Do not skip processing modules restored from cache

[Silic0nS0ldier]

Inclusion in compilation.builtModules (which is under documented) does not indicate a module has already been built, usage within plugins included in webpack confirms this.

The current behaviour lead to an incomplete Storybook build (missing documentation) when our custom cache plugin was enabled. The changes in this PR are already applied internally via a patch.

Examples

lib/Compilation.js

By default, modules are only added to compilation.builtModules when the module itself indicates it needs to be built (modules served from the cache via compiler.cache.hooks.get do not need to be built).

https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/Compilation.js#L1387-L1405

lib/optimize/ModuleConcatenationPlugin.js

Concatenated modules are only marked as built when an included module is included in compilation.builtModules.

https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/optimize/ModuleConcatenationPlugin.js#L439-L442

lib/stats/DefaultStatsFactoryPlugin.js

compilation.builtModules is one of the indicators used to determine if a given module was served from the cache, the other being compilation.codeGeneratedModules.

https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/stats/DefaultStatsFactoryPlugin.js#L1097-L1116

compiler.cache.hooks.get Examples

• https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/cache/MemoryCachePlugin.js#L30
• https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/cache/IdleFileCachePlugin.js#L66
• https://github.com/webpack/webpack/blob/34e2561addb0f65a7a6fb0ce7ae1aea4cd1d599f/lib/cache/MemoryWithGcCachePlugin.js#L93