Discuss: How to avoid rewriting the full config file

I’m not a fan of rewriting config files.

Feedback we had in various issues shows it’s

• ugly (it moves sections around, can affect newlines and whitespace)
• inconvenient (it introduces source control changes in places where it should not)
• dangerous (it drops comments!)
• probably unnecessary

See for example #62, #83, #87, #90, #94, #161, #163, #169, #201, #207, #217, #228. How are we going to solve this? Various things we can do:

1. Update the version in the config file, but don’t rewrite the whole file.
2. Rely on setup.cfg version.
3. Rely on the version found in the first bumpversion:file: section.
4. Don’t update the config file unless the user configures bump2version to do it.

[florisla]

Proposal:

• If version is present, use it and replace it like you would a regular file. Don’t rewrite the full config file.
• If metadata.version is present in setup.cfg, use it and replace it similarly.
• If none of both is present, simply assume that the first file section defined contains the full version number.`

Whether to modify metadata.version should be configurable. The default may be either of

• Modify if it’s present.
• Modify if it’s present and bump2version is configured in the same setup.cfg file.
• Only modify it if requested.

The latter is most compatible with current behavior, but the middle option seems more intuitive.

This takes care of whitespace issues, newline issues, dropped comments, double version definitions in setup.cfg, and redundant version definition in any config file.

[tandav]

I solved this issue by switching to bumpver. Nice package which is not listed in RELATED.md alternatives. It supports setup.cfg and does not rewrites it, no whitespace issues.