ast: Make sure to avoid infinite recursions

2 files changed, 23 insertions, 9 deletions

diff --git a/mesonbuild/ast/interpreter.py b/mesonbuild/ast/interpreter.py
index bef1296..d0bbc69 100644
--- a/mesonbuild/ast/interpreter.py
+++ b/mesonbuild/ast/interpreter.py
@@ -244,12 +244,12 @@ class AstInterpreter(interpreterbase.InterpreterBase):
             self.reverse_assignment[node.value.ast_id] = node
         self.assign_vals[node.var_name] = [self.evaluate_statement(node.value)] # Evaluate the value just in case
 
-    def flatten_args(self, args: Any, include_unknown_args: bool = False) -> List[str]:
-        def quick_resolve(n: BaseNode) -> Any:
+    def flatten_args(self, args: Any, include_unknown_args: bool = False, id_loop_detect: List[str] = []) -> List[str]:
+        def quick_resolve(n: BaseNode, loop_detect: List[str] = []) -> Any:
             if isinstance(n, IdNode):
-                if n.value not in self.assignments:
+                if n.value in loop_detect or n.value not in self.assignments:
                     return []
-                return quick_resolve(self.assignments[n.value][0])
+                return quick_resolve(self.assignments[n.value][0], loop_detect = loop_detect + [n.value])
             elif isinstance(n, ElementaryNode):
                 return n.value
             else:
@@ -271,11 +271,11 @@ class AstInterpreter(interpreterbase.InterpreterBase):
             if isinstance(l, str) and isinstance(r, str):
                 args = [l + r] # String concatination detected
             else:
-                args = self.flatten_args(l) + self.flatten_args(r)
+                args = self.flatten_args(l, include_unknown_args, id_loop_detect) + self.flatten_args(r, include_unknown_args, id_loop_detect)
 
         elif isinstance(args, MethodNode):
             src = quick_resolve(args.source_object)
-            margs = self.flatten_args(args.args)
+            margs = self.flatten_args(args.args, include_unknown_args, id_loop_detect)
             try:
                 if isinstance(src, str):
                     args = [self.string_method_call(src, args.name, margs)]
@@ -298,10 +298,10 @@ class AstInterpreter(interpreterbase.InterpreterBase):
 
         # Resolve the contents of args
         for i in args:
-            if isinstance(i, IdNode):
-                flattend_args += self.flatten_args(quick_resolve(i), include_unknown_args)
+            if isinstance(i, IdNode) and i.value not in id_loop_detect:
+                flattend_args += self.flatten_args(quick_resolve(i), include_unknown_args, id_loop_detect + [i.value])
             elif isinstance(i, (ArrayNode, ArgumentNode, ArithmeticNode, MethodNode)):
-                flattend_args += self.flatten_args(i, include_unknown_args)
+                flattend_args += self.flatten_args(i, include_unknown_args, id_loop_detect)
             elif isinstance(i, mparser.ElementaryNode):
                 flattend_args += [i.value]
             elif isinstance(i, (str, bool, int, float)):
diff --git a/test cases/unit/55 introspection/meson.build b/test cases/unit/55 introspection/meson.build
index 7ee11a8..8ae00c2 100644
--- a/test cases/unit/55 introspection/meson.build
+++ b/test cases/unit/55 introspection/meson.build
@@ -28,6 +28,20 @@ t1 = executable('test' + var1, ['t1.cpp'], link_with: [sharedlib], install: true
 t2 = executable('test@0@'.format('@0@'.format(var2)), 't2.cpp', link_with: [staticlib])
 t3 = executable(var3, 't3.cpp', link_with: [sharedlib, staticlib], dependencies: [dep1])
 
+### BEGIN: Test stolen from taisei: https://github.com/taisei-project/taisei/blob/master/meson.build#L293
+have_posix = true
+systype = (have_posix ? 'POSIX (@0@)' : '@0@').format(host_machine.system())
+systype = '@0@, @1@, @2@'.format(systype, host_machine.cpu_family(), host_machine.cpu())
+systype = '@0@ (cross-compiling)'.format(systype)
+summary = '''
+
+Summary:
+    System type:            @0@
+'''.format(systype)
+
+message(summary)
+### END: Test stolen from taisei
+
 test('test case 1', t1)
 test('test case 2', t2)
 benchmark('benchmark 1', t3)