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feat: Implement conversion of diff content to ReviewDog format #2478

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Original file line number Diff line number Diff line change
@@ -0,0 +1,165 @@
/*
* Copyright 2022-2025 DiffPlug
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.diffplug.spotless.extra.middleware;

import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

import com.diffplug.spotless.FormatterStep;
import com.diffplug.spotless.Lint;

/**
* Utility class for generating ReviewDog compatible output in the rdjsonl format.
* This class provides methods to create diff and lint reports that can be used by ReviewDog.
*/
public final class ReviewDogGenerator {

private static final String SOURCE = "spotless";

private ReviewDogGenerator() {
// Prevent instantiation
}

/**
* Generates a ReviewDog compatible JSON line (rdjsonl) for a diff between
* the actual content and the formatted content of a file.
*
* @param path The file path
* @param actualContent The content as it currently exists in the file
* @param formattedContent The content after formatting is applied
* @return A string in rdjsonl format representing the diff
*/
public static String rdjsonlDiff(String path, String actualContent, String formattedContent) {
if (actualContent.equals(formattedContent)) {
return "";
}

String diff = createUnifiedDiff(path, actualContent, formattedContent);

return String.format(
"{\"message\":{\"path\":\"%s\",\"message\":\"File requires formatting\",\"diff\":\"%s\"}}",
escapeJson(path),
escapeJson(diff));
}

/**
* Generates ReviewDog compatible JSON lines (rdjsonl) for lint issues
* identified by formatting steps.
*
* @param path The file path
* @param steps The list of formatter steps applied
* @param lintsPerStep The list of lints produced by each step
* @return A string in rdjsonl format representing the lints
*/
public static String rdjsonlLintsFromSteps(String path, List<FormatterStep> steps, List<List<Lint>> lintsPerStep) {
if (steps == null || steps.isEmpty()) {
return rdjsonlLintsFromStrings(path, Collections.emptyList(), lintsPerStep);
}
List<String> stepNames = steps.stream()
.map(FormatterStep::getName)
.collect(Collectors.toList());

if (lintsPerStep == null || lintsPerStep.isEmpty()) {
return rdjsonlLintsFromStrings(path, stepNames, Collections.emptyList());
}
return rdjsonlLintsFromStrings(path, stepNames, lintsPerStep);
}

private static String rdjsonlLintsFromStrings(String path, List<String> stepNames, List<List<Lint>> lintsPerStep) {
if (lintsPerStep == null || lintsPerStep.isEmpty()) {
return "";
}

StringBuilder builder = new StringBuilder();

for (int i = 0; i < lintsPerStep.size(); i++) {
List<Lint> lints = lintsPerStep.get(i);
if (lints == null || lints.isEmpty()) {
continue;
}

String stepName = (i < stepNames.size()) ? stepNames.get(i) : "unknown";
for (Lint lint : lints) {
builder.append(formatLintAsJson(path, lint, stepName)).append('\n');
}
}

return builder.toString().trim();
}

/**
* Creates a unified diff between two text contents.
*/
private static String createUnifiedDiff(String path, String actualContent, String formattedContent) {
String[] actualLines = actualContent.split("\\r?\\n", -1);
String[] formattedLines = formattedContent.split("\\r?\\n", -1);

StringBuilder diff = new StringBuilder();
diff.append("--- a/").append(path).append('\n');
diff.append("+++ b/").append(path).append('\n');
diff.append("@@ -1,").append(actualLines.length).append(" +1,").append(formattedLines.length).append(" @@\n");

for (String line : actualLines) {
diff.append('-').append(line).append('\n');
}

for (String line : formattedLines) {
diff.append('+').append(line).append('\n');
}

return diff.toString();
}

/**
* Formats a single lint issue as a JSON line.
*/
private static String formatLintAsJson(String path, Lint lint, String ruleCode) {
return String.format(
"{"
+ "\"source\":\"%s\","
+ "\"code\":\"%s\","
+ "\"level\":\"warning\","
+ "\"message\":\"%s\","
+ "\"path\":\"%s\","
+ "\"line\":%d,"
+ "\"column\":%d"
+ "}",
escapeJson(SOURCE),
escapeJson(ruleCode),
escapeJson(lint.getDetail()),
escapeJson(path),
lint.getLineStart(),
1);
}

/**
* Escapes special characters in a string for JSON compatibility.
*/
private static String escapeJson(String str) {
if (str == null) {
return "";
}
return str
.replace("\\", "\\\\")
.replace("\"", "\\\"")
.replace("\n", "\\n")
.replace("\r", "\\r")
.replace("\t", "\\t")
.replace("\b", "\\b")
.replace("\f", "\\f");
}
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
@ParametersAreNonnullByDefault
@ReturnValuesAreNonnullByDefault
package com.diffplug.spotless.extra.middleware;

import javax.annotation.ParametersAreNonnullByDefault;

import com.diffplug.spotless.annotations.ReturnValuesAreNonnullByDefault;
Original file line number Diff line number Diff line change
@@ -0,0 +1,112 @@
/*
* Copyright 2022-2025 DiffPlug
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.diffplug.spotless.extra.middleware;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.junit.jupiter.api.Test;

import com.diffplug.selfie.Selfie;
import com.diffplug.spotless.FormatterStep;
import com.diffplug.spotless.Lint;

public class ReviewDogGeneratorTest {

@Test
public void diffSingleLine() {
String result = ReviewDogGenerator.rdjsonlDiff("test.txt", "dirty", "clean");
Selfie.expectSelfie(result).toBe("{\"message\":{\"path\":\"test.txt\",\"message\":\"File requires formatting\",\"diff\":\"--- a/test.txt\\n+++ b/test.txt\\n@@ -1,1 +1,1 @@\\n-dirty\\n+clean\\n\"}}");
}

@Test
public void diffNoChange() {
String result = ReviewDogGenerator.rdjsonlDiff("test.txt", "same", "same");
Selfie.expectSelfie(result).toBe("");
}

@Test
public void diffMultipleLines() {
String actual = "Line 1\nLine 2\nDirty line\nLine 4";
String formatted = "Line 1\nLine 2\nClean line\nLine 4";

String result = ReviewDogGenerator.rdjsonlDiff("src/main.java", actual, formatted);
Selfie.expectSelfie(result).toBe("{\"message\":{\"path\":\"src/main.java\",\"message\":\"File requires formatting\",\"diff\":\"--- a/src/main.java\\n+++ b/src/main.java\\n@@ -1,4 +1,4 @@\\n-Line 1\\n-Line 2\\n-Dirty line\\n-Line 4\\n+Line 1\\n+Line 2\\n+Clean line\\n+Line 4\\n\"}}");
}

@Test
public void lintsEmpty() {
List<FormatterStep> steps = new ArrayList<>();
List<List<Lint>> lintsPerStep = new ArrayList<>();

String result = ReviewDogGenerator.rdjsonlLintsFromSteps("test.txt", steps, lintsPerStep);
Selfie.expectSelfie(result).toBe("");
}

@Test
public void lintsSingleIssue() {
FormatterStep step = FormatterStep.create(
"testStep",
"formatter-state",
state -> rawUnix -> rawUnix);
List<FormatterStep> steps = Collections.singletonList(step);

Lint lint = Lint.atLine(1, "TEST001", "Test lint message");
List<List<Lint>> lintsPerStep = Collections.singletonList(Collections.singletonList(lint));

String result = ReviewDogGenerator.rdjsonlLintsFromSteps("src/main.java", steps, lintsPerStep);
Selfie.expectSelfie(result).toBe("{\"source\":\"spotless\",\"code\":\"testStep\",\"level\":\"warning\",\"message\":\"Test lint message\",\"path\":\"src/main.java\",\"line\":1,\"column\":1}");
}

@Test
public void lintsMultipleIssues() {
FormatterStep step1 = new FormatterStep() {
@Override
public String getName() {
return "step1";
}

@Override
public String format(String rawUnix, File file) {
return rawUnix;
}

@Override
public void close() {}
};

FormatterStep step2 = FormatterStep.create(
"step2",
"formatter-state",
state -> rawUnix -> rawUnix);

List<FormatterStep> steps = Arrays.asList(step1, step2);

Lint lint1 = Lint.atLine(1, "RULE1", "First issue");
Lint lint2 = Lint.atLine(5, "RULE2", "Second issue");

List<List<Lint>> lintsPerStep = Arrays.asList(
Collections.singletonList(lint1),
Collections.singletonList(lint2));

String result = ReviewDogGenerator.rdjsonlLintsFromSteps("src/main.java", steps, lintsPerStep);
Selfie.expectSelfie(result).toBe("{\"source\":\"spotless\",\"code\":\"step1\",\"level\":\"warning\",\"message\":\"First issue\",\"path\":\"src/main.java\",\"line\":1,\"column\":1}",
"{\"source\":\"spotless\",\"code\":\"step2\",\"level\":\"warning\",\"message\":\"Second issue\",\"path\":\"src/main.java\",\"line\":5,\"column\":1}");
}
}
2 changes: 1 addition & 1 deletion lib/src/main/java/com/diffplug/spotless/LintState.java
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright 2024 DiffPlug
* Copyright 2024-2025 DiffPlug
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand Down
2 changes: 2 additions & 0 deletions plugin-gradle/CHANGES.md
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
### Changed
* Bump default `eclipse` version to latest `4.34` -> `4.35`. ([#2458](https://github.com/diffplug/spotless/pull/2458))
* Bump default `greclipse` version to latest `4.32` -> `4.35`. ([#2458](https://github.com/diffplug/spotless/pull/2458))
### Added
* pgp key had expired, this and future releases will be signed by new key ([details](https://github.com/diffplug/spotless/discussions/2464))
* Implement conversion of diff content to ReviewDog format ([#2478](https://github.com/diffplug/spotless/pull/2478))

## [7.0.3] - 2025-04-07
### Changed
Expand Down
42 changes: 42 additions & 0 deletions plugin-gradle/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,7 @@ Spotless supports all of Gradle's built-in performance features (incremental bui
- [Multiple (or custom) language-specific blocks](#multiple-or-custom-language-specific-blocks)
- [Inception (languages within languages within...)](#inception-languages-within-languages-within)
- [Disabling warnings and error messages](#disabling-warnings-and-error-messages)
- [Reviewdog integration for CI](#reviewdog-integration-for-ci)
- [Dependency resolution modes](#dependency-resolution-modes)
- [How do I preview what `spotlessApply` will do?](#how-do-i-preview-what-spotlessapply-will-do)
- [Example configurations (from real-world projects)](#example-configurations-from-real-world-projects)
Expand Down Expand Up @@ -1768,6 +1769,47 @@ spotless {
ignoreErrorForPath('path/to/file.java') // ignore errors by all steps on this specific file
```

<a name="reviewdog"></a>

## Reviewdog integration for CI

**CURRENTLY IN BETA** – bug reports are welcome! This is a challenging feature to test comprehensively, so we anticipate needing a few releases to get everything right.
Spotless can generate reports compatible with [Reviewdog](https://github.com/reviewdog/reviewdog), a tool that automates code review tasks by posting formatting issues as comments on pull requests.

### Enabling Reviewdog integration

To enable Reviewdog output:

```gradle
spotless {
reviewdogOutput file("${buildDir}/spotless-reviewdog.json")
}
```

### Automatic report generation on check failure

To generate reports when `spotlessCheck` fails:

```gradle
tasks.named('spotlessCheck').configure {
ignoreFailures = true
doLast {
if (state.failure != null) {
logger.lifecycle("Spotless check failed – generating Reviewdog report")

if (project.hasProperty('reviewdogOutput')) {
// Insert logic here to generate reviewdogOutput
// Example: file(project.reviewdogOutput).text = spotlessCheckOutput
}
}
}
}

```

For Reviewdog setup instructions, visit: https://github.com/reviewdog/reviewdog#installation


<a name="dependency-resolution-modes"></a>
## Dependency resolution modes

Expand Down
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