Don't merge two lines in formatter after line comment (KT-16032)

#KT-16032 Fixed

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/KotlinSpacingBuilder.kt

@@ -21,6 +21,7 @@ import com.intellij.formatting.DependentSpacingRule.Anchor
 import com.intellij.formatting.DependentSpacingRule.Trigger
 import com.intellij.lang.ASTNode
 import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiComment
 import com.intellij.psi.codeStyle.CommonCodeStyleSettings
 import com.intellij.psi.tree.IElementType
 import com.intellij.psi.tree.TokenSet
@@ -80,10 +81,12 @@ class KotlinSpacingBuilder(val commonCodeStyleSettings: CommonCodeStyleSettings,
 
         fun emptyLinesIfLineBreakInLeft(emptyLines: Int, numberOfLineFeedsOtherwise: Int = 1, numSpacesOtherwise: Int = 0) {
             newRule { parent: ASTBlock, left: ASTBlock, right: ASTBlock ->
+                val lastChild = left.node?.psi?.lastChild
+                val leftEndsWithComment = lastChild is PsiComment && lastChild.tokenType == KtTokens.EOL_COMMENT
                 val dependentSpacingRule = DependentSpacingRule(Trigger.HAS_LINE_FEEDS).registerData(Anchor.MIN_LINE_FEEDS, emptyLines + 1)
                 spacingBuilderUtil.createLineFeedDependentSpacing(numSpacesOtherwise,
                                                                   numSpacesOtherwise,
-                                                                  numberOfLineFeedsOtherwise,
+                                                                  if (leftEndsWithComment) Math.max(1, numberOfLineFeedsOtherwise) else numberOfLineFeedsOtherwise,
                                                                   commonCodeStyleSettings.KEEP_LINE_BREAKS,
                                                                   commonCodeStyleSettings.KEEP_BLANK_LINES_IN_DECLARATIONS,
                                                                   left.textRange,

idea/testData/formatter/EmptyLineBetweenEnumEntries.after.inv.kt

@@ -0,0 +1,33 @@
+enum class E1 { F, S, T }
+
+enum class E2 {
+    F, S, T
+}
+
+enum class E3 {
+    F, S, T
+}
+
+enum class E4 {
+    F {}, S, T
+}
+
+enum class E5 { F, S {}, T }
+
+enum class E6 {
+    F, S, T {}
+}
+
+enum class E7 {
+    F {
+
+    },
+    S, T
+}
+
+enum class E8 {
+    A, // A
+    B  // B
+}
+
+// SET_TRUE: KEEP_LINE_BREAKS

idea/testData/formatter/EmptyLineBetweenEnumEntries.after.kt

@@ -25,4 +25,11 @@ enum class E7 {
 
     },
     S, T
-}
+}
+
+enum class E8 {
+    A, // A
+    B  // B
+}
+
+// SET_TRUE: KEEP_LINE_BREAKS

idea/testData/formatter/EmptyLineBetweenEnumEntries.kt

@@ -22,4 +22,11 @@ enum class E7 {
     F {
 
     }, S, T
-}
+}
+
+enum class E8 {
+    A, // A
+    B  // B
+}
+
+// SET_TRUE: KEEP_LINE_BREAKS

idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java

@@ -986,6 +986,12 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             doTestInverted(fileName);
         }
 
+        @TestMetadata("EmptyLineBetweenEnumEntries.after.inv.kt")
+        public void testEmptyLineBetweenEnumEntries() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/EmptyLineBetweenEnumEntries.after.inv.kt");
+            doTestInverted(fileName);
+        }
+
         @TestMetadata("ForLineBreak.after.inv.kt")
         public void testForLineBreak() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/formatter/ForLineBreak.after.inv.kt");

idea/tests/org/jetbrains/kotlin/test/SettingsConfigurator.java

@@ -28,7 +28,7 @@ import java.util.Arrays;
 public class SettingsConfigurator {
     public static final String SET_TRUE_DIRECTIVE = "SET_TRUE:";
     public static final String SET_FALSE_DIRECTIVE = "SET_FALSE:";
-    public static final String SET_INT_DIRECTIVE = "SET_INT:";
+    private static final String SET_INT_DIRECTIVE = "SET_INT:";
 
     private final String[] settingsToTrue;
     private final String[] settingsToFalse;
@@ -54,7 +54,7 @@ public class SettingsConfigurator {
         this.objects = objects;
     }
 
-    public static void setSettingValue(String settingName, Object value, Class<?> valueType, Object... objects) {
+    private static void setSettingValue(String settingName, Object value, Class<?> valueType, Object... objects) {
         for (Object object : objects) {
             if (setSettingWithField(settingName, object, value) || setSettingWithMethod(settingName, object, value, valueType)) {
                 return;
@@ -65,11 +65,11 @@ public class SettingsConfigurator {
                 "There's no property or method with name '%s' in given objects: %s", settingName, Arrays.toString(objects)));
     }
 
-    public static void setBooleanSetting(String setting, Boolean value, Object... objects) {
+    private static void setBooleanSetting(String setting, Boolean value, Object... objects) {
         setSettingValue(setting, value, boolean.class, objects);
     }
 
-    public static void setIntSetting(String setting, Integer value, Object... objects) {
+    private static void setIntSetting(String setting, Integer value, Object... objects) {
         setSettingValue(setting, value, int.class, objects);
     }