ninja backend: don't hide all compiler warnings for transpiled languages #12597
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This was originally added for vala only, with the rationale that vala generates bad code that has warnings. Unfortunately, the rationale was fatally flawed. The compiler warns about a number of things, which the user can control depending on their code (or their code generator's code), but some of those things are absolutely critical to warn about. In particular, GCC 14 and clang 17 are updating their defaults to warn -- and error by default for -- invalid C code that breaks the standard, but has been silently accepted for over 20 years "because lots of people do it". The code in question is UB, and compilers will generate faulty machine code that behaves erroneously and probably has a mass of CVEs waiting to happen. Compiler warnings are NOT safe to just... universally turn off. Compiler warnings could be either: - coding style lints - threatening statements that the code is factually and behaviorally wrong There is no magic bullet to ignore the former while respecting the latter. And the very last thing we should ever do is pass `-w`, since that causes ALL warnings to be disabled, even the manually added `-Werror=XXX`. If vala generated code creates warnings, then the vala compiler can decrease the log level by generating better code, or by adding warning suppression pragmas for *specific* issues, such as unused functions.
no_warn_args is unused. Its only purpose was to implement automatic hiding of UB in transpiled code, and it was not used at all in languages other than C/C++ -- specifically when the C/C++ source files were created by transpiling from vala or cython.
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/cc @thesamesam |
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Looks pretty good to me. I agree that Vala needs to get with the times. |
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This was originally added for vala only, with the rationale that vala generates bad code that has warnings. Unfortunately, the rationale was fatally flawed. The compiler warns about a number of things, which the user can control depending on their code (or their code generator's code), but some of those things are absolutely critical to warn about.
In particular, GCC 14 and clang 17 are updating their defaults to warn -- and error by default for -- invalid C code that breaks the standard, but has been silently accepted for over 20 years "because lots of people do it". The code in question is UB, and compilers will generate faulty machine code that behaves erroneously and probably has a mass of CVEs waiting to happen.
Compiler warnings are NOT safe to just... universally turn off. Compiler warnings could be either:
There is no magic bullet to ignore the former while respecting the latter. And the very last thing we should ever do is pass
-w, since that causes ALL warnings to be disabled, even the manually added-Werror=XXX.If vala generated code creates warnings, then the vala compiler can decrease the log level by generating better code, or by adding warning suppression pragmas for specific issues, such as unused functions.