[Lldb-commits] [PATCH] D74917: [lldb/cmake] Fail configuration if a required swig dependency is not met.

[Matt Davis via Phabricator via lldb-commits]

mattd added a comment.

In D74917#1885621 <https://reviews.llvm.org/D74917#1885621>, @JDevlieghere wrote:

> In D74917#1885615 <https://reviews.llvm.org/D74917#1885615>, @mattd wrote:
>
> > In D74917#1885590 <https://reviews.llvm.org/D74917#1885590>, @JDevlieghere wrote:
> >
> > > It should never be possible for `LLDB_ENABLE_PYTHON` to be true but `SWIG_FOUND` to be false. The modules `FindPythonInterpAndLibs.cmake` and `FindLuaAndSwig.cmake` should fail early when SWIG isn't found.
> >
> >
> > Thanks for taking a look.  Would you be okay with making the status `message()` in `FindPythonInterpAndLibs.cmake` and `FindLuaAndSwig.cmake` fatal, that way the dependency error is clearer?
>
>
> That would defeat the purpose of auto-detecting these dependencies. Please take a look at D71306 <https://reviews.llvm.org/D71306> for all the details. The summary is that all optional dependencies default to `Auto`: where we enable them if we can find them. You can override this behavior by passing `LLDB_ENABLE_PYTHON=ON` to CMake, in which case not finding Python (or SWIG) will be a fatal error.


Thanks for the clarification there.

> I agree that it can be confusing to figure out that Python got disabled because SWIG wasn't found. Currently we call `find_package` with `QUIET` from `FindPythonInterpAndLibs.cmake` and `FindLuaAndSwig.cmake`. I think we should remove that so that the user gets more information in CMake's configuration output. Would that address your concerns?

Ah, yes, dropping the `QUIET` produces meaningful insight as to what might be missing. I think others, who might not have all the dependencies, might find this level of verbosity clearer, so that they can more quickly understand what is missing in their build environment.


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https://reviews.llvm.org/D74917