feat: recognize Jira issue keys in commit body

As outlined in #183 it can be useful when following the
conventional commit syntax to separate conventional
commit type in the subject from work item references
which often appear in the commit body or commit footer

this commit:

- adds a new config option 'jira.issue.key_pattern' which
  is an optional regex used to match issue keys in the
  commit subject and body

- ensures that the Jira Issue Type does not overwrite a
  Conventional Commit Type; the 'jira.issue.type_maps'
  map is only used as a backup when the Conventional
  Commit Type parsed out of the Subject header is empty

- runs the 'jira.issue.key_pattern' regex against both
  the commit Subject header and the entire commit Body

NOTE: the current code assumes that only one Jira work
      item will be bound to a single commit, and this
      appears consistent with the spirit of Conventional
      Commits. I have sometimes found it useful to write
      a Conventional Commit where one 'fix' can close
      multiple Jira work items, so a future issue/change
      might consider updating the model to support multiple
      Jira work items in a single commit message.

commit_parser.go

@@ -61,6 +61,7 @@ type commitParser struct {
 	reMention              *regexp.Regexp
 	reSignOff              *regexp.Regexp
 	reCoAuthor             *regexp.Regexp
+	reJiraKey              *regexp.Regexp
 	reJiraIssueDescription *regexp.Regexp
 }
 
@@ -71,7 +72,7 @@ func newCommitParser(logger *Logger, client gitcmd.Client, jiraClient JiraClient
 	joinedIssuePrefix := joinAndQuoteMeta(opts.IssuePrefix, "|")
 	joinedNoteKeywords := joinAndQuoteMeta(opts.NoteKeywords, "|")
 
-	return &commitParser{
+	p := commitParser{
 		logger:                 logger,
 		client:                 client,
 		jiraClient:             jiraClient,
@@ -87,6 +88,12 @@ func newCommitParser(logger *Logger, client gitcmd.Client, jiraClient JiraClient
 		reCoAuthor:             regexp.MustCompile(`Co-authored-by:\s+([\p{L}\s\-\[\]]+)\s+<([\w+\-\[\].@]+)>`),
 		reJiraIssueDescription: regexp.MustCompile(opts.JiraIssueDescriptionPattern),
 	}
+
+	if opts.JiraKeyPattern != "" {
+		p.reJiraKey = regexp.MustCompile(opts.JiraKeyPattern)
+	}
+
+	return &p
 }
 
 func (p *commitParser) Parse(rev string) ([]*Commit, error) {
@@ -153,6 +160,11 @@ func (p *commitParser) parseCommit(input string) *Commit {
 		}
 	}
 
+	// Jira
+	if commit.JiraIssueID != "" {
+		p.processJiraIssue(commit, commit.JiraIssueID)
+	}
+
 	commit.Refs = p.uniqRefs(commit.Refs)
 	commit.Mentions = p.uniqMentions(commit.Mentions)
 
@@ -206,6 +218,8 @@ func (p *commitParser) processHeader(commit *Commit, input string) {
 		assignDynamicValues(commit, opts.HeaderPatternMaps, res[0][1:])
 	}
 
+	p.populateJiraIssueIDByJiraKeyRegex(commit, input)
+
 	// Merge
 	res = p.reMerge.FindAllStringSubmatch(input, -1)
 	if len(res) > 0 {
@@ -225,11 +239,6 @@ func (p *commitParser) processHeader(commit *Commit, input string) {
 	// refs & mentions
 	commit.Refs = p.parseRefs(input)
 	commit.Mentions = p.parseMentions(input)
-
-	// Jira
-	if commit.JiraIssueID != "" {
-		p.processJiraIssue(commit, commit.JiraIssueID)
-	}
 }
 
 func (p *commitParser) extractLineMetadata(commit *Commit, line string) bool {
@@ -268,6 +277,8 @@ func (p *commitParser) processBody(commit *Commit, input string) {
 	// body
 	commit.Body = input
 
+	p.populateJiraIssueIDByJiraKeyRegex(commit, input)
+
 	// notes & refs & mentions
 	commit.Notes = []*Note{}
 	inNote := false
@@ -314,6 +325,18 @@ func (p *commitParser) processBody(commit *Commit, input string) {
 	p.trimSpaceInNotes(commit)
 }
 
+func (p *commitParser) populateJiraIssueIDByJiraKeyRegex(commit *Commit, input string) {
+	if p.reJiraKey != nil {
+		m := p.reJiraKey.FindAllString(input, -1)
+		if len(m) > 0 {
+			// NOTE: a git commit may reference multiple jira issues... here we capture only the first
+			//       a future change may resolve this by updating the commit structure to support
+			//       multiple issues
+			commit.JiraIssueID = m[0]
+		}
+	}
+}
+
 func (*commitParser) trimSpaceInNotes(commit *Commit) {
 	for _, note := range commit.Notes {
 		note.Body = strings.TrimSpace(note.Body)
@@ -432,7 +455,10 @@ func (p *commitParser) processJiraIssue(commit *Commit, issueID string) {
 		p.logger.Error(fmt.Sprintf("Failed to parse Jira story %s: %s\n", issueID, err))
 		return
 	}
-	commit.Type = p.config.Options.JiraTypeMaps[issue.Fields.Type.Name]
+	if commit.Type == "" {
+		// don't override an explicit Conventional Commit Type
+		commit.Type = p.config.Options.JiraTypeMaps[issue.Fields.Type.Name]
+	}
 	commit.JiraIssue = &JiraIssue{
 		Type:        issue.Fields.Type.Name,
 		Summary:     issue.Fields.Summary,