fix: break empty switch/rule, try/catch/finally, and if blocks

Author: jtkiesel

packages/prettier-plugin-java/src/comments.ts

@@ -99,7 +99,8 @@ export function handleLineComment(
     handleIfStatementComments,
     handleJumpStatementComments,
     handleLabeledStatementComments,
-    handleNameComments
+    handleNameComments,
+    handleTryStatementComments
   ].some(fn => fn(commentNode, options));
 }
 
@@ -247,6 +248,37 @@ function handleNameComments(commentNode: JavaComment) {
   return false;
 }
 
+function handleTryStatementComments(commentNode: JavaComment) {
+  const { enclosingNode, followingNode } = commentNode;
+  if (
+    enclosingNode &&
+    ["catches", "tryStatement"].includes(enclosingNode.name) &&
+    followingNode &&
+    isNonTerminal(followingNode)
+  ) {
+    const block = (
+      followingNode.name === "catches"
+        ? followingNode.children.catchClause[0]
+        : followingNode.name === "catchClause" ||
+            followingNode.name === "finally"
+          ? followingNode
+          : null
+    )?.children.block[0];
+    if (!block) {
+      return false;
+    }
+    const blockStatement =
+      block.children.blockStatements?.[0].children.blockStatement[0];
+    if (blockStatement) {
+      util.addLeadingComment(blockStatement, commentNode);
+    } else {
+      util.addDanglingComment(block, commentNode, undefined);
+    }
+    return true;
+  }
+  return false;
+}
+
 function isBinaryOperator(node?: JavaNode) {
   return (
     node !== undefined &&

packages/prettier-plugin-java/src/printers/helpers.ts

@@ -263,18 +263,52 @@ export function printArrayInitializer<
 }
 
 export function printBlock(path: AstPath<JavaNonTerminal>, contents: Doc[]) {
-  if (!contents.length) {
-    const danglingComments = printDanglingComments(path);
-    return danglingComments.length
-      ? ["{", indent([hardline, ...danglingComments]), hardline, "}"]
-      : "{}";
+  if (contents.length) {
+    return group([
+      "{",
+      indent([hardline, ...join(hardline, contents)]),
+      hardline,
+      "}"
+    ]);
   }
-  return group([
-    "{",
-    indent([hardline, ...join(hardline, contents)]),
-    hardline,
-    "}"
-  ]);
+  const danglingComments = printDanglingComments(path);
+  if (danglingComments.length) {
+    return ["{", indent([hardline, ...danglingComments]), hardline, "}"];
+  }
+  const parent = path.grandparent;
+  const grandparent = path.getNode(4);
+  const greatGrandparent = path.getNode(6);
+  return (grandparent?.name === "catches" &&
+    grandparent.children.catchClause.length === 1 &&
+    (greatGrandparent?.name === "tryStatement" ||
+      greatGrandparent?.name === "tryWithResourcesStatement") &&
+    !greatGrandparent.children.finally) ||
+    (greatGrandparent &&
+      [
+        "basicForStatement",
+        "doStatement",
+        "enhancedForStatement",
+        "whileStatement"
+      ].includes(greatGrandparent.name)) ||
+    [
+      "annotationInterfaceBody",
+      "classBody",
+      "constructorBody",
+      "enumBody",
+      "interfaceBody",
+      "moduleDeclaration",
+      "recordBody"
+    ].includes(path.node.name) ||
+    (parent &&
+      [
+        "instanceInitializer",
+        "lambdaBody",
+        "methodBody",
+        "staticInitializer",
+        "synchronizedStatement"
+      ].includes(parent.name))
+    ? "{}"
+    : ["{", hardline, "}"];
 }
 
 export function printName(

packages/prettier-plugin-java/test/unit-test/binary_expressions/operator-position-end/_output.java

@@ -170,7 +170,8 @@ void parentheses() {
     var sizeIndex = ((index - 1) >>> level) & MASK;
     var from = offset > left ? 0 : (left - offset) >> level;
     var to = (right - offset) >> (level + 1);
-    if (rawIndex < 1 << (list._level + SHIFT)) {}
+    if (rawIndex < 1 << (list._level + SHIFT)) {
+    }
     var res = size < SIZE ? 0 : ((size - 1) >>> SHIFT) << SHIFT;
     sign = (1 - 2 * b[3]) >> 7;
     exponent = ((b[3] << 1) & 0xff) | (b[2] >> (7 - 127));
@@ -213,12 +214,14 @@ void parentheses() {
       (aaaaaaaaaa + bbbbbbbbbb == cccccccccc + dddddddddd &&
         eeeeeeeeee + ffffffffff == gggggggggg + hhhhhhhhhh) ||
       iiiiiiiiii
-    ) {}
+    ) {
+    }
 
     if (
       (((((a * b + c) << d < e == f) & g) ^ h) | i && j) ||
       (k && l | (m ^ (n & (o != p > q >> (r - s / t)))))
-    ) {}
+    ) {
+    }
 
     if (
       (aaaaaaaaaa + bbbbbbbbbb == cccccccccc + dddddddddd &&
@@ -227,7 +230,8 @@ void parentheses() {
         mmmmmmmmmm + nnnnnnnnnn == oooooooooo + pppppppppp) ||
       (qqqqqqqqqq + rrrrrrrrrr == ssssssssss + tttttttttt &&
         uuuuuuuuuu + vvvvvvvvvv == wwwwwwwwww + xxxxxxxxxxx)
-    ) {}
+    ) {
+    }
   }
 
   void instanceOf() {

packages/prettier-plugin-java/test/unit-test/binary_expressions/operator-position-start/_output.java

@@ -163,7 +163,8 @@ void parentheses() {
     var sizeIndex = ((index - 1) >>> level) & MASK;
     var from = offset > left ? 0 : (left - offset) >> level;
     var to = (right - offset) >> (level + 1);
-    if (rawIndex < 1 << (list._level + SHIFT)) {}
+    if (rawIndex < 1 << (list._level + SHIFT)) {
+    }
     var res = size < SIZE ? 0 : ((size - 1) >>> SHIFT) << SHIFT;
     sign = (1 - 2 * b[3]) >> 7;
     exponent = ((b[3] << 1) & 0xff) | (b[2] >> (7 - 127));
@@ -206,12 +207,14 @@ void parentheses() {
       (aaaaaaaaaa + bbbbbbbbbb == cccccccccc + dddddddddd
         && eeeeeeeeee + ffffffffff == gggggggggg + hhhhhhhhhh)
       || iiiiiiiiii
-    ) {}
+    ) {
+    }
 
     if (
       (((((a * b + c) << d < e == f) & g) ^ h) | i && j)
       || (k && l | (m ^ (n & (o != p > q >> (r - s / t)))))
-    ) {}
+    ) {
+    }
 
     if (
       (aaaaaaaaaa + bbbbbbbbbb == cccccccccc + dddddddddd
@@ -220,7 +223,8 @@ void parentheses() {
         && mmmmmmmmmm + nnnnnnnnnn == oooooooooo + pppppppppp)
       || (qqqqqqqqqq + rrrrrrrrrr == ssssssssss + tttttttttt
         && uuuuuuuuuu + vvvvvvvvvv == wwwwwwwwww + xxxxxxxxxxx)
-    ) {}
+    ) {
+    }
   }
 
   void instanceOf() {

packages/prettier-plugin-java/test/unit-test/comments/comments-blocks-and-statements/if-statement/_output.java

@@ -4,18 +4,22 @@ void commentsIfLineComment() {
     if (
       // test
       t
-    ) {}
+    ) {
+    }
 
     if (
       t // test
-    ) {}
+    ) {
+    }
 
-    if (t) {} // test
+    if (t) {
+    } // test
 
     if (
       // test
       t
-    ) {}
+    ) {
+    }
 
     if (
       true // comment
@@ -25,26 +29,38 @@ void commentsIfLineComment() {
   }
 
   void commentsIfBlockComment() {
-    if (/* test */ t) {}
+    if (/* test */ t) {
+    }
 
-    if (t /* test */) {}
+    if (t /* test */) {
+    }
 
-    if (t) /* test */ {}
+    if (t) /* test */ {
+    }
 
-    if (/* test */ t) {}
+    if (/* test */ t) {
+    }
   }
 
   void commentsElseLineComment() {
-    if (t) {}
+    if (t) {
+    }
     // test
-    else {}
+    else {
+    }
 
-    if (t) {} else {} // test
+    if (t) {
+    } else {
+    } // test
   }
 
   void commentsElseBlockComment() {
-    if (t) {} /* test */ else {}
+    if (t) {
+    } /* test */ else {
+    }
 
-    if (t) {} else /* test */ {}
+    if (t) {
+    } else /* test */ {
+    }
   }
 }

packages/prettier-plugin-java/test/unit-test/expressions/_output.java

@@ -73,7 +73,8 @@ public void instanceOf() {
   }
 
   public void printSimple() {
-    if (myValue == 42) {}
+    if (myValue == 42) {
+    }
 
     if (myValue != 42) {
       System.out.println("Why not 42 !");
@@ -92,33 +93,40 @@ public void printIf() {
       myValue == 42 ||
       (myValue == 42 && myValue == 42 && myValue == 42) ||
       (myValue == 42 && myValue == 42)
-    ) {}
+    ) {
+    }
 
     if (
       (myValue != 42 && 42 / 42) ||
       (myValue & 42 && myValue > 42) ||
       (myValue < 42 && myValue == 42)
-    ) {}
+    ) {
+    }
 
-    if (myValue != 42 && myValue == 42) {}
+    if (myValue != 42 && myValue == 42) {
+    }
   }
 
   public void printSwitch() {
     switch (
       myValue == 42 ||
       (myValue == 42 && myValue == 42 && myValue == 42) ||
       (myValue == 42 && myValue == 42)
-    ) {}
+    ) {
+    }
 
     switch (
       (myValue != 42 && 42 / 42) ||
       (myValue & 42 && myValue > 42) ||
       (myValue < 42 && myValue == 42)
-    ) {}
+    ) {
+    }
 
-    switch (myValue != 42) {}
+    switch (myValue != 42) {
+    }
 
-    switch (myValue != 42 && myValue == 42) {}
+    switch (myValue != 42 && myValue == 42) {
+    }
   }
 
   public void printWhile() {

packages/prettier-plugin-java/test/unit-test/switch/_input.java

@@ -185,4 +185,14 @@ void switchRulesWithComments() {
         throw new RuntimeException();
     }
   }
+
+  void emptyBlocks() {
+    switch (a) {}
+    switch (a) {
+      case 1: {}
+    }
+    switch (a) {
+      case 1 -> {}
+    }
+  }
 }

packages/prettier-plugin-java/test/unit-test/switch/_output.java

@@ -55,8 +55,10 @@ public String shouldWrapEvenForSmallSwitchCases() {
 
   void switchCaseWithBlock1() {
     switch (a) {
-      case 0: {}
-      default: {}
+      case 0: {
+      }
+      default: {
+      }
     }
   }
 
@@ -233,4 +235,17 @@ void switchRulesWithComments() {
         throw new RuntimeException();
     }
   }
+
+  void emptyBlocks() {
+    switch (a) {
+    }
+    switch (a) {
+      case 1: {
+      }
+    }
+    switch (a) {
+      case 1 -> {
+      }
+    }
+  }
 }