From 44a820e64113608948d477e8dbfdb4d75581e004 Mon Sep 17 00:00:00 2001
From: JFronny <git@akbvopenfl1.hopto.org>
Date: Mon, 25 Mar 2024 14:04:11 +0100
Subject: [PATCH] feat: rewrite commit parsing to support revert/reapply and
 merge commits

---
 .../io/gitlab/jfronny/scripts/CommitType.kt   | 53 +++++++++++++------
 .../io/gitlab/jfronny/scripts/JGitExt.kt      |  6 ++-
 .../src/main/kotlin/jf.autoversion.gradle.kts |  1 +
 3 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/CommitType.kt b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/CommitType.kt
index 1bafa8d..147d4f6 100644
--- a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/CommitType.kt
+++ b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/CommitType.kt
@@ -4,25 +4,48 @@ enum class CommitType {
     FIX, FEAT, BREAKING;
 
     companion object {
-        private val pattern: Regex = Regex("([a-zA-Z ]+)(?:\\([a-zA-Z0-9 -]+\\))?(!)?: .+", RegexOption.DOT_MATCHES_ALL)
+        private val conventionalPattern = Regex("^(\\w+)(\\(([\\w\\-.,\\s:]+)\\)?)?(!?)[\\s?]*:(.+)")
+        private val footerPattern = Regex("^(BREAKING[ -]CHANGE|[^ ]+)(((: )|( #))(.+))")
 
         fun from(commitMessage: String, warn: (String) -> Unit): CommitType {
-            val match = pattern.matchEntire(commitMessage)
-            if (match != null) {
-                val m = match.groupValues
-                if (m[2] == "!") return BREAKING
-                return when (m[1].lowercase()) {
-                    "fix", "build", "chore", "ci", "docs", "style", "refactor", "perf", "test" -> FIX
-                    "feat" -> FEAT
-                    "breaking change", "breaking" -> BREAKING
-                    else -> {
-                        warn("Unrecognized commit type: ${m[1]}, guessing FEAT")
-                        FEAT
-                    }
+            val lines = commitMessage.trim().split("\\r?\\n")
+            val headerMatch = conventionalPattern.matchEntire(extractHeader(lines[0]))
+            if (headerMatch == null) {
+                warn("Could not parse commit, guessing type is FEAT: $commitMessage")
+                return FEAT
+            }
+            if (headerMatch.groupValues[3] == "!") return BREAKING
+            for (s in lines.drop(1).filterNot { it.isBlank() }) {
+                val footerMatch = footerPattern.matchEntire(s)
+                if (footerMatch != null) {
+                    val type = footerMatch.groupValues[1].lowercase()
+                    if (type == "breaking change" || type == "breaking-change") return BREAKING
                 }
             }
-            warn("Could not parse commit, guessing type is FEAT: $commitMessage")
-            return FEAT
+            return when (headerMatch.groupValues[1].lowercase()) {
+                "fix", "build", "chore", "ci", "docs", "style", "refactor", "perf", "test" -> FIX
+                "feat" -> FEAT
+                "breaking change", "breaking" -> BREAKING
+                else -> {
+                    warn("Unrecognized commit type: ${headerMatch.groupValues[1]}, guessing FEAT")
+                    FEAT
+                }
+            }
+        }
+
+        private val revertPattern = Regex("^Revert \"(.+)\"", RegexOption.IGNORE_CASE)
+        private val reapplyPattern = Regex("^Reapply \"(.+)\"", RegexOption.IGNORE_CASE)
+
+        private tailrec fun extractHeader(headerLine: String): String {
+            if (headerLine.startsWith("Revert ")) {
+                val revertMatch = revertPattern.matchEntire(headerLine)
+                if (revertMatch != null) return extractHeader(revertMatch.groupValues[1])
+            }
+            if (headerLine.startsWith("Reapply ")) {
+                val reapplyMatch = reapplyPattern.matchEntire(headerLine)
+                if (reapplyMatch != null) return extractHeader(reapplyMatch.groupValues[1])
+            }
+            return headerLine
         }
     }
 }
\ No newline at end of file
diff --git a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
index 96518ab..dc25bb5 100644
--- a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
+++ b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
@@ -76,7 +76,7 @@ fun RevCommit.resolve(repo: Repository): Commit = Commit(
     ),
     fullMessage,
     shortMessage,
-    parents.map { ObjectId.toString(it) }
+    parents?.map { ObjectId.toString(it) } ?: emptyList()
 )
 
 private val String?.nullable get() = if (this == null || this == "") null else this
@@ -86,4 +86,6 @@ data class Tag(val id: ObjectId, val original: RevTag?, val fullName: String, va
     val peeledId: ObjectId get() = commit.original.id
 }
 data class Commit(val original: RevCommit, val id: ObjectId, val abbreviatedId: String?, val committer: Person, val author: Person, val dateTime: ZonedDateTime, val fullMessage: String, val shortMessage: String, val parentIds: List<String>)
-data class Person(val original: PersonIdent, val name: String, val emailAddress: String)
\ No newline at end of file
+data class Person(val original: PersonIdent, val name: String, val emailAddress: String)
+
+private val Commit.isMerge get() = parentIds.size > 1
\ No newline at end of file
diff --git a/convention/src/main/kotlin/jf.autoversion.gradle.kts b/convention/src/main/kotlin/jf.autoversion.gradle.kts
index 3037377..127e00b 100644
--- a/convention/src/main/kotlin/jf.autoversion.gradle.kts
+++ b/convention/src/main/kotlin/jf.autoversion.gradle.kts
@@ -30,6 +30,7 @@ if (File(projectDir, ".git").exists()) {
                 val log = git.log(tags[0].peeledId, git.repository.resolve("HEAD")).reversed()
                 changelog += log.joinToString("\n") { "- ${it.shortMessage}" }
                 val type = log.stream()
+                    .filter { !it.isMerge }
                     .map { it.fullMessage }
                     .map { msg -> CommitType.from(msg) { logger.warn(it) } }
                     .max { o1, o2 -> o1.compareTo(o2) }