Fix formatting for if clauses in match-case blocks

CHANGES.md

@@ -11,6 +11,8 @@
 <!-- Changes that affect Black's stable style -->
 
 - Don't move comments along with delimiters, which could cause crashes (#4248)
+- Fixed a bug where `if` clauses in `match-case` blocks are not wrapped with parenthesis
+  when the line is too long (#4269)
 
 ### Preview style
 

src/black/linegen.py

@@ -1310,6 +1310,13 @@ def normalize_invisible_parens(  # noqa: C901
                 child, parens_after={"case"}, mode=mode, features=features
             )
 
+        # Fixes a bug where invisible parens are not properly wrapped around
+        # if statement.
+        if isinstance(child, Node) and child.type == syms.guard:
+            normalize_invisible_parens(
+                child, parens_after={"if"}, mode=mode, features=features
+            )
+
         # Add parentheses around long tuple unpacking in assignments.
         if (
             index == 0

tests/data/cases/pattern_matching_complex.py

@@ -83,7 +83,7 @@
 match x:
     case [0]:
         y = 0
-    case [1, 0] if (x := x[:0]):
+    case [1, 0] if x := x[:0]:
         y = 1
     case [1, 0]:
         y = 2

tests/data/cases/pattern_matching_with_if_stmt.py

@@ -0,0 +1,56 @@
+# flags: --minimum-version=3.10
+match "test":
+    case "test" if "first long condition" != "some loooooooooooooooooooooooooooooooooooooog condition":
+        print("Test")
+
+match match:
+    case "test" if case != "not very loooooooooooooog condition":
+        print("No format change")
+
+match "test":
+    case "test" if "any long condition" != "another long condition" and "this is a long condition":
+        print("Test")
+
+match "test":
+    case "test" if "any long condition" != "another long condition" and "this is a looooong condition":
+        print("Test")
+
+# case black_test_patma_052 (originally in the pattern_matching_complex test case)
+match x:
+    case [1, 0] if x := x[:0]:
+        y = 1
+    case [1, 0] if (x := x[:0]):
+        y = 1
+
+# output
+
+match "test":
+    case "test" if (
+        "first long condition"
+        != "some loooooooooooooooooooooooooooooooooooooog condition"
+    ):
+        print("Test")
+
+match match:
+    case "test" if case != "not very loooooooooooooog condition":
+        print("No format change")
+
+match "test":
+    case "test" if (
+        "any long condition" != "another long condition" and "this is a long condition"
+    ):
+        print("Test")
+
+match "test":
+    case "test" if (
+        "any long condition" != "another long condition"
+        and "this is a looooong condition"
+    ):
+        print("Test")
+
+# case black_test_patma_052 (originally in the pattern_matching_complex test case)
+match x:
+    case [1, 0] if x := x[:0]:
+        y = 1
+    case [1, 0] if x := x[:0]:
+        y = 1