Fix formatting instability on long if conditions with if-then-else=fit-or-vertical

CHANGES.md

@@ -4,6 +4,13 @@ Items marked with an asterisk (\*) are changes that are likely to format
 existing code differently from the previous release when using the default
 profile. This started with version 0.26.0.
 
+## unreleased
+
+### Fixed
+
+- Fix instability on long if-then-else with `if-then-else=fit-or-vertical`
+  (#2797, @MisterDA)
+
 ## 0.29.0
 
 ### Highlight

lib/Params.ml

@@ -959,7 +959,15 @@ let get_if_then_else (c : Conf.t) ~cmts_before_opt ~pro ~first ~last
             | _ -> 0 )
       ; cond= cond ()
       ; box_keyword_and_expr= Fn.id
-      ; branch_pro= branch_pro ~begin_end_offset:0 ()
+      ; branch_pro=
+          ( if
+              (not has_beginend) && (not has_cmts_after_kw)
+              && not (Location.is_single_line expr_loc c.fmt_opts.margin.v)
+            then
+              match cmts_before_opt xbch.ast.pexp_loc with
+              | Some cmts -> break 1000 2 $ cmts
+              | None -> branch_pro ~begin_end_offset:0 ()
+            else branch_pro ~begin_end_offset:0 () )
       ; wrap_parens=
           wrap_parens
             ~wrap_breaks:

test/passing/refs.ahrefs/ite-compact.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-compact_closing.ml.ref

@@ -199,3 +199,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-fit_or_vertical.ml.ref

@@ -218,3 +218,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite-fit_or_vertical_closing.ml.ref

@@ -227,3 +227,12 @@ let () =
     ()
   end else
         ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite-fit_or_vertical_no_indicate.ml.ref

@@ -218,3 +218,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite-kr.ml.ref

@@ -256,3 +256,12 @@ let () =
     ()
   end else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite-kr_closing.ml.ref

@@ -263,3 +263,12 @@ let () =
     ()
   end else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite-kw_first.ml.ref

@@ -212,3 +212,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-kw_first_closing.ml.ref

@@ -229,3 +229,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-kw_first_no_indicate.ml.ref

@@ -212,3 +212,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-no_indicate.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.ahrefs/ite-vertical.ml.ref

@@ -255,3 +255,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.ahrefs/ite.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-compact.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-compact_closing.ml.ref

@@ -197,3 +197,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-fit_or_vertical.ml.ref

@@ -218,3 +218,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite-fit_or_vertical_closing.ml.ref

@@ -227,3 +227,12 @@ let () =
     ()
   end else
         ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite-fit_or_vertical_no_indicate.ml.ref

@@ -218,3 +218,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite-kr.ml.ref

@@ -258,3 +258,12 @@ let () =
     ()
   end else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite-kr_closing.ml.ref

@@ -265,3 +265,12 @@ let () =
     ()
   end else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite-kw_first.ml.ref

@@ -212,3 +212,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-kw_first_closing.ml.ref

@@ -227,3 +227,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-kw_first_no_indicate.ml.ref

@@ -212,3 +212,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-no_indicate.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.default/ite-vertical.ml.ref

@@ -257,3 +257,12 @@ let () =
   end
   else
     ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else
+    2

test/passing/refs.default/ite.ml.ref

@@ -182,3 +182,11 @@ let () =
     ()
   end
   else ()
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t
+  then
+    (* comment *)
+    1
+  else 2

test/passing/refs.janestreet/ite-compact.ml.ref

@@ -184,3 +184,11 @@ let () =
     ()
   else ()
 ;;
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t then
+    (* comment *)
+    1
+  else 2
+;;

test/passing/refs.janestreet/ite-compact_closing.ml.ref

@@ -196,3 +196,11 @@ let () =
     ()
   else ()
 ;;
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t then
+    (* comment *)
+    1
+  else 2
+;;

test/passing/refs.janestreet/ite-fit_or_vertical.ml.ref

@@ -233,3 +233,12 @@ let () =
   else
     ()
 ;;
+
+(* Long condition with comment after then keyword *)
+let test =
+  if long_function_name_to_force_break a b c d e f g h i j k l m n o p q r s t then
+    (* comment *)
+    1
+  else
+    2
+;;