feat(conditional-page-builds): track potentially unsafe Node.js builtin modules usage

[pieh]

Note: best to check changes with whitespace changes hidden as I did some try/catch wrapping which just changed indentation a lot

Description

Usage of certain Node.js builtin modules in SSR (primarly from gatsby-ssr, but not limited to it) risks that our tracking wether html file can be reused from previous build is not catching all the cases that ideally should case file to rebuild.

Current list of builtin modules that are "tracked":

    const builtinModulesToTrack = [
      `fs`,
      `http`,
      `http2`,
      `https`,
      `child_process`,
    ]

In those cases those modules are used we set a flag so that following builds would rebuild all the pages as we can't be certain of the exact "contract" usage of those APIs have. We also do display warnings about those (including code location) and that future builds will be full ones and not selective:

Related Issues

[ch24532]

[pieh]

this is because filename (child_process.js doesn't match our eslint rule :( )

[pieh]

This hurts my feelings, but I essentially need "context" that "unconnected" arbitrary code can access and push to.

[wardpeet]

I need to try it, some small nits and questions.

[wardpeet]

did anything change except this?

[pieh]

I suggest checking with "hide whitespace changes" ( https://github.com/gatsbyjs/gatsby/pull/29560/files?w=1#diff-4cd5b620539129dfa79254b9cdae3bd9b619426b83b412d2647cfb416730d362 )

This whole file added

// for this to work we need this function to be sync or at least ensure there is single execution of it at a time
  global.unsafeBuiltinUsage = []

at the start of the function, changed return to return object instead of string and wrapped everything in try/catch to decorate caught error with unsafeBuiltinUsage to not "lose" it's usage (even tho probably this is might be not needed, it feels safer to do)

[wardpeet]

How does someone clear this flag? Running gatsby clean and/or gatsby cleans cache?

[pieh]

this flag gets cleared when SSR compilation hash changes (as long as we use same SSR compilation hash is used - we know that if previous build used unsafe builtin methods - following builds will continue to do so, because it's the same code running).

Changing SSR compilation hash also cause all pages to be rebuild so we are "covered" for that case

[wardpeet]

L