HMR triggers full reload unnecessarily in vite@2.6.0-beta.2

[fwouts]

Describe the bug

#5037 introduced a regression where, in very specific circumstances, the page is fully reloaded instead of a specific module being refreshed.

Using Vite 2.6.0-beta.0 (correct behaviour)

Screen.Recording.2021-09-24.at.12.51.12.pm.mov

Using Vite 2.6.0-beta.2 (incorrect behaviour)

Screen.Recording.2021-09-24.at.12.51.56.pm.mov

Reproduction

I tried very hard to reproduce this in a simple app, but I wasn't able to. It seems to be a particular pattern that React Preview exhibits, potentially because of its heavy usage of virtual files. Also, it uses a /preview/ prefix in its Vite configuration.

To reproduce:

• Check out https://github.com/zenclabs/hungry sample app (main branch)
• Force vite@2.6.0-beta.2 with the following in package.json:

"resolutions": {
    "vite": "2.6.0-beta.2"
  }

• Install deps
• Run yarn reactpreview -v and open http://localhost:8120/?p=src/screens/pick-restaurant/PickRestaurant.tsx:PickRestaurant then update SearchBar.tsx as shown in the video. Notice the full reload.

Potential cause

I noticed that #5037 removed some url.replace(base, '/') calls. I'm not sure what they were for, but reverting just these two lines seems to fix everything. I'll send a PR and we can discuss there?

System Info

System:
    OS: macOS 11.5.2
    CPU: (8) arm64 Apple M1
    Memory: 215.19 MB / 8.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 16.9.1 - ~/.nvm/versions/node/v16.9.1/bin/node
    Yarn: 1.22.11 - /usr/local/bin/yarn
    npm: 7.21.1 - ~/.nvm/versions/node/v16.9.1/bin/npm
  Browsers:
    Chrome: 93.0.4577.82
    Firefox: 92.0
    Safari: 14.1.2
  npmPackages:
    vite: 2.6.0-beta.2 => 2.6.0-beta.2

Used Package Manager

yarn

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to https://github.com/vuejs/vue-next instead.
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• The provided reproduction is a minimal reproducible example of the bug.