fix: indent match arm body when conditions break onto multiple lines

src/printer.mjs

@@ -49,6 +49,7 @@ const {
   indent,
   dedent,
   ifBreak,
+  indentIfBreak,
   hardline,
   hardlineWithoutBreakParent,
   softline,
@@ -2885,17 +2886,24 @@ function printNode(path, options, print) {
             ? hardline
             : "";
 
+        const condsGroupId = Symbol("match-arm-conds");
+
         return [
           "",
           hardline,
           maybeEmptyLineBetweenArms,
           ...maybeLeadingComment,
           group([
-            group([conds, indent(line)]),
-            "=> ",
-            body,
-            maybeTrailingComma,
-            ...maybeTrailingComment,
+            group([conds, indent(line)], { id: condsGroupId }),
+            // When the conditions break onto multiple lines, the `=>` moves to
+            // its own indented line - the body then needs the same extra
+            // indent level for its own line breaks (see #2435).
+            indentIfBreak(
+              ["=> ", body, maybeTrailingComma, ...maybeTrailingComment],
+              {
+                groupId: condsGroupId,
+              }
+            ),
           ]),
         ].slice(!path.isFirst ? 0 : 1);
       }, "arms");

tests/match/__snapshots__/jsfmt.spec.mjs.snap

@@ -1,4 +1,4 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
+// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
 exports[`match.php 1`] = `
 ====================================options=====================================
@@ -70,6 +70,49 @@ match($really_really_really_really_really_really_really_really_long_variable_nam
 default => null
 };
 
+// https://github.com/prettier/plugin-php/issues/2435
+// When the conditions of a match arm break onto multiple lines, the body
+// on the indented \`=>\` line must keep the extra indent for its own breaks.
+echo match ($operation) {
+    "short", "really very long option 2" => SomeClass::fairlyLongMethodNameThatRunsOn($variable, ["short", "short"]),
+};
+
+// Same, with a method chain as the body and a trailing comment on the arm.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep(outerFunction(innerFunction(deepestFunction($value))))
+            ->thirdStep(fn($item) => $item + 1), // trailing comment
+    default => null,
+};
+
+// Same, with a method chain whose last step takes a nested chain argument.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep($second)
+            ->thirdStep(makeThing($inner->levelFour($deep))->levelTwo($second)),
+    default => null,
+};
+
+// Same, with an array as the body.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => [
+            "first entry of the array body",
+            "second entry of the array body",
+        ],
+    default => null,
+};
+
 =====================================output=====================================
 <?php
 
@@ -158,6 +201,51 @@ match (
     default => null
 };
 
+// https://github.com/prettier/plugin-php/issues/2435
+// When the conditions of a match arm break onto multiple lines, the body
+// on the indented \`=>\` line must keep the extra indent for its own breaks.
+echo match ($operation) {
+    "short",
+    "really very long option 2"
+        => SomeClass::fairlyLongMethodNameThatRunsOn($variable, [
+            "short",
+            "short"
+        ])
+};
+
+// Same, with a method chain as the body and a trailing comment on the arm.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep(outerFunction(innerFunction(deepestFunction($value))))
+            ->thirdStep(fn($item) => $item + 1), // trailing comment
+    default => null
+};
+
+// Same, with a method chain whose last step takes a nested chain argument.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep($second)
+            ->thirdStep(makeThing($inner->levelFour($deep))->levelTwo($second)),
+    default => null
+};
+
+// Same, with an array as the body.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => ["first entry of the array body", "second entry of the array body"],
+    default => null
+};
+
 ================================================================================
 `;
 
@@ -231,6 +319,49 @@ match($really_really_really_really_really_really_really_really_long_variable_nam
 default => null
 };
 
+// https://github.com/prettier/plugin-php/issues/2435
+// When the conditions of a match arm break onto multiple lines, the body
+// on the indented \`=>\` line must keep the extra indent for its own breaks.
+echo match ($operation) {
+    "short", "really very long option 2" => SomeClass::fairlyLongMethodNameThatRunsOn($variable, ["short", "short"]),
+};
+
+// Same, with a method chain as the body and a trailing comment on the arm.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep(outerFunction(innerFunction(deepestFunction($value))))
+            ->thirdStep(fn($item) => $item + 1), // trailing comment
+    default => null,
+};
+
+// Same, with a method chain whose last step takes a nested chain argument.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep($second)
+            ->thirdStep(makeThing($inner->levelFour($deep))->levelTwo($second)),
+    default => null,
+};
+
+// Same, with an array as the body.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => [
+            "first entry of the array body",
+            "second entry of the array body",
+        ],
+    default => null,
+};
+
 =====================================output=====================================
 <?php
 
@@ -319,5 +450,50 @@ match (
     default => null,
 };
 
+// https://github.com/prettier/plugin-php/issues/2435
+// When the conditions of a match arm break onto multiple lines, the body
+// on the indented \`=>\` line must keep the extra indent for its own breaks.
+echo match ($operation) {
+    "short",
+    "really very long option 2"
+        => SomeClass::fairlyLongMethodNameThatRunsOn($variable, [
+            "short",
+            "short",
+        ]),
+};
+
+// Same, with a method chain as the body and a trailing comment on the arm.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep(outerFunction(innerFunction(deepestFunction($value))))
+            ->thirdStep(fn($item) => $item + 1), // trailing comment
+    default => null,
+};
+
+// Same, with a method chain whose last step takes a nested chain argument.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep($second)
+            ->thirdStep(makeThing($inner->levelFour($deep))->levelTwo($second)),
+    default => null,
+};
+
+// Same, with an array as the body.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => ["first entry of the array body", "second entry of the array body"],
+    default => null,
+};
+
 ================================================================================
 `;

tests/match/match.php

@@ -59,3 +59,46 @@
 match($really_really_really_really_really_really_really_really_long_variable_name) {
 default => null
 };
+
+// https://github.com/prettier/plugin-php/issues/2435
+// When the conditions of a match arm break onto multiple lines, the body
+// on the indented `=>` line must keep the extra indent for its own breaks.
+echo match ($operation) {
+    "short", "really very long option 2" => SomeClass::fairlyLongMethodNameThatRunsOn($variable, ["short", "short"]),
+};
+
+// Same, with a method chain as the body and a trailing comment on the arm.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep(outerFunction(innerFunction(deepestFunction($value))))
+            ->thirdStep(fn($item) => $item + 1), // trailing comment
+    default => null,
+};
+
+// Same, with a method chain whose last step takes a nested chain argument.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => $service
+            ->firstStep($input)
+            ->secondStep($second)
+            ->thirdStep(makeThing($inner->levelFour($deep))->levelTwo($second)),
+    default => null,
+};
+
+// Same, with an array as the body.
+echo match ($operation) {
+    "a very long first option text",
+    "a very long second option text",
+    "a third option"
+        => [
+            "first entry of the array body",
+            "second entry of the array body",
+        ],
+    default => null,
+};