Summary

Background

We have a way to skip re-building chunk graph, that is, when module graph has no change, no incoming outgoing changes, we can skip creating chunks for current compilation.

We detect module graph change in make phase before, which is not exactly accurate.

Issue

Many optimizations are applied after make phase, for example, innerGraph, sideEffects and usedExports, they can change module graph as well. To solve this, we did a lot of hack to detect change according to many aspects, even dependency.ids, as it can affect how sideEffects optimized.

Current solution

Now I move this detection later right before build_chunk_graph, and compare current outgoings with last compilation, in this stage, all optimizations are already applied.

Long term solution

When incremental for build_chunk_graph is stable, we no longer need to detect the changes and skip creating chunks, as incremental build chunks is performant enough

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).