Fix an issue where the future import should be first.

parso/python/normalizer.py

@@ -15,10 +15,43 @@ class CompressNormalizer(Normalizer):
         return leaf.prefix + leaf.value
 
 
-def is_future_import(from_import):
-    from_names = from_import.get_from_names()
+def _iter_stmts(scope):
+    """
+    Iterates over all statements and splits up  simple_stmt.
+    """
+    for child in scope.children:
+        if child.type == 'simple_stmt':
+            for child2 in child.children:
+                if child2.type == 'newline' or child2 == ';':
+                    continue
+                yield child2
+        else:
+            yield child
+
+
+def _is_future_import(import_from):
+    if import_from.level != 0:
+        return False
+    from_names = import_from.get_from_names()
     return [n.value for n in from_names] == ['__future__']
 
+
+def _is_future_import_first(import_from):
+    """
+    Checks if the import is the first statement of a file.
+    """
+    found_docstring = False
+    for stmt in _iter_stmts(import_from.get_root_node()):
+        if stmt == import_from:
+            return True
+        if stmt.type == 'import_from' and _is_future_import(stmt):
+            continue
+        if stmt.type == 'string' and not found_docstring:
+            found_docstring = True
+            continue
+        return False
+
+
 class Context(object):
     def __init__(self, node, parent_context=None):
         self.node = node
@@ -92,8 +125,8 @@ class ErrorFinder(Normalizer):
                 yield
                 self._context = context
             return
-        elif node.type == 'import_from' and node.level == 0 \
-                and is_future_import(node):
+        elif node.type == 'import_from' \
+                and _is_future_import(node) and not _is_future_import_first(node):
             message = "from __future__ imports must occur at the beginning of the file"
             self._add_syntax_error(message, node)
         elif node.type in _STAR_EXPR_PARENTS:

test/test_python_errors.py

@@ -10,8 +10,7 @@ import parso
 from parso.python.normalizer import ErrorFinderConfig
 
 def _get_error_list(code, version=None):
-    grammar = parso.load_grammar(version=version)
-    tree = grammar.parse(code)
+    tree = parso.parse(code, version=version)
     config = ErrorFinderConfig()
     return list(tree._get_normalizer_issues(config))
 
@@ -148,3 +147,26 @@ def test_statically_nested_blocks():
 
     assert get_error(20)
     assert get_error(20, add_func=True)
+
+
+def test_future_import_first():
+    def is_issue(code, *args):
+        code = code % args
+        return bool(_get_error_list(code))
+
+    i1 = 'from __future__ import division'
+    i2 = 'from __future__ import absolute_import'
+    assert not is_issue(i1)
+    assert not is_issue(i1 + ';' + i2)
+    assert not is_issue(i1 + '\n' + i2)
+    assert not is_issue('"";' + i1)
+    assert not is_issue('"";' + i1)
+    assert not is_issue('""\n' + i1)
+    assert not is_issue('""\n%s\n%s', i1, i2)
+    assert not is_issue('""\n%s;%s', i1, i2)
+    assert not is_issue('"";%s;%s ', i1, i2)
+    assert not is_issue('"";%s\n%s ', i1, i2)
+    assert is_issue('1;' + i1)
+    assert is_issue('1\n' + i1)
+    assert is_issue('"";1\n' + i1)
+    assert is_issue('""\n%s\nfrom x import a\n%s', i1, i2)