Use recursive ctime to determine plugin cache expiration

Summary:
Disabling `atime` on Linux is quite common. (I don't have data to back this up,
but with my sample size of n=1, 100% fall into this bucket.) In that case,
the plugins will be cached indefinitely.

Using `ctime` on the directory doesn't really mean anything because it is
only affected by changes *to* the directory, not the files inside.

So, let's do this right and use the most recent change to any of the files
*inside* the directory instead.

Reviewed By: danielbuechele

Differential Revision: D9479491

fbshipit-source-id: 6945d7bf87defa67679cacdaf0a978d8ff1770c3

static/compilePlugins.js

@@ -8,6 +8,8 @@
 const path = require('path');
 const fs = require('fs');
 const metro = require('metro');
+const util = require('util');
+const recursiveReaddir = require('recursive-readdir');
 const HOME_DIR = require('os').homedir();
 
 module.exports = (reloadCallback, pluginPaths, pluginCache) => {
@@ -135,6 +137,15 @@ function changeExport(path) {
     );
   fs.writeFileSync(path, file);
 }
+function mostRecentlyChanged(dir) {
+  return util
+    .promisify(recursiveReaddir)(dir)
+    .then(files =>
+      files
+        .map(f => fs.lstatSync(f).ctime)
+        .reduce((a, b) => (a > b ? a : b), new Date(0)),
+    );
+}
 function compilePlugin(
   {rootDir, name, entry, packageJSON},
   force,
@@ -145,41 +156,43 @@ function compilePlugin(
     const out = path.join(pluginCache, fileName);
     const result = Object.assign({}, packageJSON, {rootDir, name, entry, out});
     // check if plugin needs to be compiled
-    if (
+    mostRecentlyChanged(rootDir).then(rootDirCtime => {
-      !force &&
+      if (
-      fs.existsSync(out) &&
+        !force &&
-      fs.lstatSync(rootDir).atime < fs.lstatSync(out).ctime
+        fs.existsSync(out) &&
-    ) {
+        rootDirCtime < fs.lstatSync(out).ctime
-      // eslint-disable-next-line no-console
+      ) {
-      console.log(`🥫  Using cached version of ${name}...`);
+        // eslint-disable-next-line no-console
-      resolve(result);
+        console.log(`🥫  Using cached version of ${name}...`);
-    } else {
+        resolve(result);
-      console.log(`⚙️  Compiling ${name}...`); // eslint-disable-line no-console
+      } else {
-      metro
+        console.log(`⚙️  Compiling ${name}...`); // eslint-disable-line no-console
-        .runBuild({
+        metro
-          config: {
+          .runBuild({
-            getProjectRoots: () => [rootDir, path.join(__dirname, '..')],
+            config: {
-            getTransformModulePath: () =>
+              getProjectRoots: () => [rootDir, path.join(__dirname, '..')],
-              path.join(__dirname, 'transforms', 'index.js'),
+              getTransformModulePath: () =>
-            // a custom hash function is required, because by default metro starts
+                path.join(__dirname, 'transforms', 'index.js'),
-            // numbering the modules by 1. This means all plugins would start at
+              // a custom hash function is required, because by default metro starts
-            // ID 1, which causes a clash. This is why we have a custom IDFactory.
+              // numbering the modules by 1. This means all plugins would start at
-            createModuleIdFactory,
+              // ID 1, which causes a clash. This is why we have a custom IDFactory.
-          },
+              createModuleIdFactory,
-          dev: false,
+            },
-          entry,
+            dev: false,
-          out,
+            entry,
-        })
+            out,
-        .then(() => {
+          })
-          changeExport(out);
+          .then(() => {
-          resolve(result);
+            changeExport(out);
-        })
+            resolve(result);
-        .catch(err => {
+          })
-          console.error(
+          .catch(err => {
-            `❌  Plugin ${name} is ignored, because it could not be compiled.`,
+            console.error(
-          );
+              `❌  Plugin ${name} is ignored, because it could not be compiled.`,
-          console.error(err);
+            );
-        });
+            console.error(err);
-    }
+          });
+      }
+    });
   });
 }

static/package.json

@@ -12,6 +12,7 @@
     "babel-plugin-transform-object-rest-spread": "^7.0.0-beta.3",
     "babel-preset-react": "^7.0.0-beta.3",
     "babylon": "^7.0.0-beta.40",
-    "metro": "^0.28.0"
+    "metro": "^0.28.0",
+    "recursive-readdir": "2.2.2"
   }
 }

static/yarn.lock

@@ -2252,7 +2252,7 @@ min-document@^2.19.0:
   dependencies:
     dom-walk "^0.1.0"
 
-minimatch@^3.0.0, minimatch@^3.0.2, minimatch@^3.0.4:
+minimatch@3.0.4, minimatch@^3.0.0, minimatch@^3.0.2, minimatch@^3.0.4:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
   dependencies:
@@ -2574,6 +2574,12 @@ readable-stream@^2.0.1, readable-stream@^2.0.6, readable-stream@^2.1.4, readable
     string_decoder "~1.0.3"
     util-deprecate "~1.0.1"
 
+recursive-readdir@2.2.2:
+  version "2.2.2"
+  resolved "https://registry.yarnpkg.com/recursive-readdir/-/recursive-readdir-2.2.2.tgz#9946fb3274e1628de6e36b2f6714953b4845094f"
+  dependencies:
+    minimatch "3.0.4"
+
 regenerate@^1.2.1:
   version "1.3.3"
   resolved "https://registry.yarnpkg.com/regenerate/-/regenerate-1.3.3.tgz#0c336d3980553d755c39b586ae3b20aa49c82b7f"