db41 should not write [mainnav] and [metanav] if sections defined in inherited config

[Ryan J Ollos]

If [trac] mainnanv and/or metanav are defined in an inherited trac.ini, then the db41​ upgrade should not write [mainnav] and [metanav] to the environment trac.ini. Instead, a message should be printed instructing the user to migrate the sections to the new format.

​​gmessage:trac-users:jkXZjagyBBU/hHiQ1iJOCwAJ

[Ryan J Ollos]

A few things would be needed:

• Determine which parser has the value of a configuration option.
• Test if that parser is writable.
  • If yes, write to that configuration file.
  • If no, print to terminal that the user will need to manually upgrade, or just write to primary config file and print a message informing the user.

I'm debating whether to fix this at all or just add a note to TracUpgrade. In that case, some of these action items for config.py module improvements could be added to #3037.

[Ryan J Ollos]

Since inherited ini files are often shared by Trac environments we shouldn't write to any inherited ini file. If we were to do so, we'd need to add a configuration option to say whether the file is writable, and additional complexity would be needed in the Configuration class.

Added documentation:

• wiki:1.2/TracUpgrade@2#NavigationOrderingMoved
• wiki:TracUpgrade@138#NavigationOrderingMoved