Only process build results once (#133)

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' at the end of the job, we can avoid this scenario.

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, '')
 }