perf(transform): skip eval cache for __mkPreval evaluations

change/@griffel-transform-d54d4756-3495-4c37-bf22-5076d3c8fd83.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "perf: skip eval cache for __mkPreval entry-point evaluations",
+  "packageName": "@griffel/transform",
+  "email": "olfedias@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/transform/src/evaluation/module.mts

@@ -168,7 +168,7 @@ export class Module {
     },
   );
 
-  evaluate(text: string, only: string[] | null = null): void {
+  evaluate(text: string, only: string[] | null = null, useEvalCache = true): void {
     const { filename } = this;
     // Find last matching rule (iterate backwards, break on first match)
     let action: EvalRule['action'] = 'ignore';
@@ -184,7 +184,7 @@ export class Module {
 
     const cacheKey = [this.filename, ...(only ?? [])];
 
-    if (EvalCache.has(cacheKey, text)) {
+    if (useEvalCache && EvalCache.has(cacheKey, text)) {
       this.exports = EvalCache.get(cacheKey, text);
       return;
     }
@@ -234,7 +234,9 @@ export class Module {
       }),
     );
 
-    EvalCache.set(cacheKey, text, this.exports);
+    if (useEvalCache) {
+      EvalCache.set(cacheKey, text, this.exports);
+    }
   }
 
   static invalidate = (): void => {

packages/transform/src/evaluation/vmEvaluator.mts

@@ -28,7 +28,9 @@ export const __mkPreval = (() => {
 
   try {
     const mod = new Module(filename, evaluationRules, resolveFilename);
-    mod.evaluate(codeForEvaluation, ['__mkPreval']);
+    // useEvalCache=false: each source file produces unique codeForEvaluation (different sourceCode +
+    // expressionCode), so the eval cache would never hit — skip the unnecessary hashing and map storage.
+    mod.evaluate(codeForEvaluation, ['__mkPreval'], /* useEvalCache */ false);
 
     const result = (mod.exports as { __mkPreval: unknown }).__mkPreval;