[temporary-2.9.1-branch-releng-only] lineinfile - properly insert line when line exists and backrefs are enabled (#63763)

Use a separate variable for the boolean test rather than having the same variable sometimes be a boolean and sometimes be a regular expression match object

Add integration tests to cover this scenario
(cherry picked from commit 29d4d318a5)

Co-authored-by: Sam Doran <sdoran@redhat.com>

3 files changed, 34 insertions, 21 deletions

diff --git a/changelogs/fragments/lineinfile-backrefs-match-object-type.yaml b/changelogs/fragments/lineinfile-backrefs-match-object-type.yaml
new file mode 100644
index 0000000000..55d532b356
--- /dev/null
+++ b/changelogs/fragments/lineinfile-backrefs-match-object-type.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - lineinfile - properly handle inserting a line when backrefs are enabled and the line already exists in the file (https://github.com/ansible/ansible/issues/63756)
diff --git a/lib/ansible/modules/files/lineinfile.py b/lib/ansible/modules/files/lineinfile.py
index 26603326b8..dbe2b00084 100644
--- a/lib/ansible/modules/files/lineinfile.py
+++ b/lib/ansible/modules/files/lineinfile.py
@@ -286,7 +286,8 @@ def present(module, dest, regexp, line, insertafter, insertbefore, create,
     # index[0] is the line num where regexp has been found
     # index[1] is the line num where insertafter/insertbefore has been found
     index = [-1, -1]
-    m = None
+    match = None
+    exact_line_match = False
     b_line = to_bytes(line, errors='surrogate_or_strict')
 
     # The module's doc says
@@ -303,18 +304,17 @@ def present(module, dest, regexp, line, insertafter, insertbefore, create,
             match_found = bre_m.search(b_cur_line)
             if match_found:
                 index[0] = lineno
-                m = match_found
+                match = match_found
                 if firstmatch:
                     break
 
     # 2. When no match found on the previous step,
     # parse for searching insertafter/insertbefore:
-    if not m:
+    if not match:
         for lineno, b_cur_line in enumerate(b_lines):
-            match_found = b_line == b_cur_line.rstrip(b'\r\n')
-            if match_found:
+            if b_line == b_cur_line.rstrip(b'\r\n'):
                 index[0] = lineno
-                m = match_found
+                exact_line_match = True
 
             elif bre_ins is not None and bre_ins.search(b_cur_line):
                 if insertafter:
@@ -334,8 +334,8 @@ def present(module, dest, regexp, line, insertafter, insertbefore, create,
     b_linesep = to_bytes(os.linesep, errors='surrogate_or_strict')
     # Exact line or Regexp matched a line in the file
     if index[0] != -1:
-        if backrefs:
-            b_new_line = m.expand(b_line)
+        if backrefs and match:
+            b_new_line = match.expand(b_line)
         else:
             # Don't do backref expansion if not asked.
             b_new_line = b_line
@@ -345,7 +345,7 @@ def present(module, dest, regexp, line, insertafter, insertbefore, create,
 
         # If no regexp was given and no line match is found anywhere in the file,
         # insert the line appropriately if using insertbefore or insertafter
-        if regexp is None and m is None:
+        if regexp is None and match is None and not exact_line_match:
 
             # Insert lines
             if insertafter and insertafter != 'EOF':
diff --git a/test/integration/targets/lineinfile/tasks/main.yml b/test/integration/targets/lineinfile/tasks/main.yml
index 3ede5ded6b..ec6e59e264 100644
--- a/test/integration/targets/lineinfile/tasks/main.yml
+++ b/test/integration/targets/lineinfile/tasks/main.yml
@@ -126,7 +126,7 @@
   lineinfile:
     dest: "{{ output_dir }}/test.txt"
     state: present
-    line: "New line after line 5"
+    line: "New line before line 5"
     insertbefore: "^This is line 5$"
   register: result
 
@@ -144,22 +144,33 @@
 - name: assert test checksum matches after the insert before the last line
   assert:
     that:
-      - "result.stat.checksum == 'e1cae425403507feea4b55bb30a74decfdd4a23e'"
+      - "result.stat.checksum == '2e9e460ff68929e4453eb765761fd99814f6e286'"
 
-- name: replace a line with backrefs
+- name: Replace a line with backrefs
   lineinfile:
     dest: "{{ output_dir }}/test.txt"
     state: present
     line: "This is line 3"
     backrefs: yes
     regexp: "^(REF) .* \\1$"
-  register: result
+  register: backrefs_result1
+
+- name: Replace a line with backrefs again
+  lineinfile:
+    dest: "{{ output_dir }}/test.txt"
+    state: present
+    line: "This is line 3"
+    backrefs: yes
+    regexp: "^(REF) .* \\1$"
+  register: backrefs_result2
+- command: cat {{ output_dir }}/test.txt
 
 - name: assert that the line with backrefs was changed
   assert:
     that:
-      - result is changed
-      - "result.msg == 'line replaced'"
+      - backrefs_result1 is changed
+      - backrefs_result2 is not changed
+      - "backrefs_result1.msg == 'line replaced'"
 
 - name: stat the test after the backref line was replaced
   stat:
@@ -169,7 +180,7 @@
 - name: assert test checksum matches after backref line was replaced
   assert:
     that:
-      - "result.stat.checksum == '2ccdf45d20298f9eaece73b713648e5489a52444'"
+      - "result.stat.checksum == '72f60239a735ae06e769d823f5c2b4232c634d9c'"
 
 - name: remove the middle line
   lineinfile:
@@ -192,7 +203,7 @@
 - name: assert test checksum matches after the middle line was removed
   assert:
     that:
-      - "result.stat.checksum == 'a6ba6865547c19d4c203c38a35e728d6d1942c75'"
+      - "result.stat.checksum == 'd4eeb07bdebab2d1cdb3ec4a3635afa2618ad4ea'"
 
 - name: run a validation script that succeeds
   lineinfile:
@@ -216,7 +227,7 @@
 - name: assert test checksum matches after the validation succeeded
   assert:
     that:
-      - "result.stat.checksum == '76955a4516a00a38aad8427afc9ee3e361024ba5'"
+      - "result.stat.checksum == 'ab56c210ea82839a54487464800fed4878cb2608'"
 
 - name: run a validation script that fails
   lineinfile:
@@ -240,7 +251,7 @@
 - name: assert test checksum matches the previous after the validation failed
   assert:
     that:
-      - "result.stat.checksum == '76955a4516a00a38aad8427afc9ee3e361024ba5'"
+      - "result.stat.checksum == 'ab56c210ea82839a54487464800fed4878cb2608'"
 
 - name: use create=yes
   lineinfile:
@@ -351,7 +362,7 @@
 - name: assert test checksum matches after inserting multiple lines
   assert:
     that:
-      - "result.stat.checksum == 'bf5b711f8f0509355aaeb9d0d61e3e82337c1365'"
+      - "result.stat.checksum == 'fde683229429a4f05d670e6c10afc875e1d5c489'"
 
 - name: replace a line with backrefs included in the line
   lineinfile:
@@ -376,7 +387,7 @@
 - name: assert test checksum matches after backref line was replaced
   assert:
     that:
-      - "result.stat.checksum == '04b7a54d0fb233a4e26c9e625325bb4874841b3c'"
+      - "result.stat.checksum == '981ad35c4b30b03bc3a1beedce0d1e72c491898e'"
 
 ###################################################################
 # issue 8535