Fix dockerignore handling of absolute path exceptions.

Signed-off-by: mefyl <quentin.hocquet@docker.com>

2 files changed, 10 insertions, 3 deletions

diff --git a/docker/utils/build.py b/docker/utils/build.py
index d4223e7..e86a04e 100644
--- a/docker/utils/build.py
+++ b/docker/utils/build.py
@@ -26,13 +26,13 @@ def exclude_paths(root, patterns, dockerfile=None):
     if dockerfile is None:
         dockerfile = 'Dockerfile'
 
-    patterns = [p.lstrip('/') for p in patterns]
     exceptions = [p for p in patterns if p.startswith('!')]
 
-    include_patterns = [p[1:] for p in exceptions]
+    include_patterns = [p[1:].lstrip('/') for p in exceptions]
     include_patterns += [dockerfile, '.dockerignore']
 
-    exclude_patterns = list(set(patterns) - set(exceptions))
+    exclude_patterns = [
+        p.lstrip('/') for p in list(set(patterns) - set(exceptions))]
 
     paths = get_paths(root, exclude_patterns, include_patterns,
                       has_exceptions=len(exceptions) > 0)
diff --git a/tests/unit/utils_test.py b/tests/unit/utils_test.py
index eedcf71..0ee041a 100644
--- a/tests/unit/utils_test.py
+++ b/tests/unit/utils_test.py
@@ -758,6 +758,13 @@ class ExcludePathsTest(unittest.TestCase):
             self.all_paths - set(['foo/a.py'])
         )
 
+    def test_exclude_include_absolute_path(self):
+        base = make_tree([], ['a.py', 'b.py'])
+        assert exclude_paths(
+            base,
+            ['/*', '!/*.py']
+        ) == set(['a.py', 'b.py'])
+
     def test_single_subdir_with_path_traversal(self):
         assert self.exclude(['foo/whoops/../a.py']) == convert_paths(
             self.all_paths - set(['foo/a.py'])