diff --git a/CHANGES.md b/CHANGES.md
index d3bb7eacf1..c9825f6de4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -15,6 +15,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ### Changes
 * Bump default `ktlint` version to latest `1.7.1` -> `1.8.0`. ([2763](https://github.com/diffplug/spotless/pull/2763))
 * Bump default `gherkin-utils` version to latest `9.2.0` -> `10.0.0`. ([#2619](https://github.com/diffplug/spotless/pull/2619))
+- Fix null pointer exception when git ignored files are checked in ([911](https://github.com/diffplug/spotless/issues/911))
 
 ## [4.1.0] - 2025-11-18
 ### Changes
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/GitRatchet.java b/lib-extra/src/main/java/com/diffplug/spotless/extra/GitRatchet.java
index f30e8fd002..3d90fcc9e4 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/GitRatchet.java
+++ b/lib-extra/src/main/java/com/diffplug/spotless/extra/GitRatchet.java
@@ -97,8 +97,14 @@ public boolean isClean(Project project, ObjectId treeSha, String relativePathUni
 				WorkingTreeIterator workingTreeIterator = treeWalk.getTree(WORKDIR, WorkingTreeIterator.class);
 
 				boolean hasTree = treeIterator != null;
+				boolean hasWorkingTree = workingTreeIterator != null;
 				boolean hasDirCache = dirCacheIterator != null;
 
+				if (!hasWorkingTree) {
+					// Null check for issue 911
+					return true;
+				}
+
 				if (!hasTree) {
 					// it's not in the tree, so it was added
 					return false;
diff --git a/plugin-gradle/CHANGES.md b/plugin-gradle/CHANGES.md
index 76832c1b22..bd3d1968d4 100644
--- a/plugin-gradle/CHANGES.md
+++ b/plugin-gradle/CHANGES.md
@@ -8,6 +8,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ### Changes
 * Bump default `ktlint` version to latest `1.7.1` -> `1.8.0`. ([2763](https://github.com/diffplug/spotless/pull/2763))
 * Bump default `gherkin-utils` version to latest `9.2.0` -> `10.0.0`. ([#2619](https://github.com/diffplug/spotless/pull/2619))
+- Fix null pointer exception when git ignored files are checked in ([911](https://github.com/diffplug/spotless/issues/911))
 
 ## [8.1.0] - 2025-11-18
 ### Changes
diff --git a/plugin-maven/CHANGES.md b/plugin-maven/CHANGES.md
index 6be35513a3..fca279729d 100644
--- a/plugin-maven/CHANGES.md
+++ b/plugin-maven/CHANGES.md
@@ -8,6 +8,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ### Changes
 * Bump default `ktlint` version to latest `1.7.1` -> `1.8.0`. ([2763](https://github.com/diffplug/spotless/pull/2763))
 * Bump default `gherkin-utils` version to latest `9.2.0` -> `10.0.0`. ([#2619](https://github.com/diffplug/spotless/pull/2619))
+- Fix null pointer exception when git ignored files are checked in ([911](https://github.com/diffplug/spotless/issues/911))
 
 ## [3.1.0] - 2025-11-18
 ### Changes