Adding "follow" param for file/copy options

Also modifies the template action plugin to use this new param
when executing the file/copy modules for templating so that links
are preserved correctly.

Fixes #8998

test/integration/roles/test_copy/tasks/main.yml

@@ -207,3 +207,33 @@
 - name: clean up
   file: dest=/tmp/worldwritable state=absent
 
+# test overwritting a link using "follow=yes" so that the link
+# is preserved and the link target is updated
+
+- name: create a test file to symlink to
+  copy: dest={{output_dir}}/follow_test content="this is the follow test file\n"
+
+- name: create a symlink to the test file
+  file: path={{output_dir}}/follow_link src='./follow_test' state=link
+
+- name: update the test file using follow=True to preserve the link
+  copy: dest={{output_dir}}/follow_link content="this is the new content\n" follow=yes
+  register: replace_follow_result
+
+- name: stat the link path
+  stat: path={{output_dir}}/follow_link
+  register: stat_link_result
+
+- name: assert that the link is still a link
+  assert:
+    that:
+    - stat_link_result.stat.islnk
+
+- name: get the md5 of the link target
+  shell: md5sum {{output_dir}}/follow_test | cut -f1 -sd ' '
+  register: target_file_result
+
+- name: assert that the link target was updated
+  assert:
+    that:
+    - replace_follow_result.md5sum == target_file_result.stdout

test/integration/roles/test_file/tasks/main.yml

@@ -405,3 +405,29 @@
     that:
     - result.mode == '0444'
 
+# test the file module using follow=yes, so that the target of a
+# symlink is modified, rather than the link itself
+
+- name: create a test file
+  copy: dest={{output_dir}}/test_follow content="this is a test file\n" mode=0666
+
+- name: create a symlink to the test file
+  file: path={{output_dir}}/test_follow_link src="./test_follow" state=link
+
+- name: modify the permissions on the link using follow=yes
+  file: path={{output_dir}}/test_follow_link mode=0644 follow=yes
+  register: result
+
+- name: assert that the chmod worked
+  assert:
+    that:
+    - result.changed
+
+- name: stat the link target
+  stat: path={{output_dir}}/test_follow
+  register: result
+
+- name: assert that the link target was modified correctly
+  assert:
+    that:
+    - result.stat.mode == '0644'