult[] {
+    return getUnprocessedResults().map(filePath => {
+        const content = fs.readFileSync(filePath, 'utf8')
+        return JSON.parse(content) as BuildResult
+    })
+}
+
+export function markBuildResultsProcessed(): void {
+    getUnprocessedResults().forEach(markProcessed)
+}
+
+function getUnprocessedResults(): string[] {
     const buildResultsDir = path.resolve(process.env['RUNNER_TEMP']!, '.build-results')
     if (!fs.existsSync(buildResultsDir)) {
         return []
     }
 
-    return fs.readdirSync(buildResultsDir).map(file => {
-        // Every file in the .build-results dir should be a BuildResults JSON
-        const filePath = path.join(buildResultsDir, file)
-        const content = fs.readFileSync(filePath, 'utf8')
-        return JSON.parse(content) as BuildResult
-    })
+    return fs
+        .readdirSync(buildResultsDir)
+        .map(file => {
+            return path.resolve(buildResultsDir, file)
+        })
+        .filter(filePath => {
+            return path.extname(filePath) === '.json' && !isProcessed(filePath)
+        })
+}
+
+function isProcessed(resultFile: string): boolean {
+    const markerFile = `${resultFile}.processed`
+    return fs.existsSync(markerFile)
+}
+
+function markProcessed(resultFile: string): void {
+    const markerFile = `${resultFile}.processed`
+    fs.writeFileSync(markerFile, '')
 }

sources/src/setup-gradle.ts

@@ -6,7 +6,7 @@ import * as caches from './caching/caches'
 import * as jobSummary from './job-summary'
 import * as buildScan from './build-scan'
 
-import {loadBuildResults} from './build-results'
+import {loadBuildResults, markBuildResultsProcessed} from './build-results'
 import {CacheListener, generateCachingReport} from './caching/cache-reporting'
 import {DaemonController} from './daemon-controller'
 import {BuildScanConfig, CacheConfig, SummaryConfig, getWorkspaceDirectory} from './input-params'
@@ -63,6 +63,8 @@ export async function complete(cacheConfig: CacheConfig, summaryConfig: SummaryC
     const cachingReport = generateCachingReport(cacheListener)
     await jobSummary.generateJobSummary(buildResults, cachingReport, summaryConfig)
 
+    markBuildResultsProcessed()
+
     core.info('Completed post-action step')
 
     return true