fix: prevent corruption of detectComponents() cache

fwouts · Dec 4, 2022 · c3fb8bc · c3fb8bc
1 parent 1e50a69
commit c3fb8bc
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Showing 3 changed files with 70 additions and 59 deletions.
diff --git a/core/package.json b/core/package.json
@@ -37,6 +37,7 @@
     "acorn": "^8.8.1",
     "assert-never": "^1.2.1",
     "axios": "^1.2.0",
+    "exclusive-promises": "^1.0.3",
     "express": "^4.18.2",
     "fs-extra": "^11.1.0",
     "get-port": "^5",

diff --git a/core/src/detect-components.ts b/core/src/detect-components.ts
@@ -1,5 +1,6 @@
 import type { RPCs } from "@previewjs/api";
 import type { TypeAnalyzer } from "@previewjs/type-analyzer";
+import { exclusivePromiseRunner } from "exclusive-promises";
 import fs from "fs-extra";
 import path from "path";
 import type { FrameworkPlugin, Workspace } from ".";
@@ -8,7 +9,11 @@ import { findFiles } from "./find-files";
 
 type ProjectComponents = RPCs.DetectComponentsResponse["components"];
 
-export async function detectComponents(
+// Prevent concurrent running of detectComponents()
+// to avoid corrupting the cache and optimise for cache hits.
+const oneAtATime = exclusivePromiseRunner();
+
+export function detectComponents(
   workspace: Workspace,
   frameworkPlugin: FrameworkPlugin,
   typeAnalyzer: TypeAnalyzer,
@@ -17,65 +22,69 @@ export async function detectComponents(
     forceRefresh?: boolean;
   } = {}
 ): Promise<RPCs.DetectComponentsResponse> {
-  const cacheFilePath = path.join(
-    getCacheDir(workspace.rootDirPath),
-    "components.json"
-  );
-  const absoluteFilePaths = options.filePaths
-    ? options.filePaths.map((filePath) =>
-        path.join(workspace.rootDirPath, filePath)
+  return oneAtATime(async () => {
+    const cacheFilePath = path.join(
+      getCacheDir(workspace.rootDirPath),
+      "components.json"
+    );
+    const absoluteFilePaths = options.filePaths
+      ? options.filePaths.map((filePath) =>
+          path.join(workspace.rootDirPath, filePath)
+        )
+      : await findFiles(
+          workspace.rootDirPath,
+          "**/*.@(js|jsx|ts|tsx|svelte|vue)"
+        );
+    const filePathsSet = new Set(
+      absoluteFilePaths.map((absoluteFilePath) =>
+        path
+          .relative(workspace.rootDirPath, absoluteFilePath)
+          .replace(/\\/g, "/")
       )
-    : await findFiles(
-        workspace.rootDirPath,
-        "**/*.@(js|jsx|ts|tsx|svelte|vue)"
-      );
-  const filePathsSet = new Set(
-    absoluteFilePaths.map((absoluteFilePath) =>
-      path.relative(workspace.rootDirPath, absoluteFilePath).replace(/\\/g, "/")
-    )
-  );
-  const existingCacheLastModified =
-    !options.forceRefresh && fs.existsSync(cacheFilePath)
-      ? fs.statSync(cacheFilePath).mtimeMs
-      : 0;
-  const existingCache: ProjectComponents = existingCacheLastModified
-    ? JSON.parse(fs.readFileSync(cacheFilePath, "utf8"))
-    : {};
-  const changedAbsoluteFilePaths = absoluteFilePaths.filter(
-    (absoluteFilePath) => {
-      const entry = workspace.reader.readSync(absoluteFilePath);
-      return (
-        entry?.kind === "file" &&
-        entry.lastModifiedMillis() > existingCacheLastModified
-      );
+    );
+    const existingCacheLastModified =
+      !options.forceRefresh && fs.existsSync(cacheFilePath)
+        ? fs.statSync(cacheFilePath).mtimeMs
+        : 0;
+    const existingCache: ProjectComponents = existingCacheLastModified
+      ? JSON.parse(fs.readFileSync(cacheFilePath, "utf8"))
+      : {};
+    const changedAbsoluteFilePaths = absoluteFilePaths.filter(
+      (absoluteFilePath) => {
+        const entry = workspace.reader.readSync(absoluteFilePath);
+        return (
+          entry?.kind === "file" &&
+          entry.lastModifiedMillis() > existingCacheLastModified
+        );
+      }
+    );
+    const recycledComponents = Object.fromEntries(
+      Object.entries(existingCache).filter(([filePath]) =>
+        filePathsSet.has(filePath)
+      )
+    );
+    const refreshedComponents = await detectComponentsCore(
+      workspace,
+      frameworkPlugin,
+      typeAnalyzer,
+      changedAbsoluteFilePaths
+    );
+    const allComponents = {
+      ...recycledComponents,
+      ...refreshedComponents,
+    };
+    const components = Object.keys(allComponents)
+      .sort()
+      .reduce<ProjectComponents>((ordered, filePath) => {
+        ordered[filePath] = allComponents[filePath]!;
+        return ordered;
+      }, {});
+    if (!options.filePaths) {
+      await fs.mkdirp(path.dirname(cacheFilePath));
+      await fs.writeFile(cacheFilePath, JSON.stringify(components));
     }
-  );
-  const recycledComponents = Object.fromEntries(
-    Object.entries(existingCache).filter(([filePath]) =>
-      filePathsSet.has(filePath)
-    )
-  );
-  const refreshedComponents = await detectComponentsCore(
-    workspace,
-    frameworkPlugin,
-    typeAnalyzer,
-    changedAbsoluteFilePaths
-  );
-  const allComponents = {
-    ...recycledComponents,
-    ...refreshedComponents,
-  };
-  const components = Object.keys(allComponents)
-    .sort()
-    .reduce<ProjectComponents>((ordered, filePath) => {
-      ordered[filePath] = allComponents[filePath]!;
-      return ordered;
-    }, {});
-  if (!options.filePaths) {
-    await fs.mkdirp(path.dirname(cacheFilePath));
-    await fs.writeFile(cacheFilePath, JSON.stringify(components));
-  }
-  return { components };
+    return { components };
+  });
 }
 
 async function detectComponentsCore(

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml