Enforce `state='file'` in `copy` module

This was causing wrong behaviour when `prev_state` was `hard`-link,
since the `file` module tried to apply the same `state` on the new
file, causing unexpected errors.

Particularly, both `overlay` and `devicemapper` storage drivers in
docker use hardlinks to share files between layers. This causes
most ansible playbooks to fail when working with files from layers
below.

lib/ansible/modules/files/file.py

@@ -250,6 +250,7 @@ def main():
         if basename:
             params['path'] = path = os.path.join(path, basename)
             b_path = to_bytes(path, errors='surrogate_or_strict')
+            prev_state = get_state(b_path)
 
     # make sure the target path is a directory when we're doing a recursive operation
     if recurse and state != 'directory':

lib/ansible/plugins/action/copy.py

@@ -331,7 +331,8 @@ class ActionModule(ActionBase):
                 dict(
                     src=source_rel,
                     dest=dest,
-                    original_basename=source_rel
+                    original_basename=source_rel,
+                    state='file',
                 )
             )
             if lmode:

test/integration/targets/copy/tasks/tests.yml

@@ -156,6 +156,18 @@
        - "stat_results.stat.checksum == ('modified'|hash('sha1'))"
        - "stat_results.stat.mode == '0700'"
 
+- name: Create a hardlink to the file
+  file:
+    src: '{{ remote_file }}'
+    dest: '{{ output_dir }}/hard.lnk'
+    state: hard
+
+- name: copy the same contents into place
+  copy:
+    content: 'modified'
+    dest: '{{ remote_file }}'
+    mode: 0404
+
 - name: Try invalid copy input location fails
   copy:
     src: invalid_file_location_does_not_exist
@@ -1072,6 +1084,34 @@
        - "stat_results.stat.checksum == ('modified'|hash('sha1'))"
        - "not stat_results.stat.islnk"
 
+- name: setup directory for test
+  file: state=directory dest={{remote_dir }}/directory mode=0755
+
+- name: set file mode when the destination is a directory
+  copy: src=foo.txt dest={{remote_dir}}/directory/ mode=0705
+
+- name: set file mode when the destination is a directory
+  copy: src=foo.txt dest={{remote_dir}}/directory/ mode=0604
+  register: file_result
+
+- name: check that the file has the correct attributes
+  stat: path={{ remote_dir }}/directory/foo.txt
+  register: file_attrs
+
+- assert:
+    that:
+      - "file_attrs.stat.uid == 0"
+      - "file_attrs.stat.pw_name == 'root'"
+      - "file_attrs.stat.mode == '0604'"
+
+- name: check that the containing directory did not change attributes
+  stat: path={{ remote_dir }}/directory/
+  register: dir_attrs
+
+- assert:
+    that:
+      - "dir_attrs.stat.mode == '0755'"
+
 #
 # I believe the below section is now covered in the recursive copying section.
 # Hold on for now as an original test case but delete once confirmed that