Plugins can cause duplicate entries in records files

[ojacobson]

Webpack version: 1.13.0

Please tell us about your environment: Mac OS 10.11.mumble, Node v6.2.2

Current behavior:

When running webpack (npm run webpack) in this project, Webpack adds new entries to webpack-records.json, even though there are no code changes. Every run adds new records, causing the file to grow without bound.

Example diff:

diff --git a/webpack-records.json b/webpack-records.json
index da2c839..05569d8 100644
--- a/webpack-records.json
+++ b/webpack-records.json
@@ -13,6 +13,20 @@
         "byName": {},
         "byBlocks": {}
       }
+    },
+    {
+      "nextFreeModuleId": 2,
+      "modules": {
+        "byIdentifier": {
+          "node_modules/css-loader/index.js?sourceMap!src/app.css": 0,
+          "node_modules/css-loader/lib/css-base.js": 1
+        }
+      },
+      "nextFreeChunkId": 1,
+      "chunks": {
+        "byName": {},
+        "byBlocks": {}
+      }
     }
   ],
   "nextFreeModuleId": 4,

(The added records are identical to records already present in the file.)

The duplicate records appear in the section associated with the ExtractTextPlugin, but I've been able to reproduce this with other plugins, as well (including HtmlPlugin).

Expected/desired behavior:

• Records files change only when modules are added to or removed from the bundle.
• Duplicate sections do not appear in records files.

[TheLarkInn]

Would you mind checking this in webpack@2?

[Jessidhia]

This might be a problem with extract-text-webpack-plugin (or with child compiler handling), or at least I encountered a similar issue a few months ago with webpack@2.1.0-beta.21 + extract-text-webpack-plugin@2.1.0-beta.3.

On every build that used the recordsPath, the "extract-text-webpack-plugin" array in the records JSON would be appended with a new modules/chunks object.

This was a "disposable" project so I didn't pay it much mind, and I periodically delete the records anyway to re-optimize the chunk IDs.

[kisenka]

@sokra does it mean that child compilation produce right HMR update files?