perf(vite): cache normalized inspect module ids

packages/vite/src/node/__tests__/inspect-context.test.ts

@@ -1286,3 +1286,26 @@ describe('vite inspect hook timing', () => {
     })
   })
 })
+
+describe('vite inspect public module ids', () => {
+  it('normalizes dependency ids relative to the current root', async () => {
+    const { envCtx, vite } = await createFixture()
+    const id = '/project/node_modules/dep/index.js?v=abc123'
+
+    expect(envCtx.getPublicModuleId(id)).toBe('./node_modules/dep/index.js')
+    expect(envCtx.getPublicModuleId(id)).toBe('./node_modules/dep/index.js')
+
+    // A cached id must follow a root change instead of returning the stale result.
+    ;(vite.config as { root: string }).root = '/project/node_modules'
+    expect(envCtx.getPublicModuleId(id)).toBe('./dep/index.js')
+  })
+
+  it('keeps returning correct ids after the cache is cleared at its size limit', async () => {
+    const { envCtx } = await createFixture()
+    for (let index = 0; index < 10_001; index++)
+      expect(envCtx.getPublicModuleId(`/project/node_modules/dep/m${index}.js`)).toBe(`./node_modules/dep/m${index}.js`)
+
+    expect(envCtx.getPublicModuleId('/project/node_modules/dep/m0.js')).toBe('./node_modules/dep/m0.js')
+    expect(envCtx.getPublicModuleId('/src/main.ts')).toBe('/src/main.ts')
+  })
+})

packages/vite/src/node/inspect/context.ts

@@ -180,10 +180,16 @@ export class ViteInspectViteContext {
   }
 }
 
+// Ids can carry HMR timestamps, so cap the cache instead of letting it grow for the whole session.
+const MAX_PUBLIC_MODULE_ID_CACHE_SIZE = 10_000
+
 export class ViteInspectEnvironmentContext {
   readonly scope: string
   private pluginCallCount = 0
   private graphModuleIdResolver?: ReturnType<typeof createGraphModuleIdResolver>
+  // Every hook call records its module id, so the same id is normalized once per plugin per request.
+  private readonly publicModuleIds = new Map<string, string>()
+  private publicModuleIdsRoot?: string
 
   constructor(
     readonly inspectContext: ViteInspectContext,
@@ -336,7 +342,17 @@ export class ViteInspectEnvironmentContext {
   }
 
   getPublicModuleId(id: string): string {
-    return normalizeModuleId(this.normalizeId(id), this.getModuleIdBaseRoot())
+    const root = this.getModuleIdBaseRoot()
+    if (root !== this.publicModuleIdsRoot || this.publicModuleIds.size >= MAX_PUBLIC_MODULE_ID_CACHE_SIZE) {
+      this.publicModuleIds.clear()
+      this.publicModuleIdsRoot = root
+    }
+    let publicId = this.publicModuleIds.get(id)
+    if (publicId === undefined) {
+      publicId = normalizeModuleId(this.normalizeId(id), root)
+      this.publicModuleIds.set(id, publicId)
+    }
+    return publicId
   }
 
   async getModuleId(id: string): Promise<string> {