define QT_DEBUG or QT_NO_DEBUG depending on build type

to mimick what qmake does.

Fixes: #15059

Author: ggirol-rc

mesonbuild/dependencies/qt.py

@@ -166,6 +166,9 @@ def get_exe_args(self, compiler: 'Compiler') -> T.List[str]:
     def log_details(self) -> str:
         return f'modules: {", ".join(sorted(self.requested_modules))}'
 
+    def _get_common_defines(self) -> T.List[str]:
+        is_debug = self.env.coredata.optstore.get_value_for('debug')
+        return ['-DQT_DEBUG' if is_debug else '-DQT_NO_DEBUG']
 
 class QtPkgConfigDependency(_QtBase, PkgConfigDependency, metaclass=abc.ABCMeta):
 
@@ -225,6 +228,8 @@ def __init__(self, name: str, env: 'Environment', kwargs: T.Dict[str, T.Any]):
 
         self.libexecdir = self.get_pkgconfig_host_libexecs(self)
 
+        self.compile_args += self._get_common_defines()
+
     @staticmethod
     @abc.abstractmethod
     def get_pkgconfig_host_bins(core: PkgConfigDependency) -> T.Optional[str]:
@@ -268,6 +273,8 @@ def __init__(self, name: str, env: 'Environment', kwargs: T.Dict[str, T.Any]):
         if not self.found():
             return
 
+        self.compile_args += self._get_common_defines()
+
         # Query library path, header path, and binary path
         stdo = self.get_config_value(['-query'], 'args')
         qvars: T.Dict[str, str] = {}

test cases/frameworks/4 qt/assert_qt_debug.cpp

@@ -0,0 +1,5 @@
+#ifndef QT_DEBUG
+#error QT_DEBUG is not defined
+#endif
+
+int main() { return 0; }

test cases/frameworks/4 qt/assert_qt_no_debug.cpp

@@ -0,0 +1,5 @@
+#ifndef QT_NO_DEBUG
+#error QT_NO_DEBUG is not defined
+#endif
+
+int main() { return 0; }

test cases/frameworks/4 qt/meson.build

@@ -177,5 +177,12 @@ foreach qt : ['qt4', 'qt5', 'qt6']
     accept_versions = ['>=@0@'.format(qtdep.version()), '<@0@'.format(qtdep.version()[0].to_int() + 1)]
     dependency(qt, modules: qt_modules, version: accept_versions, method : get_option('method'))
 
+    # check that QT_DEBUG is correctly defined depending on whether this is a debug build
+    if get_option('debug')
+      assert_source = 'assert_qt_debug.cpp'
+    else
+      assert_source = 'assert_qt_no_debug.cpp'
+    endif
+    executable(qt + 'assert_debug', sources: [ assert_source ], dependencies: [ qtdep ])
   endif
 endforeach

test cases/frameworks/4 qt/test.json

@@ -5,6 +5,10 @@
         { "val": "config-tool" },
         { "val": "qmake" },
         { "val": "pkg-config" }
+      ],
+      "debug": [
+        { "val": "true" },
+        { "val": "false" }
       ]
     }
   },