feat(generate) return non-zero code or page error (#4991)

[loomchild]

Introduce --fail-on-page-error option that will cause nuxt generate to return non-zero status code when it encounters a page generation error. This is useful to let CI know that something went wrong.

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

Resolves: #4991
This PR is a result of the discussion under this ticket and the fact that nuxt-generate-cluster implements similar feature: see nuxt-community/nuxt-generate-cluster#17.

This feature allows nuxt generate to return non-zero status code in case of page generation error. This is useful to let CI know that something went wrong, otherwise such issues might get unnoticed for a long time.

In order to avoid changing existing behavior and introducing a breaking change I am proposing to add a parameter --fail-on-page-error. Only if this parameter is present the error status code will be returned.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

Note - I am not sure if it requires documentation update and where I should update it, but I am happy to do it if needed. For the moment I have added a option description which will be available when running nuxt generate --help.

[codecov-io]

Codecov Report

Merging #5195 into dev will increase coverage by <.01%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##              dev    #5195      +/-   ##
==========================================
+ Coverage   96.31%   96.32%   +<.01%     
==========================================
  Files          73       73              
  Lines        2472     2474       +2     
  Branches      626      627       +1     
==========================================
+ Hits         2381     2383       +2     
  Misses         76       76              
  Partials       15       15

Impacted Files	Coverage Δ
packages/cli/src/commands/generate.js	95% <66.66%> (-5%)	⬇️
packages/vue-renderer/src/renderer.js	94.84% <0%> (+0.51%)	⬆️

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[loomchild]

Yay, my first PR to Nuxt. Thanks guys!

[pimlie]

@loomchild Great work, that many more may follow! :)