From 76b626cc73ef469c499a3b5fc33f807c0645766f Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Wed, 25 Jan 2023 22:29:12 +0400
Subject: [PATCH 01/10] Handle specifically empty filePath, and not default FS
 rootDir

---
 gradle.properties                             |  2 +-
 .../java/com/diffplug/spotless/Formatter.java | 12 +++-
 testlib/build.gradle                          |  1 +
 .../com/diffplug/spotless/FormatterTest.java  | 66 ++++++++++++++++++-
 4 files changed, 76 insertions(+), 5 deletions(-)

diff --git a/gradle.properties b/gradle.properties
index 5702d21bdd..523440be25 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -28,4 +28,4 @@ VER_DURIAN=1.2.0
 VER_JGIT=5.13.1.202206130422-r
 VER_JUNIT=5.9.2
 VER_ASSERTJ=3.24.2
-VER_MOCKITO=4.11.0
\ No newline at end of file
+VER_MOCKITO=5.0.0
diff --git a/lib/src/main/java/com/diffplug/spotless/Formatter.java b/lib/src/main/java/com/diffplug/spotless/Formatter.java
index 038e77fa64..3a38893cd6 100644
--- a/lib/src/main/java/com/diffplug/spotless/Formatter.java
+++ b/lib/src/main/java/com/diffplug/spotless/Formatter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -237,8 +237,14 @@ public String compute(String unix, File file) {
 					unix = LineEnding.toUnix(formatted);
 				}
 			} catch (Throwable e) {
-				String relativePath = rootDir.relativize(file.toPath()).toString();
-				exceptionPolicy.handleError(e, step, relativePath);
+				if (file.getPath().isEmpty()) {
+					// Path.relativize would fail if rootDir is an absolute path
+					exceptionPolicy.handleError(e, step, "");
+				} else {
+					// Path may be forged from a different FileSystem than Filesystem.default
+					String relativePath = rootDir.relativize(rootDir.getFileSystem().getPath(file.getPath())).toString();
+					exceptionPolicy.handleError(e, step, relativePath);
+				}
 			}
 		}
 		return unix;
diff --git a/testlib/build.gradle b/testlib/build.gradle
index 64d4681805..97b17d0dc6 100644
--- a/testlib/build.gradle
+++ b/testlib/build.gradle
@@ -12,6 +12,7 @@ dependencies {
 	api "com.diffplug.durian:durian-testlib:${VER_DURIAN}"
 	api "org.junit.jupiter:junit-jupiter:${VER_JUNIT}"
 	api "org.assertj:assertj-core:${VER_ASSERTJ}"
+	api "org.mockito:mockito-core:$VER_MOCKITO"
 
 	implementation "com.diffplug.durian:durian-io:${VER_DURIAN}"
 	implementation "com.diffplug.durian:durian-collect:${VER_DURIAN}"
diff --git a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
index 06b8e64d31..0faf40bb95 100644
--- a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,15 +15,19 @@
  */
 package com.diffplug.spotless;
 
+import java.io.File;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystems;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
 
 import com.diffplug.common.base.StandardSystemProperty;
 import com.diffplug.spotless.generic.EndWithNewlineStep;
@@ -89,4 +93,64 @@ protected Formatter create() {
 			}
 		}.testEquals();
 	}
+
+	// new File("") can be used if there is no File representing this content. It should not conflict with rootDir.relativize(...)
+	@Test
+	public void testExceptionWithEmptyPath() throws Exception {
+		LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX.createPolicy();
+		Charset encoding = StandardCharsets.UTF_8;
+		FormatExceptionPolicy exceptionPolicy = FormatExceptionPolicy.failOnlyOnError();
+
+		Path rootDir = Paths.get(StandardSystemProperty.USER_DIR.value());
+
+		FormatterStep step = Mockito.mock(FormatterStep.class);
+		Mockito.when(step.getName()).thenReturn("someFailingStep");
+		Mockito.when(step.format(Mockito.anyString(), Mockito.any(File.class))).thenThrow(new IllegalArgumentException("someReason"));
+		List<FormatterStep> steps = Collections.singletonList(step);
+
+		Formatter formatter = Formatter.builder()
+				.lineEndingsPolicy(lineEndingsPolicy)
+				.encoding(encoding)
+				.rootDir(rootDir)
+				.steps(steps)
+				.exceptionPolicy(exceptionPolicy)
+				.build();
+
+		formatter.compute("someFileContent", new File(""));
+	}
+
+	// rootDir may be a path not from the default FileSystem
+	@Test
+	public void testExceptionWithRootDirIsNotFileSystem() throws Exception {
+		LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX.createPolicy();
+		Charset encoding = StandardCharsets.UTF_8;
+		FormatExceptionPolicy exceptionPolicy = FormatExceptionPolicy.failOnlyOnError();
+
+		Path rootDir = Mockito.mock(Path.class);
+		Path relativized = Mockito.mock(Path.class);
+		Mockito.when(rootDir.relativize(Mockito.any(Path.class))).then(invok -> {
+			Path filePath = invok.getArgument(0);
+			if (filePath.getFileSystem() == FileSystems.getDefault()) {
+				throw new IllegalArgumentException("Can not relativize through different FileSystems");
+			}
+
+			return relativized;
+		});
+
+		FormatterStep step = Mockito.mock(FormatterStep.class);
+		Mockito.when(step.getName()).thenReturn("someFailingStep");
+		Mockito.when(step.format(Mockito.anyString(), Mockito.any(File.class))).thenThrow(new IllegalArgumentException("someReason"));
+		List<FormatterStep> steps = Collections.singletonList(step);
+
+		Formatter formatter = Formatter.builder()
+				.lineEndingsPolicy(lineEndingsPolicy)
+				.encoding(encoding)
+				.rootDir(rootDir)
+				.steps(steps)
+				.exceptionPolicy(exceptionPolicy)
+				.build();
+
+		formatter.compute("someFileContent", new File(""));
+	}
+
 }

From a8c0bb818de07242feeb08f5731af6ce6fd7a0cb Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Wed, 25 Jan 2023 22:53:07 +0400
Subject: [PATCH 02/10] Rollback Mockito to 4.X (as 5.X requires JDK11)

---
 gradle.properties | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gradle.properties b/gradle.properties
index 523440be25..d99bdac6ce 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -28,4 +28,4 @@ VER_DURIAN=1.2.0
 VER_JGIT=5.13.1.202206130422-r
 VER_JUNIT=5.9.2
 VER_ASSERTJ=3.24.2
-VER_MOCKITO=5.0.0
+VER_MOCKITO=4.11.0

From 0d34fa703536b7f83b35d45f7eea153d724e2cc3 Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Thu, 26 Jan 2023 23:20:30 +0400
Subject: [PATCH 03/10] Switch from new File() to a Sentinel reference

---
 .../java/com/diffplug/spotless/Formatter.java |  6 ++-
 .../com/diffplug/spotless/FormatterStep.java  |  6 +--
 .../diffplug/spotless/FormatterStepImpl.java  |  9 ++---
 .../com/diffplug/spotless/FormatterTest.java  | 38 +++++++++++++++++--
 4 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/Formatter.java b/lib/src/main/java/com/diffplug/spotless/Formatter.java
index 3a38893cd6..be045e7fe1 100644
--- a/lib/src/main/java/com/diffplug/spotless/Formatter.java
+++ b/lib/src/main/java/com/diffplug/spotless/Formatter.java
@@ -39,6 +39,9 @@
 public final class Formatter implements Serializable, AutoCloseable {
 	private static final long serialVersionUID = 1L;
 
+	// This Sentinel reference may be used where Formatter requires a File, while there is no actual File to format
+	public static final File SENTINEL_NO_FILE_ON_DISK = new File("NO_FILE_ON_DISK.sentinel");
+
 	private LineEnding.Policy lineEndingsPolicy;
 	private Charset encoding;
 	private Path rootDir;
@@ -237,8 +240,7 @@ public String compute(String unix, File file) {
 					unix = LineEnding.toUnix(formatted);
 				}
 			} catch (Throwable e) {
-				if (file.getPath().isEmpty()) {
-					// Path.relativize would fail if rootDir is an absolute path
+				if (file == SENTINEL_NO_FILE_ON_DISK) {
 					exceptionPolicy.handleError(e, step, "");
 				} else {
 					// Path may be forged from a different FileSystem than Filesystem.default
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
index 5729f676b2..79793a403e 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,8 +37,8 @@ public interface FormatterStep extends Serializable {
 	 * @param rawUnix
 	 *            the content to format, guaranteed to have unix-style newlines ('\n'); never null
 	 * @param file
-	 *            the file which {@code rawUnix} was obtained from; never null. Pass an empty file using
-	 *            {@code new File("")} if and only if no file is actually associated with {@code rawUnix}
+	 *            the file which {@code rawUnix} was obtained from; never null. Pass the reference
+	 *            {@code Formatter#SENTINEL_NO_FILE_ON_DISK} if and only if no file is actually associated with {@code rawUnix}
 	 * @return the formatted content, guaranteed to only have unix-style newlines; may return null
 	 *         if the formatter step doesn't have any changes to make
 	 * @throws Exception if the formatter step experiences a problem
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
index 7663145f51..fe7cabca49 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2022 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -109,18 +109,15 @@ protected String format(Integer state, String rawUnix, File file) throws Excepti
 			if (formatter == null) {
 				formatter = formatterSupplier.get();
 				if (formatter instanceof FormatterFunc.Closeable) {
-					throw new AssertionError("NeverUpToDate does not support FormatterFunc.Closeable.  See https://github.com/diffplug/spotless/pull/284");
+					throw new AssertionError("NeverUpToDate does not support FormatterFunc.Closeable. See https://github.com/diffplug/spotless/pull/284");
 				}
 			}
 			return formatter.apply(rawUnix, file);
 		}
 	}
 
-	/** A dummy SENTINEL file. */
-	static final File SENTINEL = new File("");
-
 	static void checkNotSentinel(File file) {
-		if (file == SENTINEL) {
+		if (file == Formatter.SENTINEL_NO_FILE_ON_DISK) {
 			throw new IllegalArgumentException("This step requires the underlying file. If this is a test, use StepHarnessWithFile");
 		}
 	}
diff --git a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
index 0faf40bb95..de96cd2ae3 100644
--- a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
@@ -18,6 +18,7 @@
 import java.io.File;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystem;
 import java.nio.file.FileSystems;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -94,7 +95,7 @@ protected Formatter create() {
 		}.testEquals();
 	}
 
-	// new File("") can be used if there is no File representing this content. It should not conflict with rootDir.relativize(...)
+	// new File("") as filePath is known to fail
 	@Test
 	public void testExceptionWithEmptyPath() throws Exception {
 		LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX.createPolicy();
@@ -116,7 +117,32 @@ public void testExceptionWithEmptyPath() throws Exception {
 				.exceptionPolicy(exceptionPolicy)
 				.build();
 
-		formatter.compute("someFileContent", new File(""));
+		Assertions.assertThrows(IllegalArgumentException.class, () -> formatter.compute("someFileContent", new File("")));
+	}
+
+	// If there is no File actually holding the content, one may rely on Formatter.NO_FILE_ON_DISK
+	@Test
+	public void testExceptionWithSentinelNoFileOnDisk() throws Exception {
+		LineEnding.Policy lineEndingsPolicy = LineEnding.UNIX.createPolicy();
+		Charset encoding = StandardCharsets.UTF_8;
+		FormatExceptionPolicy exceptionPolicy = FormatExceptionPolicy.failOnlyOnError();
+
+		Path rootDir = Paths.get(StandardSystemProperty.USER_DIR.value());
+
+		FormatterStep step = Mockito.mock(FormatterStep.class);
+		Mockito.when(step.getName()).thenReturn("someFailingStep");
+		Mockito.when(step.format(Mockito.anyString(), Mockito.any(File.class))).thenThrow(new IllegalArgumentException("someReason"));
+		List<FormatterStep> steps = Collections.singletonList(step);
+
+		Formatter formatter = Formatter.builder()
+				.lineEndingsPolicy(lineEndingsPolicy)
+				.encoding(encoding)
+				.rootDir(rootDir)
+				.steps(steps)
+				.exceptionPolicy(exceptionPolicy)
+				.build();
+
+		formatter.compute("someFileContent", Formatter.SENTINEL_NO_FILE_ON_DISK);
 	}
 
 	// rootDir may be a path not from the default FileSystem
@@ -127,6 +153,12 @@ public void testExceptionWithRootDirIsNotFileSystem() throws Exception {
 		FormatExceptionPolicy exceptionPolicy = FormatExceptionPolicy.failOnlyOnError();
 
 		Path rootDir = Mockito.mock(Path.class);
+		FileSystem customFileSystem = Mockito.mock(FileSystem.class);
+		Mockito.when(rootDir.getFileSystem()).thenReturn(customFileSystem);
+
+		Path pathFromFile = Mockito.mock(Path.class);
+		Mockito.when(customFileSystem.getPath(Mockito.anyString())).thenReturn(pathFromFile);
+
 		Path relativized = Mockito.mock(Path.class);
 		Mockito.when(rootDir.relativize(Mockito.any(Path.class))).then(invok -> {
 			Path filePath = invok.getArgument(0);
@@ -150,7 +182,7 @@ public void testExceptionWithRootDirIsNotFileSystem() throws Exception {
 				.exceptionPolicy(exceptionPolicy)
 				.build();
 
-		formatter.compute("someFileContent", new File(""));
+		formatter.compute("someFileContent", new File("/some/folder/some.file"));
 	}
 
 }

From dbea734458f3323cf121f84744838fa865c1a1a6 Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Thu, 26 Jan 2023 23:33:27 +0400
Subject: [PATCH 04/10] Refactor mire usages

---
 lib/src/main/java/com/diffplug/spotless/FormatterFunc.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
index 48a8e810ee..8a8a15076e 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
@@ -127,7 +127,7 @@ public String apply(String unix, File file) throws Exception {
 
 				@Override
 				public String apply(String unix) throws Exception {
-					return apply(unix, FormatterStepImpl.SENTINEL);
+					return apply(unix, Formatter.SENTINEL_NO_FILE_ON_DISK);
 				}
 			};
 		}
@@ -156,7 +156,7 @@ default String apply(String unix, File file) throws Exception {
 
 		@Override
 		default String apply(String unix) throws Exception {
-			return apply(unix, FormatterStepImpl.SENTINEL);
+			return apply(unix, Formatter.SENTINEL_NO_FILE_ON_DISK);
 		}
 	}
 }

From 378a4e8e7f022320b4f0d26844ff390025ee0992 Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Thu, 26 Jan 2023 23:39:00 +0400
Subject: [PATCH 05/10] Fix style

---
 lib/src/main/java/com/diffplug/spotless/FormatterFunc.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
index 8a8a15076e..90d576e8a0 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

From 4439934095209a332a8b1cfe1037756cbe878108 Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Thu, 26 Jan 2023 23:48:21 +0400
Subject: [PATCH 06/10] Rely on existing Sentinel

---
 lib/src/main/java/com/diffplug/spotless/Formatter.java     | 5 +----
 lib/src/main/java/com/diffplug/spotless/FormatterFunc.java | 6 +++---
 lib/src/main/java/com/diffplug/spotless/FormatterStep.java | 2 +-
 .../main/java/com/diffplug/spotless/FormatterStepImpl.java | 7 +++++--
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/Formatter.java b/lib/src/main/java/com/diffplug/spotless/Formatter.java
index be045e7fe1..035452e29c 100644
--- a/lib/src/main/java/com/diffplug/spotless/Formatter.java
+++ b/lib/src/main/java/com/diffplug/spotless/Formatter.java
@@ -39,9 +39,6 @@
 public final class Formatter implements Serializable, AutoCloseable {
 	private static final long serialVersionUID = 1L;
 
-	// This Sentinel reference may be used where Formatter requires a File, while there is no actual File to format
-	public static final File SENTINEL_NO_FILE_ON_DISK = new File("NO_FILE_ON_DISK.sentinel");
-
 	private LineEnding.Policy lineEndingsPolicy;
 	private Charset encoding;
 	private Path rootDir;
@@ -240,7 +237,7 @@ public String compute(String unix, File file) {
 					unix = LineEnding.toUnix(formatted);
 				}
 			} catch (Throwable e) {
-				if (file == SENTINEL_NO_FILE_ON_DISK) {
+				if (file == FormatterStepImpl.SENTINEL) {
 					exceptionPolicy.handleError(e, step, "");
 				} else {
 					// Path may be forged from a different FileSystem than Filesystem.default
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
index 90d576e8a0..48a8e810ee 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2021 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -127,7 +127,7 @@ public String apply(String unix, File file) throws Exception {
 
 				@Override
 				public String apply(String unix) throws Exception {
-					return apply(unix, Formatter.SENTINEL_NO_FILE_ON_DISK);
+					return apply(unix, FormatterStepImpl.SENTINEL);
 				}
 			};
 		}
@@ -156,7 +156,7 @@ default String apply(String unix, File file) throws Exception {
 
 		@Override
 		default String apply(String unix) throws Exception {
-			return apply(unix, Formatter.SENTINEL_NO_FILE_ON_DISK);
+			return apply(unix, FormatterStepImpl.SENTINEL);
 		}
 	}
 }
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
index 79793a403e..11a4d5f99e 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
@@ -38,7 +38,7 @@ public interface FormatterStep extends Serializable {
 	 *            the content to format, guaranteed to have unix-style newlines ('\n'); never null
 	 * @param file
 	 *            the file which {@code rawUnix} was obtained from; never null. Pass the reference
-	 *            {@code Formatter#SENTINEL_NO_FILE_ON_DISK} if and only if no file is actually associated with {@code rawUnix}
+	 *            {@code FormatterStepImpl#SENTINEL} if and only if no file is actually associated with {@code rawUnix}
 	 * @return the formatted content, guaranteed to only have unix-style newlines; may return null
 	 *         if the formatter step doesn't have any changes to make
 	 * @throws Exception if the formatter step experiences a problem
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
index fe7cabca49..3b1b5cf278 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
@@ -109,15 +109,18 @@ protected String format(Integer state, String rawUnix, File file) throws Excepti
 			if (formatter == null) {
 				formatter = formatterSupplier.get();
 				if (formatter instanceof FormatterFunc.Closeable) {
-					throw new AssertionError("NeverUpToDate does not support FormatterFunc.Closeable. See https://github.com/diffplug/spotless/pull/284");
+					throw new AssertionError("NeverUpToDate does not support FormatterFunc.Closeable.  See https://github.com/diffplug/spotless/pull/284");
 				}
 			}
 			return formatter.apply(rawUnix, file);
 		}
 	}
 
+	/**This Sentinel reference may be used where Formatter requires a File, while there is no actual File to format */
+	public static final File SENTINEL = new File("");
+
 	static void checkNotSentinel(File file) {
-		if (file == Formatter.SENTINEL_NO_FILE_ON_DISK) {
+		if (file == SENTINEL) {
 			throw new IllegalArgumentException("This step requires the underlying file. If this is a test, use StepHarnessWithFile");
 		}
 	}

From 7f7cc49fed67ea9b8fc5706427dfc16c830570e0 Mon Sep 17 00:00:00 2001
From: Benoit Lacelle <benoit.lacelle@gmail.com>
Date: Thu, 26 Jan 2023 23:54:13 +0400
Subject: [PATCH 07/10] Fix compilation

---
 testlib/src/test/java/com/diffplug/spotless/FormatterTest.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
index de96cd2ae3..76f11b3d15 100644
--- a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
@@ -142,7 +142,7 @@ public void testExceptionWithSentinelNoFileOnDisk() throws Exception {
 				.exceptionPolicy(exceptionPolicy)
 				.build();
 
-		formatter.compute("someFileContent", Formatter.SENTINEL_NO_FILE_ON_DISK);
+		formatter.compute("someFileContent", FormatterStepImpl.SENTINEL);
 	}
 
 	// rootDir may be a path not from the default FileSystem

From 07a57ff66f3fa0ffd8abea94e7c0f6ac4f025b5f Mon Sep 17 00:00:00 2001
From: Ned Twigg <ned.twigg@diffplug.com>
Date: Thu, 26 Jan 2023 12:18:26 -0800
Subject: [PATCH 08/10] Rename the sentinel and move it to `Formatter`.

---
 lib/src/main/java/com/diffplug/spotless/Formatter.java      | 5 ++++-
 lib/src/main/java/com/diffplug/spotless/FormatterFunc.java  | 6 +++---
 .../main/java/com/diffplug/spotless/FormatterStepImpl.java  | 5 +----
 .../src/main/java/com/diffplug/spotless/StepHarness.java    | 2 +-
 .../src/test/java/com/diffplug/spotless/FormatterTest.java  | 2 +-
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/Formatter.java b/lib/src/main/java/com/diffplug/spotless/Formatter.java
index 035452e29c..a55e8e6504 100644
--- a/lib/src/main/java/com/diffplug/spotless/Formatter.java
+++ b/lib/src/main/java/com/diffplug/spotless/Formatter.java
@@ -237,7 +237,7 @@ public String compute(String unix, File file) {
 					unix = LineEnding.toUnix(formatted);
 				}
 			} catch (Throwable e) {
-				if (file == FormatterStepImpl.SENTINEL) {
+				if (file == NO_FILE_SENTINEL) {
 					exceptionPolicy.handleError(e, step, "");
 				} else {
 					// Path may be forged from a different FileSystem than Filesystem.default
@@ -289,4 +289,7 @@ public void close() {
 			}
 		}
 	}
+
+	/** This Sentinel reference may be used to  Formatter requires a File, while there is no actual File to format */
+	public static final File NO_FILE_SENTINEL = new File("NO_FILE_SENTINEL");
 }
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
index 48a8e810ee..14b407a2eb 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterFunc.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -127,7 +127,7 @@ public String apply(String unix, File file) throws Exception {
 
 				@Override
 				public String apply(String unix) throws Exception {
-					return apply(unix, FormatterStepImpl.SENTINEL);
+					return apply(unix, Formatter.NO_FILE_SENTINEL);
 				}
 			};
 		}
@@ -156,7 +156,7 @@ default String apply(String unix, File file) throws Exception {
 
 		@Override
 		default String apply(String unix) throws Exception {
-			return apply(unix, FormatterStepImpl.SENTINEL);
+			return apply(unix, Formatter.NO_FILE_SENTINEL);
 		}
 	}
 }
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
index 3b1b5cf278..17b62e75c6 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStepImpl.java
@@ -116,11 +116,8 @@ protected String format(Integer state, String rawUnix, File file) throws Excepti
 		}
 	}
 
-	/**This Sentinel reference may be used where Formatter requires a File, while there is no actual File to format */
-	public static final File SENTINEL = new File("");
-
 	static void checkNotSentinel(File file) {
-		if (file == SENTINEL) {
+		if (file == Formatter.NO_FILE_SENTINEL) {
 			throw new IllegalArgumentException("This step requires the underlying file. If this is a test, use StepHarnessWithFile");
 		}
 	}
diff --git a/testlib/src/main/java/com/diffplug/spotless/StepHarness.java b/testlib/src/main/java/com/diffplug/spotless/StepHarness.java
index 71e2a663b5..c611cc738a 100644
--- a/testlib/src/main/java/com/diffplug/spotless/StepHarness.java
+++ b/testlib/src/main/java/com/diffplug/spotless/StepHarness.java
@@ -88,7 +88,7 @@ public AbstractStringAssert<?> testResourceExceptionMsg(String resourceBefore) {
 
 	public AbstractStringAssert<?> testExceptionMsg(String before) {
 		try {
-			formatter.compute(LineEnding.toUnix(before), FormatterStepImpl.SENTINEL);
+			formatter.compute(LineEnding.toUnix(before), Formatter.NO_FILE_SENTINEL);
 			throw new SecurityException("Expected exception");
 		} catch (Throwable e) {
 			if (e instanceof SecurityException) {
diff --git a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
index 76f11b3d15..314507bd8d 100644
--- a/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/FormatterTest.java
@@ -142,7 +142,7 @@ public void testExceptionWithSentinelNoFileOnDisk() throws Exception {
 				.exceptionPolicy(exceptionPolicy)
 				.build();
 
-		formatter.compute("someFileContent", FormatterStepImpl.SENTINEL);
+		formatter.compute("someFileContent", Formatter.NO_FILE_SENTINEL);
 	}
 
 	// rootDir may be a path not from the default FileSystem

From 9adce647c6dd3e605ddc555c5a972f32d9b192d4 Mon Sep 17 00:00:00 2001
From: Ned Twigg <ned.twigg@diffplug.com>
Date: Thu, 26 Jan 2023 12:25:17 -0800
Subject: [PATCH 09/10] Fix javadoc.

---
 lib/src/main/java/com/diffplug/spotless/Formatter.java     | 2 +-
 lib/src/main/java/com/diffplug/spotless/FormatterStep.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/src/main/java/com/diffplug/spotless/Formatter.java b/lib/src/main/java/com/diffplug/spotless/Formatter.java
index a55e8e6504..3470a3dc69 100644
--- a/lib/src/main/java/com/diffplug/spotless/Formatter.java
+++ b/lib/src/main/java/com/diffplug/spotless/Formatter.java
@@ -290,6 +290,6 @@ public void close() {
 		}
 	}
 
-	/** This Sentinel reference may be used to  Formatter requires a File, while there is no actual File to format */
+	/** This Sentinel reference may be used to pass string content to a Formatter or FormatterStep when there is no actual File to format */
 	public static final File NO_FILE_SENTINEL = new File("NO_FILE_SENTINEL");
 }
diff --git a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
index 11a4d5f99e..ce09f68450 100644
--- a/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/FormatterStep.java
@@ -38,7 +38,7 @@ public interface FormatterStep extends Serializable {
 	 *            the content to format, guaranteed to have unix-style newlines ('\n'); never null
 	 * @param file
 	 *            the file which {@code rawUnix} was obtained from; never null. Pass the reference
-	 *            {@code FormatterStepImpl#SENTINEL} if and only if no file is actually associated with {@code rawUnix}
+	 *            {@link Formatter#NO_FILE_SENTINEL} if and only if no file is actually associated with {@code rawUnix}
 	 * @return the formatted content, guaranteed to only have unix-style newlines; may return null
 	 *         if the formatter step doesn't have any changes to make
 	 * @throws Exception if the formatter step experiences a problem

From 1f78affc868f275b92ad3db7aa9eb7ab3416c16d Mon Sep 17 00:00:00 2001
From: Ned Twigg <ned.twigg@diffplug.com>
Date: Thu, 26 Jan 2023 12:28:40 -0800
Subject: [PATCH 10/10] Update changelog.

---
 CHANGES.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 22e568f566..2af0ab7090 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,6 +10,8 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Added
+* `Formatter` now has a field `public static final File NO_FILE_SENTINEL` which can be used to pass string content to a Formatter or FormatterStep when there is no actual File to format. ([#1525](https://github.com/diffplug/spotless/pull/1525))
 
 ## [2.33.0] - 2023-01-26
 ### Added