Determine previous release commit for always-use-branch release Trains.

Closes #108

src/main/java/org/springframework/data/release/git/GitOperations.java

@@ -575,6 +575,18 @@ public class GitOperations {
 		if (iteration.contains(project)) {
 
 			Iteration it = iteration.getIteration();
+
+			if (iteration.getTrain().isAlwaysUseBranch()) {
+
+				Branch from = Branch.from(iteration.getModule(project));
+				String message = expandSummary("Release version %s", iteration.getModule(project), iteration);
+
+				RevCommit releaseCommit = findCommit(git, from, message);
+				if (releaseCommit != null) {
+					return releaseCommit;
+				}
+			}
+
 			Optional<Tag> fromTag = tags.filter(iteration.getTrain()).findTag(it);
 
 			if (!fromTag.isPresent()) {
@@ -583,13 +595,11 @@ public class GitOperations {
 				if (supportStatus == SupportStatus.COMMERCIAL && (it.isServiceIteration() || it.isGAIteration())) {
 
 					Branch from = Branch.from(iteration.getModule(project));
-					Iterable<RevCommit> commits = git.log().add(repo.resolve(from.toString())).call();
+					String message = "Seed " + from + " branch";
 
-					Optional<RevCommit> first = Streamable.of(commits).stream()
-							.filter(rev -> rev.getFullMessage().contains("Seed " + from + " branch")).findFirst();
-
-					if (first.isPresent()) {
-						return first.get();
+					RevCommit first = findCommit(git, from, message);
+					if (first != null) {
+						return first;
 					}
 				}
 
@@ -606,6 +616,16 @@ public class GitOperations {
 		return repo.resolve(getFirstCommit(repo));
 	}
 
+	private static RevCommit findCommit(Git git, Branch branch, String message) throws GitAPIException, IOException {
+
+		Iterable<RevCommit> commits = git.log().add(git.getRepository().resolve(branch.toString())).call();
+
+		Optional<RevCommit> first = Streamable.of(commits).stream().filter(rev -> rev.getFullMessage().contains(message))
+				.findFirst();
+
+		return first.orElse(null);
+	}
+
 	protected ObjectId resolveUpperBoundary(ModuleIteration iteration, VersionTags tags, Repository repo)
 			throws IOException {
 
@@ -1133,7 +1153,7 @@ public class GitOperations {
 	private Optional<Tag> findTagFor(SupportedProject project, ArtifactVersion version) {
 
 		return getTags(project).stream()//
-				.filter(tag -> tag.toArtifactVersion().map(it -> it.equals(version)).orElse(false))//
+				.filter(tag -> tag.getArtifactVersion().map(it -> it.equals(version)).orElse(false))//
 				.findFirst();
 	}
 

src/main/java/org/springframework/data/release/git/Tag.java

@@ -15,15 +15,14 @@
  */
 package org.springframework.data.release.git;
 
-import lombok.AccessLevel;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
-import lombok.RequiredArgsConstructor;
 
 import java.time.LocalDateTime;
 import java.util.Optional;
 
 import org.springframework.data.release.model.ArtifactVersion;
+import org.springframework.lang.Nullable;
 
 /**
  * Value object to represent an SCM tag.
@@ -32,13 +31,35 @@ import org.springframework.data.release.model.ArtifactVersion;
  * @author Mark Paluch
  */
 @EqualsAndHashCode
-@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
-@Getter
 public class Tag implements Comparable<Tag> {
 
+	@Getter
 	private final String name;
+	@Getter
 	private final LocalDateTime creationDate;
 
+	private final @Nullable ArtifactVersion artifactVersion;
+
+	private Tag(String name, LocalDateTime creationDate, @Nullable ArtifactVersion artifactVersion) {
+		this.name = name;
+		this.creationDate = creationDate;
+		this.artifactVersion = artifactVersion;
+	}
+
+	private Tag(String name, LocalDateTime creationDate) {
+		this.name = name;
+		this.creationDate = creationDate;
+
+		ArtifactVersion artifactVersion;
+		try {
+			artifactVersion = ArtifactVersion.of(getVersionSource());
+		} catch (Exception e) {
+			artifactVersion = null;
+		}
+
+		this.artifactVersion = artifactVersion;
+	}
+
 	public static Tag of(String source) {
 		return of(source, LocalDateTime.now());
 	}
@@ -61,20 +82,20 @@ public class Tag implements Comparable<Tag> {
 	}
 
 	public boolean isVersionTag() {
-		return toArtifactVersion().isPresent();
+		return getArtifactVersion().isPresent();
 	}
 
-	public Optional<ArtifactVersion> toArtifactVersion() {
-
-		try {
-			return Optional.of(getRequiredArtifactVersion());
-		} catch (IllegalArgumentException o_O) {
-			return Optional.empty();
-		}
+	public Optional<ArtifactVersion> getArtifactVersion() {
+		return Optional.ofNullable(artifactVersion);
 	}
 
 	public ArtifactVersion getRequiredArtifactVersion() {
-		return ArtifactVersion.of(getVersionSource());
+
+		if (artifactVersion == null) {
+			throw new IllegalStateException(String.format("Artifact version not set for tag '%s'", name));
+		}
+
+		return this.artifactVersion;
 	}
 
 	/**
@@ -84,7 +105,8 @@ public class Tag implements Comparable<Tag> {
 	 * @return
 	 */
 	public Tag createNew(ArtifactVersion version) {
-		return new Tag(name.startsWith("v") ? "v".concat(version.toString()) : version.toString(), LocalDateTime.now());
+		return new Tag(name.startsWith("v") ? "v".concat(version.toString()) : version.toString(), LocalDateTime.now(),
+				artifactVersion);
 	}
 
 	/*
@@ -105,7 +127,7 @@ public class Tag implements Comparable<Tag> {
 
 		// Prefer artifact versions but fall back to name comparison
 
-		return toArtifactVersion().map(left -> that.toArtifactVersion().map(right -> left.compareTo(right)).//
+		return getArtifactVersion().map(left -> that.getArtifactVersion().map(right -> left.compareTo(right)).//
 				orElse(name.compareTo(that.name))).orElse(name.compareTo(that.name));
 	}
 }

src/main/java/org/springframework/data/release/git/VersionTags.java

@@ -159,7 +159,7 @@ public class VersionTags implements Streamable<Tag> {
 
 		for (Tag tag : tags) {
 
-			Optional<ArtifactVersion> artifactVersion = tag.toArtifactVersion();
+			Optional<ArtifactVersion> artifactVersion = tag.getArtifactVersion();
 			if (!artifactVersion.isPresent()) {
 				continue;
 			}

src/main/java/org/springframework/data/release/projectservice/ProjectServiceOperations.java

@@ -207,7 +207,7 @@ class ProjectServiceOperations {
 				.filter(tag -> matches(tag, module.getVersion())).max(Comparator.naturalOrder()) //
 				.map(it -> {
 					MaintainedVersion maintainedVersion = MaintainedVersion.of(module.getProject(),
-							it.toArtifactVersion().get(),
+							it.getRequiredArtifactVersion(),
 							train, it.getCreationDate().toLocalDate(), it.getCreationDate().toLocalDate());
 					return Arrays.asList(maintainedVersion, maintainedVersion.nextDevelopmentVersion());
 				}) //
@@ -227,7 +227,7 @@ class ProjectServiceOperations {
 	 */
 	private static boolean matches(Tag tag, Version version) {
 
-		return tag.toArtifactVersion()//
+		return tag.getArtifactVersion()//
 				.map(it -> it.isVersionWithin(version))//
 				.orElse(false);
 	}