Add 'disabler' argument to functions returning not-found objects

When dependency(), find_library(), find_program(), or
python.find_installation() return a not-found object and disabler is
true, they return a Disabler object instead.

3 files changed, 21 insertions, 2 deletions

diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 98424ec..66f7f02 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -27,7 +27,7 @@ from .dependencies import InternalDependency, Dependency, NotFoundDependency, De
 from .interpreterbase import InterpreterBase
 from .interpreterbase import check_stringlist, flatten, noPosargs, noKwargs, stringArgs, permittedKwargs, noArgsFlattening
 from .interpreterbase import InterpreterException, InvalidArguments, InvalidCode, SubdirDoneRequest
-from .interpreterbase import InterpreterObject, MutableInterpreterObject, Disabler
+from .interpreterbase import InterpreterObject, MutableInterpreterObject, Disabler, disablerIfNotFound
 from .interpreterbase import FeatureNew, FeatureDeprecated, FeatureNewKwargs
 from .interpreterbase import ObjectHolder
 from .modules import ModuleReturnValue
@@ -1381,6 +1381,8 @@ class CompilerHolder(InterpreterObject):
         mlog.log('Header <{0}> has symbol "{1}":'.format(hname, symbol), h)
         return haz
 
+    @FeatureNewKwargs('compiler.find_library', '0.49.0', ['disabler'])
+    @disablerIfNotFound
     @permittedKwargs({
         'required',
         'dirs',
@@ -2776,6 +2778,8 @@ external dependencies (including libraries) must go to "dependencies".''')
         self.store_name_lookups(args)
         return progobj
 
+    @FeatureNewKwargs('find_program', '0.49.0', ['disabler'])
+    @disablerIfNotFound
     @permittedKwargs(permitted_kwargs['find_program'])
     def func_find_program(self, node, args, kwargs):
         if not args:
@@ -2902,8 +2906,10 @@ external dependencies (including libraries) must go to "dependencies".''')
         elif name == 'openmp':
             FeatureNew('OpenMP Dependency', '0.46.0').use(self.subproject)
 
+    @FeatureNewKwargs('dependency', '0.49.0', ['disabler'])
     @FeatureNewKwargs('dependency', '0.40.0', ['method'])
     @FeatureNewKwargs('dependency', '0.38.0', ['default_options'])
+    @disablerIfNotFound
     @permittedKwargs(permitted_kwargs['dependency'])
     def func_dependency(self, node, args, kwargs):
         self.validate_arguments(args, 1, [str])
diff --git a/mesonbuild/interpreterbase.py b/mesonbuild/interpreterbase.py
index c0064ab..aee1c87 100644
--- a/mesonbuild/interpreterbase.py
+++ b/mesonbuild/interpreterbase.py
@@ -145,6 +145,17 @@ def noArgsFlattening(f):
     setattr(f, 'no-args-flattening', True)
     return f
 
+def disablerIfNotFound(f):
+    @wraps(f)
+    def wrapped(*wrapped_args, **wrapped_kwargs):
+        kwargs = _get_callee_args(wrapped_args)[3]
+        disabler = kwargs.pop('disabler', False)
+        ret = f(*wrapped_args, **wrapped_kwargs)
+        if disabler and not ret.held_object.found():
+            return Disabler()
+        return ret
+    return wrapped
+
 class permittedKwargs:
 
     def __init__(self, permitted):
diff --git a/mesonbuild/modules/python.py b/mesonbuild/modules/python.py
index 2229949..954220b 100644
--- a/mesonbuild/modules/python.py
+++ b/mesonbuild/modules/python.py
@@ -23,7 +23,7 @@ from mesonbuild.modules import ModuleReturnValue
 from ..interpreterbase import (
     noPosargs, noKwargs, permittedKwargs,
     InterpreterObject, InvalidArguments,
-    FeatureNew
+    FeatureNew, FeatureNewKwargs, disablerIfNotFound
 )
 from ..interpreter import ExternalProgramHolder, extract_required_kwarg
 from ..interpreterbase import flatten
@@ -467,6 +467,8 @@ class PythonModule(ExtensionModule):
             return mesonlib.version_compare(version, '>= 3.0')
         return True
 
+    @FeatureNewKwargs('python.find_installation', '0.49.0', ['disabler'])
+    @disablerIfNotFound
     @permittedKwargs(['required'])
     def find_installation(self, interpreter, state, args, kwargs):
         feature_check = FeatureNew('Passing "feature" option to find_installation', '0.48.0')