Ensure that single space between tasks is preserved when using --write (#3641)

Co-authored-by: Sorin Sbarnea <ssbarnea@redhat.com>

Author: shatakshiiii

.github/workflows/tox.yml

@@ -71,7 +71,7 @@ jobs:
       WSLENV: FORCE_COLOR:PYTEST_REQPASS:TOXENV:GITHUB_STEP_SUMMARY
       # Number of expected test passes, safety measure for accidental skip of
       # tests. Update value if you add/remove tests.
-      PYTEST_REQPASS: 809
+      PYTEST_REQPASS: 811
     steps:
       - name: Activate WSL1
         if: "contains(matrix.shell, 'wsl')"

src/ansiblelint/yaml_utils.py

@@ -695,12 +695,19 @@ def write_comment(
                     ruamel.yaml.events.CollectionEndEvent,
                     ruamel.yaml.events.DocumentEndEvent,
                     ruamel.yaml.events.StreamEndEvent,
+                    ruamel.yaml.events.MappingStartEvent,
                 ),
             )
         ):
             # drop pure whitespace pre comments
             # does not apply to End events since they consume one of the newlines.
             value = ""
+        elif (
+            pre
+            and not value.strip()
+            and isinstance(self.event, ruamel.yaml.events.MappingStartEvent)
+        ):
+            value = self._re_repeat_blank_lines.sub("", value)
         elif pre:
             # preserve content in pre comment with at least one newline,
             # but no extra blank lines.

test/fixtures/formatting-after/fmt-4.yml

@@ -0,0 +1,22 @@
+---
+- name: Gather all legacy facts
+  cisco.ios.ios_facts:
+
+- name: Update modification and access time of given file
+  ansible.builtin.file:
+    path: /etc/some_file
+    state: file
+    modification_time: now
+    access_time: now
+
+- name: Disable ufw service
+  ansible.builtin.service:
+    name: ufw
+    enabled: false
+    state: stopped
+  when: '"ufw" in services'
+
+- name: Remove file (delete file)
+  ansible.builtin.file:
+    path: /etc/foo.txt
+    state: absent

test/fixtures/formatting-after/fmt-5.yml

@@ -0,0 +1,25 @@
+---
+- name: Test this playbook
+  hosts: all
+  tasks:
+    - name: Gather all legacy facts
+      cisco.ios.ios_facts:
+
+    - name: Update modification and access time of given file
+      ansible.builtin.file:
+        path: /etc/some_file
+        state: file
+        modification_time: now
+        access_time: now
+
+    - name: Disable ufw service
+      ansible.builtin.service:
+        name: ufw
+        enabled: false
+        state: stopped
+      when: '"ufw" in services'
+
+    - name: Remove file (delete file)
+      ansible.builtin.file:
+        path: /etc/foo.txt
+        state: absent

test/fixtures/formatting-before/fmt-4.yml

@@ -0,0 +1,25 @@
+---
+- name: Gather all legacy facts
+  cisco.ios.ios_facts:
+
+- name: Update modification and access time of given file
+  ansible.builtin.file:
+    path: /etc/some_file
+    state: file
+    modification_time: now
+    access_time: now
+
+
+- name: Disable ufw service
+  ansible.builtin.service:
+    name: ufw
+    enabled: false
+    state: stopped
+  when: '"ufw" in services'
+
+
+
+- name: Remove file (delete file)
+  ansible.builtin.file:
+    path: /etc/foo.txt
+    state: absent

test/fixtures/formatting-before/fmt-5.yml

@@ -0,0 +1,28 @@
+---
+- name: Test this playbook
+  hosts: all
+  tasks:
+    - name: Gather all legacy facts
+      cisco.ios.ios_facts:
+
+    - name: Update modification and access time of given file
+      ansible.builtin.file:
+        path: /etc/some_file
+        state: file
+        modification_time: now
+        access_time: now
+
+
+    - name: Disable ufw service
+      ansible.builtin.service:
+        name: ufw
+        enabled: false
+        state: stopped
+      when: '"ufw" in services'
+
+
+
+    - name: Remove file (delete file)
+      ansible.builtin.file:
+        path: /etc/foo.txt
+        state: absent

test/fixtures/formatting-prettier/fmt-4.yml

@@ -0,0 +1,22 @@
+---
+- name: Gather all legacy facts
+  cisco.ios.ios_facts:
+
+- name: Update modification and access time of given file
+  ansible.builtin.file:
+    path: /etc/some_file
+    state: file
+    modification_time: now
+    access_time: now
+
+- name: Disable ufw service
+  ansible.builtin.service:
+    name: ufw
+    enabled: false
+    state: stopped
+  when: '"ufw" in services'
+
+- name: Remove file (delete file)
+  ansible.builtin.file:
+    path: /etc/foo.txt
+    state: absent

test/fixtures/formatting-prettier/fmt-5.yml

@@ -0,0 +1,25 @@
+---
+- name: Test this playbook
+  hosts: all
+  tasks:
+    - name: Gather all legacy facts
+      cisco.ios.ios_facts:
+
+    - name: Update modification and access time of given file
+      ansible.builtin.file:
+        path: /etc/some_file
+        state: file
+        modification_time: now
+        access_time: now
+
+    - name: Disable ufw service
+      ansible.builtin.service:
+        name: ufw
+        enabled: false
+        state: stopped
+      when: '"ufw" in services'
+
+    - name: Remove file (delete file)
+      ansible.builtin.file:
+        path: /etc/foo.txt
+        state: absent

test/test_yaml_utils.py

@@ -222,9 +222,11 @@ def fixture_yaml_formatting_fixtures(fixture_filename: str) -> tuple[str, str, s
 @pytest.mark.parametrize(
     "fixture_filename",
     (
-        "fmt-1.yml",
-        "fmt-2.yml",
-        "fmt-3.yml",
+        pytest.param("fmt-1.yml", id="1"),
+        pytest.param("fmt-2.yml", id="2"),
+        pytest.param("fmt-3.yml", id="3"),
+        pytest.param("fmt-4.yml", id="4"),
+        pytest.param("fmt-5.yml", id="5"),
     ),
 )
 def test_formatted_yaml_loader_dumper(