qt module: allow has_tools to specify which tools to check

This allows checking for tools that may not be available in older version of qt
or avoiding requesting tools that may not be necessary for a given project

Co-authored-by: Nirbheek Chauhan <nirbheek@centricular.com>

docs/markdown/Qt6-module.md

@@ -156,6 +156,9 @@ This method takes the following keyword arguments:
   `true` or an enabled [`feature`](Build-options.md#features) and some tools are
   missing Meson will abort.
 - `method` string: The method to use to detect Qt, see [[dependency]]
+- `tools`: string[]: *Since 1.6.0*. List of tools to check. Testable tools
+  are `moc`, `uic`, `rcc` and `lrelease`. By default `tools` is set to `['moc',
+  'uic', 'rcc', 'lrelease']`
 
 ## Dependencies
 

docs/markdown/snippets/qt_has_tools_ignore.md

@@ -0,0 +1,12 @@
+## Tools can be selected when calling `has_tools()` on the Qt modules
+
+When checking for the presence of Qt tools, you can now explictly ask Meson
+which tools you need. This is particularly useful when you do not need
+`lrelease` because you are not shipping any translations. For example:
+
+```meson
+qt6_mod = import('qt6')
+qt6_mod.has_tools(required: true, tools: ['moc', 'uic', 'rcc'])
+```
+
+valid tools are `moc`, `uic`, `rcc` and `lrelease`.

mesonbuild/modules/_qt.py

@@ -27,6 +27,7 @@ if T.TYPE_CHECKING:
     from ..interpreter import kwargs
     from ..mesonlib import FileOrString
     from ..programs import ExternalProgram
+    from typing_extensions import Literal
 
     QtDependencyType = T.Union[QtPkgConfigDependency, QmakeQtDependency]
 
@@ -80,6 +81,7 @@ if T.TYPE_CHECKING:
     class HasToolKwArgs(kwargs.ExtractRequired):
 
         method: str
+        tools: T.List[Literal['moc', 'uic', 'rcc', 'lrelease']]
 
     class CompileTranslationsKwArgs(TypedDict):
 
@@ -91,10 +93,21 @@ if T.TYPE_CHECKING:
         rcc_extra_arguments: T.List[str]
         ts_files: T.List[T.Union[str, File, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList]]
 
+def _list_in_set_validator(choices: T.Set[str]) -> T.Callable[[T.List[str]], T.Optional[str]]:
+    """Check that the choice given was one of the given set."""
+    def inner(checklist: T.List[str]) -> T.Optional[str]:
+        invalid = set(checklist).difference(choices)
+        if invalid:
+            return f"invalid selections {', '.join(sorted(invalid))}, valid elements are {', '.join(sorted(choices))}."
+        return None
+
+    return inner
+
 class QtBaseModule(ExtensionModule):
     _tools_detected = False
     _rcc_supports_depfiles = False
     _moc_supports_depfiles = False
+    _set_of_qt_tools = {'moc', 'uic', 'rcc', 'lrelease'}
 
     def __init__(self, interpreter: 'Interpreter', qt_version: int = 5):
         ExtensionModule.__init__(self, interpreter)
@@ -102,10 +115,7 @@ class QtBaseModule(ExtensionModule):
         # It is important that this list does not change order as the order of
         # the returned ExternalPrograms will change as well
         self.tools: T.Dict[str, T.Union[ExternalProgram, build.Executable]] = {
-            'moc': NonExistingExternalProgram('moc'),
-            'uic': NonExistingExternalProgram('uic'),
-            'rcc': NonExistingExternalProgram('rcc'),
-            'lrelease': NonExistingExternalProgram('lrelease'),
+            tool: NonExistingExternalProgram(tool) for tool in self._set_of_qt_tools
         }
         self.methods.update({
             'has_tools': self.has_tools,
@@ -258,6 +268,10 @@ class QtBaseModule(ExtensionModule):
         'qt.has_tools',
         KwargInfo('required', (bool, options.UserFeatureOption), default=False),
         KwargInfo('method', str, default='auto'),
+        KwargInfo('tools', ContainerTypeInfo(list, str), listify=True,
+                  default=['moc', 'uic', 'rcc', 'lrelease'],
+                  validator=_list_in_set_validator(_set_of_qt_tools),
+                  since='1.6.0'),
     )
     def has_tools(self, state: 'ModuleState', args: T.Tuple, kwargs: 'HasToolKwArgs') -> bool:
         method = kwargs.get('method', 'auto')
@@ -269,8 +283,9 @@ class QtBaseModule(ExtensionModule):
             mlog.log('qt.has_tools skipped: feature', mlog.bold(feature), 'disabled')
             return False
         self._detect_tools(state, method, required=False)
-        for tool in self.tools.values():
-            if not tool.found():
+        for tool in kwargs['tools']:
+            assert tool in self._set_of_qt_tools, f'tools must be in {self._set_of_qt_tools}'
+            if not self.tools[tool].found():
                 if required:
                     raise MesonException('Qt tools not found')
                 return False

test cases/frameworks/4 qt/meson.build

@@ -48,7 +48,13 @@ foreach qt : ['qt4', 'qt5', 'qt6']
   qtdep = dependency(qt, modules : qt_modules, main : true, private_headers: true, required : required, method : get_option('method'))
   if qtdep.found()
     qtmodule = import(qt)
-    assert(qtmodule.has_tools(), 'You may be missing a devel package. (qttools5-dev-tools on Debian based systems)')
+    if get_option('expect_lrelease')
+      assert(qtmodule.has_tools(), 'You may be missing a devel package. (qttools5-dev-tools on Debian based systems)')
+    else
+      assert(not qtmodule.has_tools(), 'Unexpectedly found lrelease')
+      assert(not qtmodule.has_tools(tools: ['lrelease']), 'Unexpectedly found lrelease')
+      assert(qtmodule.has_tools(tools: ['moc', 'uic', 'rcc']), 'You may be missing a devel package. (qttools5-dev-tools on Debian based systems)')
+    endif
 
     # Test that fetching a variable works and yields a non-empty value
     assert(qtdep.get_variable('prefix', configtool: 'QT_INSTALL_PREFIX') != '')
@@ -91,23 +97,25 @@ foreach qt : ['qt4', 'qt5', 'qt6']
     # qt4-rcc and qt5-rcc take different arguments, for example qt4: ['-compress', '3']; qt5: '--compress=3'
     qtmodule.preprocess(qt + 'testrccarg', qresources : files(['stuff.qrc', 'stuff2.qrc']), rcc_extra_arguments : '--compress=3', method : get_option('method'))
 
-    translations_cpp = qtmodule.compile_translations(qresource: qt+'_lang.qrc')
-    # unity builds suck and definitely cannot handle two qrc embeds in one compilation unit
-    unityproof_translations = static_library(qt+'unityproof_translations', translations_cpp, dependencies: qtdep)
+    if get_option('expect_lrelease')
+      translations_cpp = qtmodule.compile_translations(qresource: qt+'_lang.qrc')
+      # unity builds suck and definitely cannot handle two qrc embeds in one compilation unit
+      unityproof_translations = static_library(qt+'unityproof_translations', translations_cpp, dependencies: qtdep)
 
-    extra_cpp_args += '-DQT="@0@"'.format(qt)
-    qexe = executable(qt + 'app',
-      sources : ['main.cpp', 'mainWindow.cpp', # Sources that don't need preprocessing.
-      prep, prep_rcc],
-      dependencies : qtdep,
-      link_with: unityproof_translations,
-      cpp_args: extra_cpp_args,
-      gui_app : true)
+      extra_cpp_args += '-DQT="@0@"'.format(qt)
+      qexe = executable(qt + 'app',
+        sources : ['main.cpp', 'mainWindow.cpp', # Sources that don't need preprocessing.
+        prep, prep_rcc],
+        dependencies : qtdep,
+        link_with: unityproof_translations,
+        cpp_args: extra_cpp_args,
+        gui_app : true)
 
-    # We need a console test application because some test environments
-    # do not have an X server.
+      # We need a console test application because some test environments
+      # do not have an X server.
 
-    translations = qtmodule.compile_translations(ts_files : qt+'core_fr.ts', build_by_default : true)
+      translations = qtmodule.compile_translations(ts_files : qt+'core_fr.ts', build_by_default : true)
+    endif
 
     qtcore = dependency(qt, modules : 'Core', method : get_option('method'))
 

test cases/frameworks/4 qt/meson_options.txt

@@ -1,2 +1,3 @@
 option('method', type : 'string', value : 'auto', description : 'The method to use to find Qt')
 option('required', type : 'string', value : 'qt5', description : 'The version of Qt which is required to be present')
+option('expect_lrelease', type: 'boolean', value: true)

unittests/linuxliketests.py

@@ -36,6 +36,7 @@ from mesonbuild.compilers.cpp import AppleClangCPPCompiler
 from mesonbuild.compilers.objc import AppleClangObjCCompiler
 from mesonbuild.compilers.objcpp import AppleClangObjCPPCompiler
 from mesonbuild.dependencies.pkgconfig import PkgConfigDependency, PkgConfigCLI, PkgConfigInterface
+from mesonbuild.programs import NonExistingExternalProgram
 import mesonbuild.modules.pkgconfig
 
 PKG_CONFIG = os.environ.get('PKG_CONFIG', 'pkg-config')
@@ -317,6 +318,19 @@ class LinuxlikeTests(BasePlatformTests):
         self.init(testdir, extra_args=['-Db_sanitize=address', '-Db_lundef=false'])
         self.build()
 
+    def test_qt5dependency_no_lrelease(self):
+        '''
+        Test that qt5 detection with qmake works. This can't be an ordinary
+        test case because it involves setting the environment.
+        '''
+        testdir = os.path.join(self.framework_test_dir, '4 qt')
+        def _no_lrelease(self, prog, *args, **kwargs):
+            if 'lrelease' in prog:
+                return NonExistingExternalProgram(prog)
+            return self._interpreter.find_program_impl(prog, *args, **kwargs)
+        with mock.patch.object(mesonbuild.modules.ModuleState, 'find_program', _no_lrelease):
+            self.init(testdir, inprocess=True, extra_args=['-Dmethod=qmake', '-Dexpect_lrelease=false'])
+
     def test_qt5dependency_qmake_detection(self):
         '''
         Test that qt5 detection with qmake works. This can't be an ordinary