Use SHA-1 on experimental caches

Reviewed By: jeanlauliac

Differential Revision: D7399785

fbshipit-source-id: c8e842390e27d7954ca78dcd5c4b7e2a115d1b9d

packages/metro/src/Bundler/index.js

@@ -291,9 +291,9 @@ class Bundler {
         // This is the hash related to the global Bundler config.
         this._baseHash,
 
-        // Path and code.
+        // Path and code hash.
         module.localPath,
-        code,
+        (await this.getDependencyGraph()).getSha1(module.path),
 
         // We cannot include "transformCodeOptions" because of "projectRoot".
         assetDataPlugins,

packages/metro/src/node-haste/DependencyGraph.js

@@ -109,6 +109,7 @@ class DependencyGraph extends EventEmitter {
     useWatchman?: boolean = true,
   ): JestHasteMap {
     return new JestHasteMap({
+      computeSha1: true,
       extensions: opts.sourceExts.concat(opts.assetExts),
       forceNodeFilesystemAPI: !useWatchman,
       hasteImplModulePath: opts.hasteImplModulePath,
@@ -234,6 +235,17 @@ class DependencyGraph extends EventEmitter {
     return result.dependencies;
   }
 
+  getSha1(filename: string): string {
+    // $FlowFixMe: TODO T27501330: Use getSha1 from HasteFS.
+    const sha1 = this._hasteFS._files[filename][4];
+
+    if (!sha1) {
+      throw new ReferenceError(`SHA-1 for file ${filename} is not computed`);
+    }
+
+    return sha1;
+  }
+
   getWatcher() {
     return this._haste;
   }