Don’t reload package manifest when a header is added

[MaxDesiatov]

Currently, any new header file causes a package reload. This means that while background indexing is writing header files into the index build directory, the package will get reloaded, which is unnecessary.

[MaxDesiatov]

@swift-ci test

[ahoppen]

While this fixes the most common issue that I have seen during a build, there are a couple of others that this change would not cover. For example, SourceKit-LSP is operating on a .index-build build folder when background indexing is enabled. Now say I run the first build on the command line into .build, which will clone the dependencies and thus generate .swift files in .build. For all of these files, we’ll consider them as affecting the build settings for SourceKit-LSP because they match the .swift rule.

Is there any way in SwiftPM to figure out whether a file is in a Sources/Tests folder of an existing target or the build plugin equivalent of these? Such a check would fix the scenario described above.

But thanks for the fix. I think this is very valuable to take on its own because it should fix the majority of package manifest reloads.

[MaxDesiatov]

@swift-ci test

[MaxDesiatov]

@swift-ci test windows

[MaxDesiatov]

Is there any way in SwiftPM to figure out whether a file is in a Sources/Tests folder of an existing target or the build plugin equivalent of these? Such a check would fix the scenario described above.

There's a complication as there can be files generated by plugins in the build directory, and we don't know which files until we run those plugins.

[ahoppen]

I just drafted an implementation that relies on directories in the build plan instead of file extensions, which also avoids the issue of .swift files created in locations that don’t affect the build, which I described above

#7699