Merge pull request #1461 from lutovich/improve-maven-plugin-fingerprint

Reduce spurious invalidations of the up-to-date index in Maven plugin
diffplug · Jan 8, 2023 · c50503e · c50503e
2 parents 1b2c449 + 016eecf
commit c50503e
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diff --git a/plugin-maven/CHANGES.md b/plugin-maven/CHANGES.md
@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Reduce spurious invalidations of the up-to-date index file ([#1461](https://github.com/diffplug/spotless/pull/1461))
 
 ## [2.29.0] - 2023-01-02
 ### Added

diff --git a/plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/FileIndex.java b/plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/FileIndex.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -76,7 +76,7 @@ static FileIndex read(FileIndexConfig config, Log log) {
 			PluginFingerprint computedFingerprint = config.getPluginFingerprint();
 			PluginFingerprint storedFingerprint = PluginFingerprint.from(firstLine);
 			if (!computedFingerprint.equals(storedFingerprint)) {
-				log.info("Fingerprint mismatch in the index file. Fallback to an empty index");
+				log.info("Index file corresponds to a different configuration of the plugin. Either the plugin version or its configuration has changed. Fallback to an empty index");
 				return emptyIndexFallback(config);
 			} else {
 				Content content = readIndexContent(reader, config.getProjectDir(), log);

diff --git a/plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/PluginFingerprint.java b/plugin-maven/src/main/java/com/diffplug/spotless/maven/incremental/PluginFingerprint.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021-2022 DiffPlug
+ * Copyright 2021-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,17 +17,21 @@
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
-import java.util.ArrayList;
 import java.util.Base64;
-import java.util.List;
 import java.util.Objects;
 
-import org.apache.maven.model.Dependency;
 import org.apache.maven.model.Plugin;
 import org.apache.maven.project.MavenProject;
 
 import com.diffplug.spotless.Formatter;
 
+/**
+ * Represents a particular Spotless Maven plugin setup using a Base64-encoded serialized form of:
+ * <ol>
+ *    <li>Plugin version as configured in the POM</li>
+ *    <li>Formatter instances created according to the POM configuration</li>
+ * </ol>
+ */
 class PluginFingerprint {
 
 	private static final String SPOTLESS_PLUGIN_KEY = "com.diffplug.spotless:spotless-maven-plugin";
@@ -83,22 +87,15 @@ public String toString() {
 	}
 
 	private static byte[] digest(Plugin plugin, Iterable<Formatter> formatters) {
-		// dependencies can be an unserializable org.apache.maven.model.merge.ModelMerger$MergingList
-		// replace it with a serializable ArrayList
-		List<Dependency> dependencies = plugin.getDependencies();
-		plugin.setDependencies(new ArrayList<>(dependencies));
 		try (ObjectDigestOutputStream out = ObjectDigestOutputStream.create()) {
-			out.writeObject(plugin);
+			out.writeObject(plugin.getVersion());
 			for (Formatter formatter : formatters) {
 				out.writeObject(formatter);
 			}
 			out.flush();
 			return out.digest();
 		} catch (IOException e) {
 			throw new UncheckedIOException("Unable to serialize plugin " + plugin, e);
-		} finally {
-			// reset the original list
-			plugin.setDependencies(dependencies);
 		}
 	}
 }
diff --git a/plugin-maven/src/test/java/com/diffplug/spotless/maven/incremental/FileIndexTest.java b/plugin-maven/src/test/java/com/diffplug/spotless/maven/incremental/FileIndexTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -60,7 +60,7 @@ void readFallsBackToEmptyIndexOnFingerprintMismatch() throws Exception {
 		FileIndex index = FileIndex.read(config, log);
 
 		assertThat(index.size()).isZero();
-		verify(log).info("Fingerprint mismatch in the index file. Fallback to an empty index");
+		verify(log).info("Index file corresponds to a different configuration of the plugin. Either the plugin version or its configuration has changed. Fallback to an empty index");
 	}
 
 	@Test

diff --git a/...in-maven/src/test/java/com/diffplug/spotless/maven/incremental/PluginFingerprintTest.java b/...in-maven/src/test/java/com/diffplug/spotless/maven/incremental/PluginFingerprintTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021-2022 DiffPlug
+ * Copyright 2021-2023 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,126 +43,22 @@ class PluginFingerprintTest extends MavenIntegrationHarness {
 	private static final String VERSION_1 = "1.0.0";
 	private static final String VERSION_2 = "2.0.0";
 
-	private static final String[] EXECUTION_1 = {
-			"<execution>",
-			"  <id>check</id>",
-			"  <goals>",
-			"    <goal>check</goal>",
-			"  </goals>",
-			"</execution>"
-	};
-	private static final String[] EXECUTION_2 = {};
-
-	private static final String[] CONFIGURATION_1 = {
-			"<googleJavaFormat>",
-			"  <version>1.2</version>",
-			"</googleJavaFormat>"
-	};
-	private static final String[] CONFIGURATION_2 = {
-			"<googleJavaFormat>",
-			"  <version>1.8</version>",
-			"  <reflowLongStrings>true</reflowLongStrings>",
-			"</googleJavaFormat>"
-	};
-
-	private static final String[] DEPENDENCIES_1 = {
-			"<dependencies>",
-			"  <dependency>",
-			"    <groupId>unknown</groupId>",
-			"    <artifactId>unknown</artifactId>",
-			"    <version>1.0</version>",
-			"  </dependency>",
-			"</dependencies>"
-	};
-	private static final String[] DEPENDENCIES_2 = {
-			"<dependencies>",
-			"  <dependency>",
-			"    <groupId>unknown</groupId>",
-			"    <artifactId>unknown</artifactId>",
-			"    <version>2.0</version>",
-			"  </dependency>",
-			"</dependencies>"
-	};
-
 	private static final List<Formatter> FORMATTERS = singletonList(formatter(formatterStep("default")));
 
 	@Test
-	void sameFingerprint() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
+	void sameFingerprintWhenVersionAndFormattersAreTheSame() throws Exception {
+		MavenProject project = mavenProject(VERSION_1);
 
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
-
-		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
-		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
+		PluginFingerprint fingerprint1 = PluginFingerprint.from(project, FORMATTERS);
+		PluginFingerprint fingerprint2 = PluginFingerprint.from(project, FORMATTERS);
 
 		assertThat(fingerprint1).isEqualTo(fingerprint2);
 	}
 
 	@Test
-	void sameFingerprintWithDependencies() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
-
-		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
-		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
-
-		assertThat(fingerprint1).isEqualTo(fingerprint2);
-	}
-
-	@Test
-	void differentFingerprintForDifferentDependencies() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_1);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1, DEPENDENCIES_2);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
-
-		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
-		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
-
-		assertThat(fingerprint1).isNotEqualTo(fingerprint2);
-	}
-
-	@Test
-	void differentFingerprintForDifferentPluginVersion() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-		String xml2 = createPomXmlContent(VERSION_2, EXECUTION_1, CONFIGURATION_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
-
-		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
-		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
-
-		assertThat(fingerprint1).isNotEqualTo(fingerprint2);
-	}
-
-	@Test
-	void differentFingerprintForDifferentExecution() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_2, EXECUTION_1, CONFIGURATION_1);
-		String xml2 = createPomXmlContent(VERSION_2, EXECUTION_2, CONFIGURATION_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
-
-		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
-		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
-
-		assertThat(fingerprint1).isNotEqualTo(fingerprint2);
-	}
-
-	@Test
-	void differentFingerprintForDifferentConfiguration() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_2, CONFIGURATION_2);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_2, CONFIGURATION_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
+	void differentFingerprintForDifferentPluginVersions() throws Exception {
+		MavenProject project1 = mavenProject(VERSION_1);
+		MavenProject project2 = mavenProject(VERSION_2);
 
 		PluginFingerprint fingerprint1 = PluginFingerprint.from(project1, FORMATTERS);
 		PluginFingerprint fingerprint2 = PluginFingerprint.from(project2, FORMATTERS);
@@ -172,11 +68,8 @@ void differentFingerprintForDifferentConfiguration() throws Exception {
 
 	@Test
 	void differentFingerprintForFormattersWithDifferentSteps() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
+		MavenProject project1 = mavenProject(VERSION_1);
+		MavenProject project2 = mavenProject(VERSION_1);
 
 		FormatterStep step1 = formatterStep("step1");
 		FormatterStep step2 = formatterStep("step2");
@@ -192,11 +85,8 @@ void differentFingerprintForFormattersWithDifferentSteps() throws Exception {
 
 	@Test
 	void differentFingerprintForFormattersWithDifferentLineEndings() throws Exception {
-		String xml1 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-		String xml2 = createPomXmlContent(VERSION_1, EXECUTION_1, CONFIGURATION_1);
-
-		MavenProject project1 = mavenProject(xml1);
-		MavenProject project2 = mavenProject(xml2);
+		MavenProject project1 = mavenProject(VERSION_1);
+		MavenProject project2 = mavenProject(VERSION_1);
 
 		FormatterStep step = formatterStep("step");
 		List<Formatter> formatters1 = singletonList(formatter(LineEnding.UNIX, step));
@@ -224,7 +114,8 @@ void failsWhenProjectDoesNotContainSpotlessPlugin() {
 				.hasMessageContaining("Spotless plugin absent from the project");
 	}
 
-	private static MavenProject mavenProject(String xml) throws Exception {
+	private MavenProject mavenProject(String spotlessVersion) throws Exception {
+		String xml = createPomXmlContent(spotlessVersion, new String[0], new String[0]);
 		return new MavenProject(readPom(xml));
 	}