Fix re.subn DeprecationWarning in file.replace

Pass count as a keyword argument to all three re.subn() calls in
salt.modules.file.replace to silence the Python 3.12+
DeprecationWarning: 'count' is passed as positional argument.

Add regression test and changelog entry.

Author: dwoz

changelog/69497.fixed.md

@@ -0,0 +1 @@
+Fixed `DeprecationWarning: 'count' is passed as positional argument` emitted by all three `re.subn` calls in `salt.modules.file.replace` on Python 3.12+.

salt/modules/file.py

@@ -2543,7 +2543,7 @@ def replace(
             cpattern,
             repl_str.replace("\\", "\\\\") if backslash_literal else repl_str,
             orig_contents,
-            count,
+            count=count,
         )
 
         found = nrepl > 0
@@ -2700,7 +2700,7 @@ def replace(
                     cpattern,
                     repl.replace(b"\\", b"\\\\") if backslash_literal else repl,
                     r_data,
-                    count,
+                    count=count,
                 )
 
                 # found anything? (even if no change)
@@ -2759,7 +2759,7 @@ def replace(
                             cpattern,
                             repl.replace(b"\\", b"\\\\") if backslash_literal else repl,
                             r_data,
-                            count,
+                            count=count,
                         )
                         try:
                             w_file.write(salt.utils.stringutils.to_str(result))

tests/pytests/functional/modules/file/test_replace.py

@@ -211,3 +211,17 @@ def test_replace_no_modify_time_update_on_no_change(file, multiline_file):
 def test_backslash_literal(file, multiline_file):
     file.replace(str(multiline_file), r"Etiam", "Emma", backslash_literal=True)
     assert "Emma" in multiline_file.read_text()
+
+
+def test_replace_count_no_deprecation_warning(file, multiline_file):
+    """
+    Regression test for https://github.com/saltstack/salt/pull/69497.
+    file.replace must not emit a DeprecationWarning for passing 'count'
+    as a positional argument to re.subn.
+    """
+    import warnings
+
+    with warnings.catch_warnings():
+        warnings.simplefilter("error", DeprecationWarning)
+        file.replace(str(multiline_file), r"Etiam", "Salticus", count=1)
+    assert "Salticus" in multiline_file.read_text()