ast/interpreter, rewriter: make flatten_args() recursive

This also enables using it instead of flatten().

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

mesonbuild/ast/interpreter.py

@@ -30,8 +30,6 @@ from ..interpreterbase import (
     InterpreterObject,
 )
 
-from ..interpreterbase.helpers import flatten
-
 from ..interpreter import (
     StringHolder,
     BooleanHolder,
@@ -723,7 +721,7 @@ class AstInterpreter(InterpreterBase):
             else:
                 raise TypeError
 
-        rtvals: T.List[T.Any] = flatten([self.node_to_runtime_value(sn) for sn in nodes])
+        rtvals: T.List[T.Any] = self.flatten_args(nodes)
         return [src_to_abs(x) for x in rtvals]
 
     def flatten_args(self, args: T.Sequence[TYPE_nvar]) -> T.List[TYPE_var]:
@@ -737,10 +735,12 @@ class AstInterpreter(InterpreterBase):
                 if resolved is not None:
                     if not isinstance(resolved, list):
                         resolved = [resolved]
-                    flattened_args += resolved
+                    flattened_args += self.flatten_args(resolved)
             elif isinstance(i, (str, bool, int, float, dict, UnknownValue, IntrospectionFile,
                                 IntrospectionBuildTarget, IntrospectionDependency)):
                 flattened_args += [i]
+            elif isinstance(i, list):
+                flattened_args += self.flatten_args(i)
             else:
                 raise NotImplementedError(f'flatten_args is missing a case for {type(i)}')
         return flattened_args

mesonbuild/rewriter.py

@@ -12,7 +12,6 @@ from __future__ import annotations
 from .ast import IntrospectionInterpreter, BUILD_TARGET_FUNCTIONS, AstConditionLevel, AstIDGenerator, AstIndentationGenerator, AstPrinter
 from .ast.interpreter import IntrospectionBuildTarget, IntrospectionDependency, _symbol
 from .interpreterbase import UnknownValue
-from .interpreterbase.helpers import flatten
 from mesonbuild.mesonlib import MesonException, pathname_sort_key, relpath, setup_vsenv
 from . import mlog, environment
 from functools import wraps
@@ -758,7 +757,7 @@ class Rewriter:
             tgt_function.args.kwargs[extra_files_idnode] = new_extra_files_node
 
         newfiles_relto = self.get_relto(target.node, chosen)
-        old_src_list: T.List[T.Any] = flatten([self.interpreter.node_to_runtime_value(sn) for sn in old])
+        old_src_list: T.List[T.Any] = self.interpreter.flatten_args(list(old))
 
         if op == 'src_add':
             name = 'Source'

test cases/rewrite/8 kwargs dict/meson.build

@@ -8,3 +8,6 @@ project(
 )
 
 dep1 = dependency('zlib', required: false, default_options: {'foo': 'bar'})
+
+# a dict can also be a positional argument; it must not be flattened away
+conf = configuration_data({'foo': 'bar'})