Allow using basedir as a root base directory for files and paths.

[tritao]

What does this PR do?

This adds some improvements to basedir so it can be used to specify a base directory for file, path and directory fields.

How does this PR change Premake's behavior?

Previously it only could be used for tokens, but now it can also affects paths, so depending on the order it's set, it might provide different results.

Anything else we should know?

Another option would be to go with a new srcdir, that also seems like a reasonable approach to take.

So feel free to provide some feedback if you have preferences how this should work.

Did you check all the boxes?

• Focus on a single fix or feature; remove any unrelated formatting or code changes
• Add unit tests showing fix or feature works; all tests pass
• Mention any related issues (put closes #XXXX in comment to auto-close issue when PR is merged)
• Follow our coding conventions
• Minimize the number of commits
• Align documentation to your changes

Closes #2129.

[nickclark2016]

This reads as an extension of existing behavior, rather than breaking the existing behavior. Would this be a correct interpretation of your goals?

[nickclark2016]

This reads as an extension of existing behavior, rather than breaking the existing behavior. Would this be a correct interpretation of your goals?

@tritao Just pinging for response here

[tritao]

This reads as an extension of existing behavior, rather than breaking the existing behavior. Would this be a correct interpretation of your goals?

Yes, it's an extension of existing behavior. I think it should be safe to merge, my only concern is that basedir is already used for a niche use case (generating completely portable project files), but it's barely documented and there's like a single test for it. Since that is still available and works, it seems reasonable to use the same property for the functionality I introduced here, but I could also be reasoned to introduce a new distinct API.

[nickclark2016]

We are still in API break territory since we haven't hit 5.0. It could be worth some investigation into projects using Premake to see if they're using the undocumented behavior (hopefully no Hyrum's Law yet).

[nickclark2016]

The more I think about this, I think the better it is to get the @premake/full-team thoughts, since it would be a potentially breaking change for some.

[samsinsane]

I don't think I'm really following what basedir currently does from what has been said, and the docs suggest it should do what the current PR implements - so I'm not sure what basedir is for, but if the functionality is different then maybe we should have a new API to avoid the inevitable complaints.

I haven't tested anything, but does files { "**.cpp" } give different results after each call to basedir? For example:

basedir "a"
files { "**.cpp" }
basedir "b"
files { "**.cpp" }

Is this the equivalent of files { "a/**.cpp", "b/**.cpp" }? If not, should it be? I didn't see a test for this, so should probably include that regardless of which way it works.

What do the changes in oven.lua do? I might be wrong, but I don't think it's required for the api.lua changes?

[nickclark2016]

Personally, I'm fine with breaking the API here. At a minimum, it's a pretty minor break and we can put it in the release notes. Can you provide a minimum example of what would break?