HTML reporter source code view is missing in some platform

[hi-ogawa]

This is the merged report from current main run and it's missing source code for macos and windows. Not sure it's related to new blob label, merge or just has been missing in html.
https://viewer.vitest.dev/?url=https://github.com/vitest-dev/vitest/actions/runs/25306824033/artifacts/6778859721

macos

ubuntu

[dokson]

@hi-ogawa I dug into this and confirmed the cause from the artifact you linked: the merged html.meta.json had 336 Linux files with source, 112 macOS and 112 Windows files with no source — exact match for the screenshots.

Root cause: the HTML reporter reads test sources from the local filesystem at merge time. When the merger runs on Linux but the blob references /Users/runner/... or C:\..., the read fails silently and the source is dropped.

Opened #10263 with a fix: embed sources in the blob on the producer side and propagate them through state.blobs.sources, with a fallback to fs.readFile so non-merge runs are unchanged. Includes an e2e test that simulates the cross-OS scenario by renaming fixtures between the blob run and the merge run.