Fix spaceBeforeSeparator in Jackson Gradle plugin (#2103)

Author: nedtwigg

CHANGES.md

@@ -21,6 +21,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Bump default `gson` version to latest `2.13.1` -> `2.13.2`. ([#2615](https://github.com/diffplug/spotless/pull/2615))
 * **BREAKING** Bump default `ktfmt` version to latest `0.53` -> `0.58` ([#2613](https://github.com/diffplug/spotless/pull/2613))
   * use `TrailingCommaManagementStrategy` enum instead of `manageTrailingCommas` boolean configuration option
+### Fixed
+* Fix `spaceBeforeSeparator` in Jackson formatter. ([#2103](https://github.com/diffplug/spotless/pull/2103))
 
 ## [3.3.1] - 2025-07-21
 ### Fixed

lib/src/jackson/java/com/diffplug/spotless/glue/json/JacksonJsonFormatterFunc.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021-2023 DiffPlug
+ * Copyright 2021-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,6 @@
 import com.fasterxml.jackson.core.JsonGenerator;
 import com.fasterxml.jackson.core.util.DefaultIndenter;
 import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
-import com.fasterxml.jackson.core.util.Separators;
 
 import com.diffplug.spotless.FormatterFunc;
 import com.diffplug.spotless.json.JacksonJsonConfig;
@@ -88,23 +87,23 @@ protected static class SpotlessJsonPrettyPrinter extends DefaultPrettyPrinter {
 
 		public SpotlessJsonPrettyPrinter(boolean spaceBeforeSeparator) {
 			this.spaceBeforeSeparator = spaceBeforeSeparator;
+
+			if (_objectFieldValueSeparatorWithSpaces == null || _objectFieldValueSeparatorWithSpaces.isEmpty()) {
+				return;
+			}
+
+			// Keep the behavior consistent even if Jackson changes default behavior
+			boolean startsWithSpace = Character.isWhitespace(_objectFieldValueSeparatorWithSpaces.charAt(0));
+			if (spaceBeforeSeparator && !startsWithSpace) {
+				_objectFieldValueSeparatorWithSpaces = String.format(" %s", _objectFieldValueSeparatorWithSpaces);
+			} else if (!spaceBeforeSeparator && startsWithSpace) {
+				_objectFieldValueSeparatorWithSpaces = _objectFieldValueSeparatorWithSpaces.substring(1);
+			}
 		}
 
 		@Override
 		public DefaultPrettyPrinter createInstance() {
 			return new SpotlessJsonPrettyPrinter(spaceBeforeSeparator);
 		}
-
-		@Override
-		public DefaultPrettyPrinter withSeparators(Separators separators) {
-			this._separators = separators;
-			if (spaceBeforeSeparator) {
-				// This is Jackson default behavior
-				this._objectFieldValueSeparatorWithSpaces = " " + separators.getObjectFieldValueSeparator() + " ";
-			} else {
-				this._objectFieldValueSeparatorWithSpaces = separators.getObjectFieldValueSeparator() + " ";
-			}
-			return this;
-		}
 	}
 }

plugin-gradle/CHANGES.md

@@ -17,6 +17,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ### Fixed
 * Respect system gitconfig when performing git operations ([#2404](https://github.com/diffplug/spotless/issues/2404))
+* Fix `spaceBeforeSeparator` in Jackson formatter. ([#2103](https://github.com/diffplug/spotless/pull/2103))
 * `spotlessInstallGitPrePushHook` is now compatible with configuration cache. ([#2570](https://github.com/diffplug/spotless/pull/2570))
 
 ## [7.2.1] - 2025-07-21

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java

@@ -168,6 +168,11 @@ public JacksonJsonGradleConfig jsonFeature(String feature, boolean toggle) {
 			return this;
 		}
 
+		public JacksonJsonGradleConfig setSpaceBeforeSeparator(boolean value) {
+			jacksonConfig.setSpaceBeforeSeparator(value);
+			return this;
+		}
+
 		@Override
 		public JacksonJsonGradleConfig self() {
 			return this;

plugin-maven/CHANGES.md

@@ -14,6 +14,8 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Bump default `gson` version to latest `2.13.1` -> `2.13.2`. ([#2615](https://github.com/diffplug/spotless/pull/2615))
 * **BREAKING** Bump default `ktfmt` version to latest `0.53` -> `0.58` ([#2613](https://github.com/diffplug/spotless/pull/2613))
   * use `TrailingCommaManagementStrategy` enum instead of `manageTrailingCommas` boolean configuration option
+### Fixed
+* Fix `spaceBeforeSeparator` in Jackson formatter. ([#2103](https://github.com/diffplug/spotless/pull/2103))
 
 ## [2.46.1] - 2025-07-21
 ### Fixed

testlib/src/main/resources/json/sortByKeysAfter_Jackson.json

@@ -1,19 +1,19 @@
 {
-  "A" : 1,
-  "X" : 2,
-  "_arraysNotSorted" : [ 3, 2, 1 ],
-  "_objectsInArraysAreSorted" : [ {
-    "a" : 1,
-    "b" : 2
+  "A": 1,
+  "X": 2,
+  "_arraysNotSorted": [ 3, 2, 1 ],
+  "_objectsInArraysAreSorted": [ {
+    "a": 1,
+    "b": 2
   } ],
-  "a" : 3,
-  "c" : 4,
-  "x" : 5,
-  "z" : {
-    "A" : 1,
-    "X" : 2,
-    "a" : 3,
-    "c" : 4,
-    "x" : 5
+  "a": 3,
+  "c": 4,
+  "x": 5,
+  "z": {
+    "A": 1,
+    "X": 2,
+    "a": 3,
+    "c": 4,
+    "x": 5
   }
 }