Previously CMake may generate incomplete transitive requirements in
CMakeFiles/<target>.dir/CXXModules.json and therefore in module mapper
for compiler, when source files were listed in CMakeList.txt in a
certain order.
This commit fixes the problem by correctly tracking unfinished
transitive requirements computation of module units.
There have been a simple circular test case whose circular dependency
was reported by build system. Now with this correct implementation it's
reported by CMake generating module mappers.
Add two test cases for transitive requirements computation, one with
adding source files in hardcoded order, and the other in randomized
order.
Fixes: #25465
This allows collation to give a useful error message when it finds usage
of a private module rather than collation just not informing the
compilation and the compiler erroring out about not being able to import
unknown modules (which exists, but it was not told about due to
visibility).
Fixes: #24652
This structure allows representing whether a module is private in order
to give a more useful error message when its usage is attempted from
another target.
The call site already owns a path it doesn't need when the callback
returns. Hand ownership to the callback so it can optionally mutate
the path without necessarily allocating.
These patches now support the `-MF` output, so remove the `none` support
added just for the old patchset which did not use it.
Also update the flag name to `-fmodule-output=`.
Due to the new Clang module mapper flag, use a new experimental support
UUID as well.
