fix: align breaking of instanceof with binary expression in assignments

src/printers/classes.ts

@@ -4,8 +4,8 @@ import { SyntaxType, type NamedNode } from "../node-types.ts";
 import {
   definedKeys,
   hasChild,
-  hasLeadingComments,
   indentInParentheses,
+  printAssignment,
   printBlock,
   printBlockStatements,
   printBodyDeclarations,
@@ -16,7 +16,7 @@ import {
   type NamedNodePrinters
 } from "./helpers.ts";
 
-const { group, hardline, indent, indentIfBreak, join, line } = builders;
+const { group, hardline, indent, join, line } = builders;
 
 export default {
   class_declaration(path, print) {
@@ -96,31 +96,16 @@ export default {
   field_declaration: printVariableDeclaration,
 
   variable_declarator(path, print) {
-    const declarator = [path.call(print, "nameNode")];
+    const leftDoc = [path.call(print, "nameNode")];
     if (hasChild(path, "dimensionsNode")) {
-      declarator.push(path.call(print, "dimensionsNode"));
+      leftDoc.push(path.call(print, "dimensionsNode"));
     }
-    if (!hasChild(path, "valueNode")) {
-      return declarator;
-    }
-    declarator.push(" =");
-    const value = path.call(print, "valueNode");
-    if (
-      path.node.valueNode.type === SyntaxType.BinaryExpression ||
-      (path.node.valueNode.type === SyntaxType.TernaryExpression &&
-        path.node.valueNode.conditionNode.type ===
-          SyntaxType.BinaryExpression) ||
-      hasLeadingComments(path.node.valueNode)
-    ) {
-      declarator.push(group(indent([line, value])));
-    } else {
-      const groupId = Symbol("assignment");
-      declarator.push(
-        group(indent(line), { id: groupId }),
-        indentIfBreak(value, { groupId })
-      );
-    }
-    return group(declarator);
+    return printAssignment(
+      leftDoc,
+      " =",
+      hasChild(path, "valueNode") ? path.call(print, "valueNode") : undefined,
+      path.node.valueNode
+    );
   },
 
   method_declaration(path, print) {

src/printers/expressions.ts

@@ -8,10 +8,10 @@ import {
 } from "../node-types.ts";
 import {
   hasChild,
-  hasLeadingComments,
   hasType,
   indentInParentheses,
   isReturnOrThrowStatement,
+  printAssignment,
   printDanglingComments,
   shouldFlatten,
   type JavaParserOptions,
@@ -232,26 +232,13 @@ export default {
   },
 
   assignment_expression(path, print) {
-    const { operatorNode, rightNode } = path.node;
-    const parts = [path.call(print, "leftNode"), " ", operatorNode.type];
-    const right = path.call(print, "rightNode");
-
-    if (
-      rightNode.type === SyntaxType.BinaryExpression ||
-      (rightNode.type === SyntaxType.TernaryExpression &&
-        rightNode.conditionNode.type === SyntaxType.BinaryExpression) ||
-      hasLeadingComments(rightNode)
-    ) {
-      parts.push(group(indent([line, right])));
-    } else {
-      const groupId = Symbol("assignment");
-      parts.push(
-        group(indent(line), { id: groupId }),
-        indentIfBreak(right, { groupId })
-      );
-    }
-
-    return parts;
+    const { node } = path;
+    return printAssignment(
+      path.call(print, "leftNode"),
+      [" ", node.operatorNode.type],
+      path.call(print, "rightNode"),
+      node.rightNode
+    );
   },
 
   binary_expression(path, print, options) {

src/printers/helpers.ts

@@ -2,14 +2,26 @@ import type { AstPath, Doc, Options, ParserOptions } from "prettier";
 import { builders, utils } from "prettier/doc";
 import {
   SyntaxType,
+  type ArrayInitializerNode,
   type CommentNode,
+  type ExpressionNode,
   type NamedNode,
   type NamedType,
   type SyntaxNode,
   type TypeString
 } from "../node-types.ts";
 
-const { group, hardline, ifBreak, indent, join, line, softline } = builders;
+const {
+  group,
+  hardline,
+  ifBreak,
+  indent,
+  indentIfBreak,
+  join,
+  line,
+  lineSuffixBoundary,
+  softline
+} = builders;
 const { mapDoc } = utils;
 
 export function hasType<T extends NamedType>(
@@ -347,6 +359,40 @@ export function printVariableDeclaration(
   return declaration;
 }
 
+export function printAssignment(
+  leftDoc: Doc,
+  operator: Doc,
+  rightDoc?: Doc,
+  rightNode?: ArrayInitializerNode | ExpressionNode
+) {
+  if (!rightDoc || !rightNode) {
+    return leftDoc;
+  }
+
+  const breakAfterOperator =
+    rightNode.type === SyntaxType.BinaryExpression ||
+    rightNode.type === SyntaxType.InstanceofExpression ||
+    (rightNode.type === SyntaxType.TernaryExpression &&
+      (rightNode.conditionNode.type === SyntaxType.BinaryExpression ||
+        rightNode.conditionNode.type === SyntaxType.InstanceofExpression)) ||
+    hasLeadingComments(rightNode);
+
+  if (breakAfterOperator) {
+    // First break after operator, then right-hand side
+    return group([leftDoc, operator, group(indent([line, rightDoc]))]);
+  }
+
+  // First break right-hand side, then after operator
+  const groupId = Symbol("assignment");
+  return group([
+    leftDoc,
+    operator,
+    group(indent(line), { id: groupId }),
+    lineSuffixBoundary,
+    indentIfBreak(rightDoc, { groupId })
+  ]);
+}
+
 export function printTextBlock(
   path: NamedNodePath<SyntaxType.StringLiteral>,
   contents: Doc

test/unit-test/binary_expressions/operator-position-end/_input.java

@@ -132,6 +132,12 @@ void instanceOf() {
 
     e instanceof @Ann final E baz;
     f instanceof final @Ann E qux;
+
+    aaaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    aaaaaaaaaa = bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
+
+    var aaaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    var aaaaaaaaaa = bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
   }
 
   void unaryExpression() {

test/unit-test/binary_expressions/operator-position-end/_output.java

@@ -247,6 +247,16 @@ void instanceOf() {
 
     e instanceof @Ann final E baz;
     f instanceof final @Ann E qux;
+
+    aaaaaaaaaaaaaaaaaaaa =
+      bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    aaaaaaaaaa =
+      bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
+
+    var aaaaaaaaaaaaaaaaaaaa =
+      bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    var aaaaaaaaaa =
+      bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
   }
 
   void unaryExpression() {

test/unit-test/binary_expressions/operator-position-start/_input.java

@@ -132,6 +132,12 @@ void instanceOf() {
 
     e instanceof @Ann final E baz;
     f instanceof final @Ann E qux;
+
+    aaaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    aaaaaaaaaa = bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
+
+    var aaaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    var aaaaaaaaaa = bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
   }
 
   void unaryExpression() {

test/unit-test/binary_expressions/operator-position-start/_output.java

@@ -242,6 +242,16 @@ void instanceOf() {
 
     e instanceof @Ann final E baz;
     f instanceof final @Ann E qux;
+
+    aaaaaaaaaaaaaaaaaaaa =
+      bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    aaaaaaaaaa =
+      bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
+
+    var aaaaaaaaaaaaaaaaaaaa =
+      bbbbbbbbbbbbbbbbbbbb instanceof Cccccccccccccccccccc cccccccccccccccccccc;
+    var aaaaaaaaaa =
+      bbbbbbbbbb instanceof Cccccccccc cccccccccc ? dddddddddd : eeeeeeeeee;
   }
 
   void unaryExpression() {