Interpreter: don't flatten the arguments of various methods

this fixes eg set_variable('foo', ['bar', 'baz']), which
was previously erroring out complaining about the number
of arguments.

Closes #1481

mesonbuild/interpreter.py

@@ -25,7 +25,7 @@ from .mesonlib import FileMode, Popen_safe, listify, extract_as_list, has_path_s
 from .dependencies import ExternalProgram
 from .dependencies import InternalDependency, Dependency, NotFoundDependency, DependencyException
 from .interpreterbase import InterpreterBase
-from .interpreterbase import check_stringlist, noPosargs, noKwargs, stringArgs, permittedKwargs, permittedMethodKwargs
+from .interpreterbase import check_stringlist, flatten, noPosargs, noKwargs, stringArgs, permittedKwargs, permittedMethodKwargs, noArgsFlattening
 from .interpreterbase import InterpreterException, InvalidArguments, InvalidCode, SubdirDoneRequest
 from .interpreterbase import InterpreterObject, MutableInterpreterObject, Disabler
 from .modules import ModuleReturnValue
@@ -202,6 +202,7 @@ class ConfigurationDataHolder(MutableInterpreterObject, ObjectHolder):
 
         return name, val, desc
 
+    @noArgsFlattening
     def set_method(self, args, kwargs):
         (name, val, desc) = self.validate_args(args, kwargs)
         self.held_object.values[name] = (val, desc)
@@ -223,6 +224,7 @@ class ConfigurationDataHolder(MutableInterpreterObject, ObjectHolder):
     def has_method(self, args, kwargs):
         return args[0] in self.held_object.values
 
+    @noArgsFlattening
     def get_method(self, args, kwargs):
         if len(args) < 1 or len(args) > 2:
             raise InterpreterException('Get method takes one or two arguments.')
@@ -1309,6 +1311,8 @@ class ModuleHolder(InterpreterObject, ObjectHolder):
             raise InvalidArguments('Module %s does not have method %s.' % (self.modname, method_name))
         if method_name.startswith('_'):
             raise InvalidArguments('Function {!r} in module {!r} is private.'.format(method_name, self.modname))
+        if not getattr(fn, 'no-args-flattening', False):
+            args = flatten(args)
         # This is not 100% reliable but we can't use hash()
         # because the Build object contains dicts and lists.
         num_targets = len(self.interpreter.build.targets)
@@ -1507,6 +1511,7 @@ class MesonMain(InterpreterObject):
     def project_name_method(self, args, kwargs):
         return self.interpreter.active_projectname
 
+    @noArgsFlattening
     def get_cross_property_method(self, args, kwargs):
         if len(args) < 1 or len(args) > 2:
             raise InterpreterException('Must have one or two arguments.')
@@ -3505,6 +3510,7 @@ This will become a hard error in the future.''')
         return self.subproject != ''
 
     @noKwargs
+    @noArgsFlattening
     def func_set_variable(self, node, args, kwargs):
         if len(args) != 2:
             raise InvalidCode('Set_variable takes two arguments.')
@@ -3513,6 +3519,7 @@ This will become a hard error in the future.''')
         self.set_variable(varname, value)
 
     @noKwargs
+    @noArgsFlattening
     def func_get_variable(self, node, args, kwargs):
         if len(args) < 1 or len(args) > 2:
             raise InvalidCode('Get_variable takes one or two arguments.')

mesonbuild/interpreterbase.py

@@ -31,6 +31,22 @@ def check_stringlist(a, msg='Arguments must be strings.'):
         mlog.debug('Element not a string:', str(a))
         raise InvalidArguments(msg)
 
+def flatten(args):
+    if isinstance(args, mparser.StringNode):
+        return args.value
+    if isinstance(args, (int, str, mesonlib.File, InterpreterObject)):
+        return args
+    result = []
+    for a in args:
+        if isinstance(a, list):
+            rest = flatten(a)
+            result = result + rest
+        elif isinstance(a, mparser.StringNode):
+            result.append(a.value)
+        else:
+            result.append(a)
+    return result
+
 def noPosargs(f):
     @wraps(f)
     def wrapped(self, node, args, kwargs):
@@ -55,6 +71,10 @@ def stringArgs(f):
         return f(self, node, args, kwargs)
     return wrapped
 
+def noArgsFlattening(f):
+    setattr(f, 'no-args-flattening', True)
+    return f
+
 class permittedKwargs:
 
     def __init__(self, permitted):
@@ -114,7 +134,10 @@ class InterpreterObject:
 
     def method_call(self, method_name, args, kwargs):
         if method_name in self.methods:
-            return self.methods[method_name](args, kwargs)
+            method = self.methods[method_name]
+            if not getattr(method, 'no-args-flattening', False):
+                args = flatten(args)
+            return method(args, kwargs)
         raise InvalidCode('Unknown method "%s" in object.' % method_name)
 
 class MutableInterpreterObject(InterpreterObject):
@@ -474,7 +497,11 @@ The result of this is undefined and will become a hard error in a future Meson r
         if is_disabled(posargs, kwargs):
             return Disabler()
         if func_name in self.funcs:
-            return self.funcs[func_name](node, self.flatten(posargs), kwargs)
+            func = self.funcs[func_name]
+            if not getattr(func, 'no-args-flattening', False):
+                posargs = flatten(posargs)
+
+            return func(node, posargs, kwargs)
         else:
             self.unknown_function_called(func_name)
 
@@ -508,7 +535,7 @@ The result of this is undefined and will become a hard error in a future Meson r
             return Disabler()
         if method_name == 'extract_objects':
             self.validate_extraction(obj.held_object)
-        return obj.method_call(method_name, self.flatten(args), kwargs)
+        return obj.method_call(method_name, args, kwargs)
 
     def bool_method_call(self, obj, method_name, args):
         (posargs, kwargs) = self.reduce_arguments(args)
@@ -668,22 +695,6 @@ The result of this is undefined and will become a hard error in a future Meson r
         self.argument_depth -= 1
         return reduced_pos, reduced_kw
 
-    def flatten(self, args):
-        if isinstance(args, mparser.StringNode):
-            return args.value
-        if isinstance(args, (int, str, mesonlib.File, InterpreterObject)):
-            return args
-        result = []
-        for a in args:
-            if isinstance(a, list):
-                rest = self.flatten(a)
-                result = result + rest
-            elif isinstance(a, mparser.StringNode):
-                result.append(a.value)
-            else:
-                result.append(a)
-        return result
-
     def assignment(self, node):
         assert(isinstance(node, mparser.AssignmentNode))
         if self.argument_depth != 0:

mesonbuild/modules/python.py

@@ -25,6 +25,7 @@ from ..interpreterbase import (
     InterpreterObject, InvalidArguments
 )
 from ..interpreter import ExternalProgramHolder
+from ..interpreterbase import flatten
 from ..build import known_shmod_kwargs
 from .. import mlog
 from ..environment import detect_cpu_family
@@ -415,6 +416,9 @@ class PythonInstallation(ExternalProgramHolder, InterpreterObject):
         except AttributeError:
             raise InvalidArguments('Python object does not have method %s.' % method_name)
 
+        if not getattr(fn, 'no-args-flattening', False):
+            args = flatten(args)
+
         if method_name in ['extension_module', 'dependency', 'install_sources']:
             value = fn(self.interpreter, None, args, kwargs)
             return self.interpreter.holderify(value)

mesonbuild/modules/unstable_icestorm.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from .. import mesonlib
+from ..interpreterbase import flatten
 
 from . import ExtensionModule
 
@@ -42,7 +43,7 @@ class IceStormModule(ExtensionModule):
         kwarg_sources = kwargs.get('sources', [])
         if not isinstance(kwarg_sources, list):
             kwarg_sources = [kwarg_sources]
-        all_sources = interpreter.source_strings_to_files(interpreter.flatten(arg_sources + kwarg_sources))
+        all_sources = interpreter.source_strings_to_files(flatten(arg_sources + kwarg_sources))
         if 'constraint_file' not in kwargs:
             raise mesonlib.MesonException('Constraint file not specified.')
 

test cases/common/198 args flattening/meson.build

@@ -0,0 +1,23 @@
+project('args flattening')
+
+arr = get_variable('does-not-exist', ['bar', 'baz'])
+
+assert(arr == ['bar', 'baz'], 'get_variable with array fallback is broken')
+
+set_variable('arr', ['bar', 'baz'])
+
+assert(arr == ['bar', 'baz'], 'set_variable(array) is broken')
+
+conf = configuration_data()
+
+conf.set('foo', ['bar', 'baz'])
+
+assert(conf.get('foo') == ['bar', 'baz'], 'configuration_data.set(array) is broken')
+
+arr = conf.get('does-not-exist', ['bar', 'baz'])
+
+assert(arr == ['bar', 'baz'], 'configuration_data.get with array fallback is broken')
+
+arr = meson.get_cross_property('does-not-exist', ['bar', 'baz'])
+
+assert(arr == ['bar', 'baz'], 'meson.get_cross_property with array fallback is broken')