feat: Introduce a target version up to which migrations should be applied.

docs/modules/ROOT/pages/usage.adoc

@@ -52,6 +52,20 @@ You can spot these cases beforehand by validating your chain of migrations (see
 If you absolutely must however, you can use `withOutOfOrderAllowed` on the config object or the corresponding property in either the Spring Boot starter or the Quarkus extension.
 Setting this to true will integrate out-of-order migrations into the chain.
 
+By default, all migrations will be applied.
+However, you can configure a target version to stop at.
+The target version will always be an *inclusive* stop.
+This is especially important for repeatable migrations: If the target is repeatable and has changed since the last application, it will be applied again.
+The target version must be an exact version number as given with the file- or classname (such as `V1_2_3`, `R010`, `V100` or whatever scheme you use), specifying the description again is not necessary (See ref:concepts.adoc#concepts_naming-conventions[naming conventions]).
+Migrations does check whether the target version can be resolved and will abort if there is no such version, either in pending or applied state).
+You can use `V010?` (with a question mark) to skip this check.
+Migrations will then apply every version that is sorted below that version.
+Additionally, three special values are supported as well (These names are case-insensitive):
+
+`current`:: Designates the current version of the schema.
+`latest`:: The latest version of the schema, as defined by the migration with the highest version.
+`next`:: The next version of the schema, as defined by the first pending migration.
+
 [[usage_common_repair]]
 === Repair
 
@@ -683,12 +697,23 @@ A configurable delay that will be applied in between applying two migrations.
 - Type: `java.time.Duration`
 - Default: `false`
 
+`org.neo4j.migrations.version-sort-order`::
+How versions should be sorted. The default of `LEXICOGRAPHIC` will change to `SEMANTIC` in a future version of this library.
+
+- Type: `ac.simons.neo4j.migrations.core.MigrationsConfig#VersionSortOrder`
+- Default: `LEXICOGRAPHIC`
+
 `org.neo4j.migrations.out-of-order`::
 A flag to enable out-of-order migrations.
 
 - Type: `java.lang.Boolean`
 - Default: `false`
 
+`org.neo4j.migrations.target`::
+Configures the target version up to which migrations should be considered. This must be a valid migration version, or one of the special values `current`, `latest` or `next`.
+
+- Type: `java.lang.String`
+- Default: `null`
 
 NOTE: Migrations can be disabled by setting `org.neo4j.migrations.enabled` to `false`.
 

extensions/neo4j-migrations-annotation-processing/catalog/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-annotation-processing</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-annotation-catalog</artifactId>

extensions/neo4j-migrations-annotation-processing/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 		<relativePath>../../pom.xml</relativePath>
 	</parent>
 

extensions/neo4j-migrations-annotation-processing/processor-api/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-annotation-processing</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-annotation-processor-api</artifactId>

extensions/neo4j-migrations-annotation-processing/processor/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-annotation-processing</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-annotation-processor</artifactId>

extensions/neo4j-migrations-formats-adoc/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 		<relativePath>../../pom.xml</relativePath>
 	</parent>
 

extensions/neo4j-migrations-formats-csv/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 		<relativePath>../../pom.xml</relativePath>
 	</parent>
 

extensions/neo4j-migrations-formats-markdown/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 		<relativePath>../../pom.xml</relativePath>
 	</parent>
 

neo4j-migrations-bom/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-bom</artifactId>

neo4j-migrations-cli/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations-cli</artifactId>

neo4j-migrations-cli/src/main/java/ac/simons/neo4j/migrations/cli/MigrationsCli.java

@@ -251,6 +251,12 @@ public static void main(String... args) {
 	)
 	private boolean outOfOrder;
 
+	@Option(
+		names = {"--target"},
+		description = "Use this option to specify a valid target version up to which migrations should be considered. Can also be one of current, latest or next."
+	)
+	private String target;
+
 	@Spec
 	private CommandSpec commandSpec;
 
@@ -306,6 +312,7 @@ MigrationsConfig getConfig(boolean forceSilence) {
 			.withDelayBetweenMigrations(delayBetweenMigrations)
 			.withVersionSortOrder(versionSortOrder)
 			.withOutOfOrderAllowed(outOfOrder)
+			.withTarget(target)
 			.build();
 
 		if (!forceSilence) {

neo4j-migrations-cli/src/test/java/ac/simons/neo4j/migrations/cli/MigrationsCliTest.java

@@ -161,6 +161,26 @@ void outOfOrderShouldBeApplied() {
 		assertThat(cli.getConfig().isOutOfOrder()).isTrue();
 	}
 
+	@Test // GH-1536
+	void targetShouldBeNullByDefault() {
+
+		MigrationsCli cli = new MigrationsCli();
+		CommandLine commandLine = new CommandLine(cli);
+		commandLine.parseArgs();
+
+		assertThat(cli.getConfig().getTarget()).isNull();
+	}
+
+	@Test // GH-1536
+	void targetShouldBeApplied() {
+
+		MigrationsCli cli = new MigrationsCli();
+		CommandLine commandLine = new CommandLine(cli);
+		commandLine.parseArgs("--target=current");
+
+		assertThat(cli.getConfig().getTarget()).isEqualTo("current");
+	}
+
 	@Test
 	void shouldRequire2Connections() {
 

neo4j-migrations-core/pom.xml

@@ -22,7 +22,7 @@
 	<parent>
 		<groupId>eu.michael-simons.neo4j</groupId>
 		<artifactId>neo4j-migrations-parent</artifactId>
-		<version>2.14.2-SNAPSHOT</version>
+		<version>2.15.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>neo4j-migrations</artifactId>

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/DefaultMigrationChain.java

@@ -77,12 +77,34 @@ public Collection<Element> getElements() {
 		return this.elements.values();
 	}
 
+	@Override
+	public Optional<MigrationVersion> findTargetVersion(MigrationVersion.TargetVersion targetVersion) {
+
+		if (this.elements.isEmpty()) {
+			return Optional.empty();
+		}
+
+		return switch (targetVersion) {
+			case CURRENT -> getLastAppliedVersion();
+			case LATEST -> this.elements.keySet().stream().skip(this.elements.size() - 1L).findFirst();
+			case NEXT ->
+				this.elements.entrySet().stream().dropWhile(e -> e.getValue().getState() == MigrationState.APPLIED)
+					.map(Map.Entry::getKey)
+					.findFirst();
+		};
+	}
+
 	@Override
 	public Optional<MigrationVersion> getLastAppliedVersion() {
-		Iterator<MigrationVersion> it = this.elements.keySet().iterator();
+		Iterator<Map.Entry<MigrationVersion, Element>> it = this.elements.entrySet().iterator();
 		MigrationVersion version = null;
 		while (it.hasNext()) {
-			version = it.next();
+			var next = it.next();
+			if (next.getValue().getState() == MigrationState.APPLIED) {
+				version = next.getKey();
+			} else {
+				break;
+			}
 		}
 		return Optional.ofNullable(version);
 	}

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/IterableMigrations.java

@@ -16,8 +16,13 @@
 package ac.simons.neo4j.migrations.core;
 
 import java.time.Duration;
+import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.logging.Level;
+
+import ac.simons.neo4j.migrations.core.MigrationVersion.StopVersion;
 
 /**
  * A helper class that can be used to delay the iteration of migrations by a configurable amount of time.
@@ -31,42 +36,85 @@ final class IterableMigrations implements Iterable<Migration> {
 
 	private final List<Migration> migrations;
 
-	IterableMigrations(MigrationsConfig config, List<Migration> migrations) {
+	private final MigrationVersion optionalStop;
+
+	static IterableMigrations of(MigrationsConfig config, List<Migration> migrations) {
+		return of(config, migrations, null);
+	}
+
+	static IterableMigrations of(MigrationsConfig config, List<Migration> migrations, StopVersion stopVersion) {
+		MigrationVersion optionalStop;
+		if (stopVersion == null) {
+			optionalStop = null;
+		} else {
+			optionalStop = stopVersion.version();
+			if (!stopVersion.optional() && migrations.stream().filter(m -> m.getVersion().equals(optionalStop)).findFirst().isEmpty()) {
+				throw new MigrationsException("Target version %s is not available".formatted(optionalStop.getValue()));
+			}
+		}
+		return new IterableMigrations(config, migrations, optionalStop);
+	}
+
+	private IterableMigrations(MigrationsConfig config, List<Migration> migrations, MigrationVersion optionalStop) {
 		this.config = config;
 		this.migrations = migrations;
+		this.optionalStop = optionalStop;
 	}
 
 	@Override
 	public Iterator<Migration> iterator() {
 		var iterator = migrations.iterator();
-		return config.getOptionalDelayBetweenMigrations().map(d -> (Iterator<Migration>) new DelayingIterator(iterator, d))
-			.orElse(iterator);
+		if (optionalStop != null) {
+			Migrations.LOGGER.log(Level.INFO, "Will stop at target version {0}", optionalStop);
+		}
+		return new DelayingIterator(iterator, config.getOptionalDelayBetweenMigrations().orElse(null), config.getVersionComparator(), optionalStop);
 	}
 
 	private static final class DelayingIterator implements Iterator<Migration> {
 
 		private final Iterator<Migration> delegate;
 
-		private final Duration delay;
+		private final Duration optionalDelay;
+
+		private final Comparator<MigrationVersion> comparator;
+
+		private final MigrationVersion optionalStop;
+
+		private Migration next;
 
-		DelayingIterator(Iterator<Migration> delegate, Duration delay) {
+		DelayingIterator(Iterator<Migration> delegate, Duration optionalDelay, Comparator<MigrationVersion> comparator, MigrationVersion optionalStop) {
 			this.delegate = delegate;
-			this.delay = delay;
+			this.optionalDelay = optionalDelay;
+			this.comparator = comparator;
+			this.optionalStop = optionalStop;
 		}
 
 		@Override
 		public boolean hasNext() {
-			return delegate.hasNext();
+			var hasNext = delegate.hasNext();
+			if (hasNext) {
+				this.next = delegate.next();
+				hasNext = this.optionalStop == null || comparator.compare(next.getVersion(), optionalStop) <= 0;
+			} else {
+				this.next = null;
+			}
+			return hasNext;
 		}
 
 		@Override
-		public Migration next() {
-			try {
-				Thread.sleep(delay.toMillis());
-			} catch (InterruptedException e) {
-				Thread.currentThread().interrupt();
+		public Migration next() throws NoSuchElementException {
+			if (next == null) {
+				throw new NoSuchElementException();
+			}
+
+			if (optionalDelay != null) {
+				try {
+					Thread.sleep(optionalDelay.toMillis());
+				} catch (InterruptedException e) {
+					Thread.currentThread().interrupt();
+				}
 			}
-			return delegate.next();
+			return next;
 		}
 	}
 }

neo4j-migrations-core/src/main/java/ac/simons/neo4j/migrations/core/MigrationChain.java

@@ -21,6 +21,8 @@
 import java.util.Map;
 import java.util.Optional;
 
+import ac.simons.neo4j.migrations.core.MigrationVersion.TargetVersion;
+
 /**
  * Public information about an applied migration. All migrations (applied and pending) form a chain of transformations
  * to a database. The chain starts implicit with a baseline version. The baseline version is not contained in this chain.
@@ -114,6 +116,15 @@ default Optional<MigrationVersion> getLastAppliedVersion() {
 		return Optional.empty();
 	}
 
+	/**
+	 * Translates a target version into a concrete version
+	 *
+	 * @param targetVersion the target version to translate into a concrete version
+	 * @return the concrete version if any
+	 * @since 2.15.0
+	 */
+	Optional<MigrationVersion> findTargetVersion(TargetVersion targetVersion);
+
 	/**
 	 * A chain element describing a pending or applied migration.
 	 */