YAML: Fix printing doubles a blank line before a comment

changelog_unreleased/yaml/pr-9143.md

@@ -0,0 +1,27 @@
+#### Fix printing doubles a blank line before a comment (#9143 by @sosukesuzuki)
+
+<!-- prettier-ignore -->
+```yaml
+# Input
+- foo: 0
+  bar: 1
+
+  # baz: 2
+- quux: 3
+
+# Prettier stable
+- foo: 0
+  bar: 1
+
+
+  # baz: 2
+- quux: 3
+
+# Prettier master
+- foo: 0
+  bar: 1
+
+  # baz: 2
+- quux: 3
+
+```

src/language-yaml/printer-yaml.js

@@ -127,8 +127,7 @@ function genericPrint(path, options, print) {
           ])
         )
       : "",
-    nextEmptyLine,
-    hasEndComments(node) && !isNode(node, ["documentHead", "documentBody"])
+    shouldPrintEndComments(node)
       ? align(
           node.type === "sequenceItem" ? 2 : 0,
           concat([
@@ -153,6 +152,7 @@ function genericPrint(path, options, print) {
           ])
         )
       : "",
+    nextEmptyLine,
   ]);
 }
 
@@ -703,6 +703,12 @@ function needsSpaceInFrontOfMappingValue(node) {
   return node.key.content && node.key.content.type === "alias";
 }
 
+function shouldPrintEndComments(node) {
+  return (
+    hasEndComments(node) && !isNode(node, ["documentHead", "documentBody"])
+  );
+}
+
 function printNextEmptyLine(path, originalText) {
   const node = path.getValue();
   const root = path.stack[0];
@@ -713,7 +719,9 @@ function printNextEmptyLine(path, originalText) {
   if (!root.isNextEmptyLinePrintedChecklist[node.position.end.line]) {
     if (isNextLineEmpty(node, originalText)) {
       root.isNextEmptyLinePrintedChecklist[node.position.end.line] = true;
-      return softline;
+      if (!shouldPrintEndComments(path.getParentNode())) {
+        return softline;
+      }
     }
   }
 

tests/yaml/comment/__snapshots__/jsfmt.spec.js.snap

@@ -137,6 +137,44 @@ printWidth: 80
 ================================================================================
 `;
 
+exports[`issue-9130.yml format 1`] = `
+====================================options=====================================
+parsers: ["yaml"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+- foo: 0
+  bar: 1
+
+  # baz: 2
+- quux: 3
+
+- foo: 0
+  bar: 1
+
+  # baz: 2
+
+  # baz: 3
+- quux: 3
+
+=====================================output=====================================
+- foo: 0
+  bar: 1
+
+  # baz: 2
+- quux: 3
+
+- foo: 0
+  bar: 1
+
+  # baz: 2
+
+  # baz: 3
+- quux: 3
+
+================================================================================
+`;
+
 exports[`map.yml format 1`] = `
 ====================================options=====================================
 parsers: ["yaml"]
@@ -282,6 +320,69 @@ foo2:
 ================================================================================
 `;
 
+exports[`map-4.yml format 1`] = `
+====================================options=====================================
+parsers: ["yaml"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+before:
+
+  # before.comment
+after:
+  # after.comment
+
+before-after:
+
+  # before-after.comment
+
+none:
+  # none.comment
+before(2 line):
+
+
+  # before.comment
+after(2 line):
+  # after.comment
+
+
+before-after(2 line):
+
+
+  # before-after.comment
+
+
+none(2):
+  # none.comment
+=====================================output=====================================
+before:
+
+# before.comment
+after:
+  # after.comment
+
+before-after:
+
+  # before-after.comment
+
+none:
+  # none.comment
+before(2 line):
+
+  # before.comment
+after(2 line):
+  # after.comment
+
+before-after(2 line):
+
+  # before-after.comment
+
+none(2):
+  # none.comment
+
+================================================================================
+`;
+
 exports[`object.yml format 1`] = `
 ====================================options=====================================
 parsers: ["yaml"]
@@ -336,6 +437,107 @@ printWidth: 80
 ================================================================================
 `;
 
+exports[`sequence.yml format 1`] = `
+====================================options=====================================
+parsers: ["yaml"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+-  - a
+
+   # - b
+
+   # - c
+
+   - e
+
+-  - a
+
+   # - b
+
+   # - c
+
+=====================================output=====================================
+- - a
+
+  # - b
+
+  # - c
+
+  - e
+
+- - a
+
+  # - b
+
+  # - c
+
+================================================================================
+`;
+
+exports[`sequence-2.yml format 1`] = `
+====================================options=====================================
+parsers: ["yaml"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+- before
+
+  # before.comment
+- after
+  # after.comment
+
+- before-after
+
+  # before-after.comment
+
+- none:
+  # none.comment
+- before(2 line)
+
+
+  # before.comment
+- after(2 line)
+  # after.comment
+
+
+- before-after(2 line)
+
+
+  # before-after.comment
+
+
+- none(2)
+  # none.comment
+=====================================output=====================================
+- before
+
+# before.comment
+- after
+  # after.comment
+
+- before-after
+
+  # before-after.comment
+
+- none:
+  # none.comment
+- before(2 line)
+
+  # before.comment
+- after(2 line)
+  # after.comment
+
+- before-after(2 line)
+
+  # before-after.comment
+
+- none(2)
+  # none.comment
+
+================================================================================
+`;
+
 exports[`set.yml format 1`] = `
 ====================================options=====================================
 parsers: ["yaml"]

tests/yaml/comment/issue-9130.yml

@@ -0,0 +1,13 @@
+- foo: 0
+  bar: 1
+
+  # baz: 2
+- quux: 3
+
+- foo: 0
+  bar: 1
+
+  # baz: 2
+
+  # baz: 3
+- quux: 3

tests/yaml/comment/map-4.yml

@@ -0,0 +1,28 @@
+before:
+
+  # before.comment
+after:
+  # after.comment
+
+before-after:
+
+  # before-after.comment
+
+none:
+  # none.comment
+before(2 line):
+
+
+  # before.comment
+after(2 line):
+  # after.comment
+
+
+before-after(2 line):
+
+
+  # before-after.comment
+
+
+none(2):
+  # none.comment

tests/yaml/comment/sequence-2.yml

@@ -0,0 +1,28 @@
+- before
+
+  # before.comment
+- after
+  # after.comment
+
+- before-after
+
+  # before-after.comment
+
+- none:
+  # none.comment
+- before(2 line)
+
+
+  # before.comment
+- after(2 line)
+  # after.comment
+
+
+- before-after(2 line)
+
+
+  # before-after.comment
+
+
+- none(2)
+  # none.comment

tests/yaml/comment/sequence.yml

@@ -0,0 +1,13 @@
+-  - a
+
+   # - b
+
+   # - c
+
+   - e
+
+-  - a
+
+   # - b
+
+   # - c