Bug 1316844 - Make the linter detect unused dependencies. r=chmanchester

--HG--
extra : rebase_source : 44fea4820c95b5e0d274fa1b3bf6ce563af2c30a

python/mozbuild/mozbuild/configure/__init__.py

@@ -210,7 +210,7 @@ class ConfigureSandbox(dict):
         self._all_paths = set()
         self._templates = set()
         # Associate SandboxDependsFunctions to DependsFunctions.
-        self._depends = {}
+        self._depends = OrderedDict()
         self._seen = set()
         # Store the @imports added to a given function.
         self._imports = {}
@@ -388,6 +388,9 @@ class ConfigureSandbox(dict):
             raise KeyError('Cannot assign `%s` because it is neither a '
                            '@depends nor a @template' % key)
 
+        if isinstance(value, SandboxDependsFunction):
+            self._depends[value].func.__name__ = key
+
         return super(ConfigureSandbox, self).__setitem__(key, value)
 
     def _resolve(self, arg, need_help_dependency=True):

python/mozbuild/mozbuild/configure/lint.py

@@ -4,6 +4,7 @@
 
 from __future__ import absolute_import, print_function, unicode_literals
 
+import inspect
 from functools import wraps
 from StringIO import StringIO
 from . import (
@@ -32,6 +33,46 @@ class LintSandbox(ConfigureSandbox):
         if path:
             self.include_file(path)
 
+        for dep in self._depends.itervalues():
+            self._check_dependencies(dep)
+
+    def _check_dependencies(self, obj):
+        if isinstance(obj, CombinedDependsFunction) or obj in (self._always,
+                                                               self._never):
+            return
+        func, glob = self.unwrap(obj.func)
+        loc = '%s:%d' % (func.func_code.co_filename,
+                         func.func_code.co_firstlineno)
+        func_args = inspect.getargspec(func)
+        if func_args.keywords:
+            raise ConfigureError(
+                '%s: Keyword arguments are not allowed in @depends functions'
+                % loc
+            )
+
+        all_args = list(func_args.args)
+        if func_args.varargs:
+            all_args.append(func_args.varargs)
+        used_args = set()
+
+        for op, arg in disassemble_as_iter(func):
+            if op in ('LOAD_FAST', 'LOAD_CLOSURE'):
+                if arg in all_args:
+                    used_args.add(arg)
+
+        for num, arg in enumerate(all_args):
+            if arg not in used_args:
+                dep = obj.dependencies[num]
+                if dep != self._help_option:
+                    if isinstance(dep, DependsFunction):
+                        dep = dep.name
+                    else:
+                        dep = dep.option
+                    raise ConfigureError(
+                        '%s: The dependency on `%s` is unused.'
+                        % (loc, dep)
+                    )
+
     def _missing_help_dependency(self, obj):
         if isinstance(obj, CombinedDependsFunction):
             return False

python/mozbuild/mozbuild/test/configure/test_lint.py

@@ -44,7 +44,7 @@ class TestLint(unittest.TestCase):
 
             @depends('--help', foo)
             def bar(help, foo):
-                return
+                return foo
         '''):
             self.lint_test()
 
@@ -58,7 +58,7 @@ class TestLint(unittest.TestCase):
 
                 @depends('--help', foo)
                 def bar(help, foo):
-                    return
+                    return foo
             '''):
                 self.lint_test()
 
@@ -80,7 +80,7 @@ class TestLint(unittest.TestCase):
 
                     @depends('--help', foo)
                     def bar(help, foo):
-                        return
+                        return foo
                 tmpl()
             '''):
                 self.lint_test()
@@ -127,6 +127,73 @@ class TestLint(unittest.TestCase):
         '''):
             self.lint_test()
 
+        with self.assertRaises(ConfigureError) as e:
+            with self.moz_configure('''
+                option('--foo', help='foo')
+                @depends('--foo')
+                def foo(value):
+                    return
+
+                include(foo)
+            '''):
+                self.lint_test()
+
+        self.assertEquals(e.exception.message,
+                          "%s:3: The dependency on `--foo` is unused."
+                          % mozpath.join(test_data_path, 'moz.configure'))
+
+        with self.assertRaises(ConfigureError) as e:
+            with self.moz_configure('''
+                @depends(when=True)
+                def bar():
+                    return
+                @depends(bar)
+                def foo(value):
+                    return
+
+                include(foo)
+            '''):
+                self.lint_test()
+
+        self.assertEquals(e.exception.message,
+                          "%s:5: The dependency on `bar` is unused."
+                          % mozpath.join(test_data_path, 'moz.configure'))
+
+        with self.assertRaises(ConfigureError) as e:
+            with self.moz_configure('''
+                @depends(depends(when=True)(lambda: None))
+                def foo(value):
+                    return
+
+                include(foo)
+            '''):
+                self.lint_test()
+
+        self.assertEquals(e.exception.message,
+                          "%s:2: The dependency on `<lambda>` is unused."
+                          % mozpath.join(test_data_path, 'moz.configure'))
+
+        with self.assertRaises(ConfigureError) as e:
+            with self.moz_configure('''
+                @template
+                def tmpl():
+                    @depends(when=True)
+                    def bar():
+                        return
+                    return bar
+                qux = tmpl()
+                @depends(qux)
+                def foo(value):
+                    return
+
+                include(foo)
+            '''):
+                self.lint_test()
+
+        self.assertEquals(e.exception.message,
+                          "%s:9: The dependency on `qux` is unused."
+                          % mozpath.join(test_data_path, 'moz.configure'))
+
 
 if __name__ == '__main__':
     main()