fix: bump changelog for prerelease without commits

[eduardocardoso]

Description

This changes lets the changelog be generated for version bumps from a prerelease version without new commits, which the bump command already allows.

Checklist

• Add test cases to all the changes you introduce
• Run ./scripts/format and ./scripts/test locally to ensure this change passes linter check and test
• Test the changes on the local machine manually
• Update the documentation for the changes

Expected behavior

User should be able to bump a prerelease version and generate a changelog for the new version without adding new commits

Steps to Test This Pull Request

1. Generate a prerelease version with bump command: cz bump --changelog --prerelease alpha
2. Generate a new version with bump command without adding new commits: cz bump --changelog [--prerelease beta]

Current behavior:

Fails when attempting to generate the changelog with --changelog flag

$ cz bump --changelog --prerelease alpha --yes
bump: release 0.37.0 → 0.38.0a0

Automatically generated by Commitizen.

tag to create: v0.38.0a0
increment detected: MINOR

[main 013cdd0] bump: release 0.37.0 → 0.38.0a0
 4 files changed, 9 insertions(+), 3 deletions(-)

Done!
$ cz bump --changelog --prerelease rc --yes
bump: release 0.38.0a0 → 0.38.0rc0

Automatically generated by Commitizen.

tag to create: v0.38.0rc0

No commits found

Expected behavior:

Should bump version and generate changelog with empty change list

$ cz bump --changelog --prerelease alpha --yes
bump: release 0.37.0 → 0.38.0a0

Automatically generated by Commitizen.

tag to create: v0.38.0a0
increment detected: MINOR

[main 013cdd0] bump: release 0.37.0 → 0.38.0a0
 4 files changed, 9 insertions(+), 3 deletions(-)

Done!
$ cz bump --changelog --prerelease rc --yes
bump: release 0.38.0a0 → 0.38.0rc0

Automatically generated by Commitizen.

tag to create: v0.38.0rc0

[main b7c5999] bump: release 0.38.0a0 → 0.38.0rc0
 4 files changed, 5 insertions(+), 3 deletions(-)

Done!

Additional context

[woile]

LGTM, could you also update the complexity to 13?
https://github.com/commitizen-tools/commitizen/blob/master/setup.cfg#L39
That will make the tests pass and I think it's safe to use 13.

Thank you so much 🎉

[eduardocardoso]

@woile done, thanks!

[woile]

Could you please rebase? Thanks!

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (1153908) 97.42% compared to head (ca725f2) 97.43%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #681   +/-   ##
=======================================
  Coverage   97.42%   97.43%           
=======================================
  Files          42       42           
  Lines        2022     2027    +5     
=======================================
+ Hits         1970     1975    +5     
  Misses         52       52           

Flag	Coverage Δ
unittests	97.43% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
commitizen/__version__.py	100.00% <100.00%> (ø)
commitizen/changelog.py	100.00% <100.00%> (ø)
commitizen/commands/changelog.py	98.94% <100.00%> (+0.03%)	⬆️

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[eduardocardoso]

@woile rebased ✅

[jenstroeger]

@woile any chance we can merge and release this soon, please?