diff --git a/packages/playwright/src/reporters/merge.ts b/packages/playwright/src/reporters/merge.ts
index e91c7305ec..5eedcac136 100644
--- a/packages/playwright/src/reporters/merge.ts
+++ b/packages/playwright/src/reporters/merge.ts
@@ -194,25 +194,22 @@ async function mergeEvents(dir: string, shardReportFiles: string[], stringPool:
   printStatus(`merging events`);
 
   const reports: ReportData[] = [];
-  const testIdsUsedInOtherBlobs = new Set<string>();
+  const globalTestIdSet = new Set<string>();
 
   for (let i = 0; i < blobs.length; ++i) {
     // Generate unique salt for each blob.
     const { parsedEvents, metadata, localPath } = blobs[i];
     const eventPatchers = new JsonEventPatchers();
-    const testIdsUsedInThisBlob = new Set<string>();
     eventPatchers.patchers.push(new IdsPatcher(
         stringPool,
         metadata.name,
         String(i),
-        testIdsUsedInThisBlob,
-        testIdsUsedInOtherBlobs,
+        globalTestIdSet,
     ));
     // Only patch path separators if we are merging reports with explicit config.
     if (rootDirOverride)
       eventPatchers.patchers.push(new PathSeparatorPatcher(metadata.pathSeparator));
     eventPatchers.patchEvents(parsedEvents);
-    testIdsUsedInThisBlob.forEach(id => testIdsUsedInOtherBlobs.add(id));
 
     for (const event of parsedEvents) {
       if (event.method === 'onConfigure')
@@ -368,22 +365,19 @@ class IdsPatcher {
   private _botName: string | undefined;
   private _salt: string;
   private _testIdsMap: Map<string, string>;
-  private _testIdsUsedInThisBlob: Set<string>;
-  private _testIdsUsedInOtherBlobs: Set<string>;
+  private _globalTestIdSet: Set<string>;
 
   constructor(
     stringPool: StringInternPool,
     botName: string | undefined,
     salt: string,
-    testIdsUsedInThisBlob: Set<string>,
-    testIdsUsedInOtherBlobs: Set<string>,
+    globalTestIdSet: Set<string>,
   ) {
     this._stringPool = stringPool;
     this._botName = botName;
     this._salt = salt;
     this._testIdsMap = new Map();
-    this._testIdsUsedInThisBlob = testIdsUsedInThisBlob;
-    this._testIdsUsedInOtherBlobs = testIdsUsedInOtherBlobs;
+    this._globalTestIdSet = globalTestIdSet;
   }
 
   patchEvent(event: JsonEvent) {
@@ -431,14 +425,14 @@ class IdsPatcher {
     if (this._testIdsMap.has(t1))
       // already mapped
       return this._testIdsMap.get(t1)!;
-    if (this._testIdsUsedInOtherBlobs.has(t1)) {
+    if (this._globalTestIdSet.has(t1)) {
       // test id is used in another blob, so we need to salt it.
       const t2 = this._stringPool.internString(testId + this._salt);
-      this._testIdsUsedInThisBlob.add(t2);
+      this._globalTestIdSet.add(t2);
       this._testIdsMap.set(t1, t2);
       return t2;
     }
-    this._testIdsUsedInThisBlob.add(t1);
+    this._globalTestIdSet.add(t1);
     this._testIdsMap.set(t1, t1);
     return t1;
   }