Default -Dbuildtype=release cannot be overridden by native file

[frankier]

I find it quite convenience to package together build options using Meson's native files. Unfortunately if I try to set the build type in a native file like e.g.:

[built-in options]
buildtype = 'debug'

this will not override the -Dbuildtype given by meson-python here (even though it's given earlier in the command line):

meson-python/mesonpy/__init__.py

Line 874 in cfcfb35

'-Dbuildtype=release',

I'm not sure whether this is something that should be fixed in Meson or meson-python. One workaround could be to put these defaults in a native file specified earlier in the command line. This should cause them to be overwritten by the user native file correctly.

[rgommers]

Hi @frankier, thanks for the question. I don't think this is easy to change. The -Dbuildtype=release is passed as a build option to meson setup, and the precedence rules for passing build options is (from highest to lowest):

1. -D build options
2. Native and cross files
3. Project defaults, given in project() in the top-level meson.build

We're passing -Dbuildtype=release to ensure getting release rather than debug builds when end users build from source with pip install ., and commonly projects use project() to default to debug/debugoptimized builds when building locally (e.g. with spin).

Hence, to get a debug build when invoking the build through a build frontend (pip, uv, pypa/build), you should pass it as -Dbuildtype=.

[rgommers]

Actually, on re-reading this, it occurred to me that we could change our implementation to pass the release build type in a native/cross file. That should be backwards compatible and will be easier to override.