feat!: rewrite external copy with multi version hoisting support

[pi0]

Resolves #572

Based on amazing work from @mahdiboomeri (#758) this PR introduces a full rewrite of the external copy mechanism.

Previously if multiple versions of an external library were being used by traced externals, we used this strategy:

• In case of minor version conflicts, pick the latest to use for all libs
• In case of major version conflicts, warn and pick the latest semver-major one

This causes unresolvable issues especially when sub-dependencies are conflicting.

With this refactor, we respect hoisted structure of package manager and map it into .output/server/node_modules:

• Create a normalized list of all traced files and their parents
• Create a normalized list of all relevant package/versions from traced files
• For each package
  • If there is only one traced version detected, copy it as as
  • If more than one traced version is detected, copy to node_modules/{name}@{version} and symlink to node_modules/{parent}/node_modules/{name} for each parent. If no parent modules are detected, hoist it to top level as default (user's version)

In case of having issues with new implementation in nitropack v2, you can opt to use legacy externals:

experimental: {
  // Use nitropack v1 behavior
  legacyExternals: true
}

[codecov]

Codecov Report

Merging #782 (f1c9ce4) into main (f812c81) will decrease coverage by 3.45%.
The diff coverage is 36.83%.

❗ Current head f1c9ce4 differs from pull request most recent head 71641e0. Consider uploading reports for the commit 71641e0 to get more accurate results

@@            Coverage Diff             @@
##             main     #782      +/-   ##
==========================================
- Coverage   70.63%   67.17%   -3.46%     
==========================================
  Files          57       58       +1     
  Lines        5299     5716     +417     
  Branches      607      605       -2     
==========================================
+ Hits         3743     3840      +97     
- Misses       1549     1869     +320     
  Partials        7        7              

Impacted Files	Coverage Δ
src/rollup/plugins/externals-legacy.ts	6.80% <6.80%> (ø)
src/rollup/config.ts	92.12% <80.00%> (-0.17%)	⬇️
src/rollup/plugins/externals.ts	94.90% <98.13%> (-0.07%)	⬇️
src/types/nitro.ts	100.00% <100.00%> (ø)

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[mahdiboomeri]

@pi0 I added the options as a workaround if they were some edge cases that weren't covered (such as a package that doesn't follow semver), but IMO the new approach seems reliable enough to skip that.

[itpropro]

Any updates for this @pi0 ?

[pi0]

Updated implementation with parent-level hosting for nested support, windows support using junctions (not portable), and alias support.

Although new implementation should be much better for handling hoisting situations and allow better enhancements using new clearer data-structures, it can be buggy without testing on real-world installs. So let's get it a spin.

Also there is new experimental.legacyExternals flag to allows an escape hatch to use v1 behavior.