Minor.

backends.py

@@ -242,7 +242,7 @@ class Backend():
                     unity_src.append(abs_src)
                 else:
                     obj_list.append(self.generate_single_compile(target, outfile, src, False, header_deps))
-        obj_list += self.flatten_obj_list(target)
+        obj_list += self.flatten_object_list(target)
         if is_unity:
             for src in self.generate_unity_files(target, unity_src):
                 obj_list.append(self.generate_single_compile(target, outfile, src, True, unity_deps + header_deps))
@@ -938,9 +938,6 @@ class NinjaBackend(Backend):
                 if len(infilelist) == len(outfilelist):
                     sole_output = os.path.join(self.get_target_private_dir(target), outfilelist[i])
                 else:
-                    for x in base_args:
-                        if '@OUTPUT@' in x:
-                            raise MesonException('Tried to use @OUTPUT@ in a rule with more than one output.')
                     sole_output = ''
                 curfile = infilelist[i]
                 infilename = os.path.join(self.environment.get_source_dir(), curfile)

build.py

@@ -387,7 +387,7 @@ class Generator():
     def __init__(self, args, kwargs):
         if len(args) != 1:
             raise InvalidArguments('Generator requires one and only one positional argument')
-        
+
         if hasattr(args[0], 'held_object'):
             exe = args[0].held_object
             if not isinstance(exe, Executable):
@@ -427,6 +427,10 @@ class Generator():
                 raise InvalidArguments('"outputs" must contain @BASENAME@ or @PLAINNAME@.')
             if '/' in rule or '\\' in rule:
                 raise InvalidArguments('"outputs" must not contain a directory separator.')
+        if len(outputs) > 1:
+            for o in outputs:
+                if '@OUTPUT@' in o:
+                    raise InvalidArguments('Tried to use @OUTPUT@ in a rule with more than one output.')
         self.outputs = outputs
 
     def get_base_outnames(self, inname):

test cases/common/29 pipeline/meson.build

@@ -4,6 +4,7 @@ project('pipeline test', 'c')
 # the host compiler.
 e1 = executable('srcgen', 'srcgen.c', native : true)
 
+# Generate a source file that needs to be included in the build.
 gen = generator(e1, \
  outputs  : '@BASENAME@.c', # Line continuation inside arguments should work without needing a "\".
  arguments : ['@INPUT@', '@OUTPUT@'])

test cases/common/30 pipeline/meson.build

@@ -2,6 +2,7 @@ project('pipeline test', 'c')
 
 e1 = executable('srcgen', 'srcgen.c', native : true)
 
+# Generate a header file that needs to be included.
 gen = generator(e1,
  outputs  : '@BASENAME@.h',
  arguments : ['@INPUT@', '@OUTPUT@'])