From 8b0c46a51a33834d1eac7dc578197ea2eedcb712 Mon Sep 17 00:00:00 2001
From: Sam Doran <sdoran@redhat.com>
Date: Fri, 28 Sep 2018 16:04:50 -0400
Subject: [PATCH] Use bytes rather than native string for result (#46281)

This prevents a stack trace in Python 3 when the result is an empty file since
the file is open in binary mode and a native string in Python 3 is str,
not bytes.

(cherry picked from commit 8b1ae30e2ee86cdb8b68944b94846bbaf46228b4)
---
 .../fragments/blockinfile-bytes-fix.yaml      |  2 +
 lib/ansible/modules/files/blockinfile.py      |  2 +-
 .../targets/blockinfile/tasks/main.yml        | 93 ++++++++++++++-----
 3 files changed, 73 insertions(+), 24 deletions(-)
 create mode 100644 changelogs/fragments/blockinfile-bytes-fix.yaml

diff --git a/changelogs/fragments/blockinfile-bytes-fix.yaml b/changelogs/fragments/blockinfile-bytes-fix.yaml
new file mode 100644
index 00000000000..48c5755b2f5
--- /dev/null
+++ b/changelogs/fragments/blockinfile-bytes-fix.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - blockinfile - use bytes rather than a native string to prevent a stacktrace in Python 3 when writing to the file (https://github.com/ansible/ansible/issues/46237)
diff --git a/lib/ansible/modules/files/blockinfile.py b/lib/ansible/modules/files/blockinfile.py
index 26beb497d5e..50977ffd1ff 100644
--- a/lib/ansible/modules/files/blockinfile.py
+++ b/lib/ansible/modules/files/blockinfile.py
@@ -309,7 +309,7 @@ def main():
         if original is None or original.endswith(b('\n')):
             result += b('\n')
     else:
-        result = ''
+        result = b''
 
     if module._diff:
         diff['after'] = result
diff --git a/test/integration/targets/blockinfile/tasks/main.yml b/test/integration/targets/blockinfile/tasks/main.yml
index e1a17d358d3..86e066d944e 100644
--- a/test/integration/targets/blockinfile/tasks/main.yml
+++ b/test/integration/targets/blockinfile/tasks/main.yml
@@ -16,13 +16,18 @@
 # You should have received a copy of the GNU General Public License
 # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
 
-- set_fact: output_dir_test={{output_dir}}/test_blockinfile
+- set_fact:
+    output_dir_test: "{{ output_dir }}/test_blockinfile"
 
 - name: make sure our testing sub-directory does not exist
-  file: path="{{ output_dir_test }}" state=absent
+  file:
+    path: "{{ output_dir_test }}"
+    state: absent
 
 - name: create our testing sub-directory
-  file: path="{{ output_dir_test }}" state=directory
+  file:
+    path: "{{ output_dir_test }}"
+    state: directory
 
 ##
 ## blockinfile
@@ -30,38 +35,80 @@
 
 - name: copy the sshd_config to the test dir
   copy:
-      src: sshd_config
-      dest: "{{ output_dir_test }}"
+    src: sshd_config
+    dest: "{{ output_dir_test }}"
 
 - name: insert/update "Match User" configuration block in sshd_config
   blockinfile:
-      path: "{{ output_dir_test }}/sshd_config"
-      block: |
-          Match User ansible-agent
-          PasswordAuthentication no
+    path: "{{ output_dir_test }}/sshd_config"
+    block: |
+      Match User ansible-agent
+      PasswordAuthentication no
   register: blockinfile_test0
+
 - name: check content
   shell: 'grep -e "Match User ansible-agent" -e "PasswordAuthentication no" {{ output_dir_test }}/sshd_config'
   register: blockinfile_test0_grep
-- debug: var=blockinfile_test0
-- debug: var=blockinfile_test0_grep
+
+- debug:
+    var: blockinfile_test0
+    verbosity: 1
+
+- debug:
+    var: blockinfile_test0_grep
+    verbosity: 1
+
 - name: validate first example results
   assert:
-      that:
-          - 'blockinfile_test0.changed is defined'
-          - 'blockinfile_test0.msg is defined'
-          - 'blockinfile_test0.changed'
-          - 'blockinfile_test0.msg == "Block inserted"'
-          - 'blockinfile_test0_grep.stdout_lines | length == 2'
+    that:
+      - 'blockinfile_test0.changed is defined'
+      - 'blockinfile_test0.msg is defined'
+      - 'blockinfile_test0.changed'
+      - 'blockinfile_test0.msg == "Block inserted"'
+      - 'blockinfile_test0_grep.stdout_lines | length == 2'
 
 - name: check idemptotence
   blockinfile:
-      path: "{{ output_dir_test }}/sshd_config"
-      block: |
-          Match User ansible-agent
-          PasswordAuthentication no
+    path: "{{ output_dir_test }}/sshd_config"
+    block: |
+      Match User ansible-agent
+      PasswordAuthentication no
   register: blockinfile_test1
+
 - name: validate idempotence results
   assert:
-      that:
-          - 'not blockinfile_test1.changed'
+    that:
+      - 'not blockinfile_test1.changed'
+
+- name: Create a file with blockinfile
+  blockinfile:
+    path: "{{ output_dir_test }}/empty.txt"
+    block: |
+      Hey
+      there
+    state: present
+    create: yes
+  register: empty_test_1
+
+- name: Run a task that results in an empty file
+  blockinfile:
+    path: "{{ output_dir_test }}/empty.txt"
+    block: |
+      Hey
+      there
+    state: absent
+    create: yes
+  register: empty_test_2
+
+- stat:
+    path: "{{ output_dir_test }}/empty.txt"
+  register: empty_test_stat
+
+- name: Ensure empty file was created
+  assert:
+    that:
+      - empty_test_1 is changed
+      - "'File created' in empty_test_1.msg"
+      - empty_test_2 is changed
+      - "'Block removed' in empty_test_2.msg"
+      - empty_test_stat.stat.size == 0