If we detect any missing commit signatures, add a link to the comment…

… that tells how to sign git commits. Fixes Issue# 119.

github/github.go

@@ -343,24 +343,11 @@ func EvaluatePullRequest(logger *zap.Logger, postgres db.IClaDB, evalInfo *types
 			}
 		}
 
-		message := `Thanks for the contribution. Unfortunately some of your commits don't meet our standards. All commits must be signed and have author information set.
-		
-The commits to review are:
-		
-%s`
-		commitsMessage := ""
-		for _, c := range commitsMissingAuthor {
-			commitsMessage += fmt.Sprintf(`- <a href="%s">%s</a> - missing author :cop:
-`, *c.HTMLURL, *c.SHA)
-		}
-		for _, c := range commitsMissingVerification {
-			commitsMessage += fmt.Sprintf(`- <a href="%s">%s</a> - unsigned commit :key:
-`, *c.HTMLURL, *c.SHA)
-		}
-		logger.Debug("Adding Comment to Issue", zap.Int("Issue #", int(evalInfo.PRNumber)), zap.String("Comment", fmt.Sprintf(message, commitsMessage)))
+		commentMessage := buildCommentMessage(commitsMissingAuthor, commitsMissingVerification)
+		logger.Debug("Adding Comment to Issue", zap.Int("Issue #", int(evalInfo.PRNumber)), zap.String("Comment", commentMessage))
 		_, err = addCommentToIssueIfNotExists(
 			client.Issues, evalInfo.RepoOwner, evalInfo.RepoName, int(evalInfo.PRNumber),
-			fmt.Sprintf(message, commitsMessage))
+			commentMessage)
 		if err != nil {
 			return err
 		}
@@ -444,6 +431,36 @@ The commits to review are:
 	return nil
 }
 
+const buildCommentPrefix = `Thanks for the contribution. Unfortunately some of your commits don't meet our standards. All commits must be signed and have author information set.
+		
+The commits to review are:
+		
+%s%s`
+
+const buildCommentSuffixSignedCommits = `
+See [Signed Commits](https://contribute.sonatype.com/docs/contributing/submitting/#signed-commits).
+`
+
+func buildCommentMessage(commitsMissingAuthor []github.RepositoryCommit, commitsMissingVerification []github.RepositoryCommit) string {
+
+	commitsMessage := ""
+	for _, c := range commitsMissingAuthor {
+		commitsMessage += fmt.Sprintf(`- <a href="%s">%s</a> - missing author :cop:
+`, *c.HTMLURL, *c.SHA)
+	}
+	for _, c := range commitsMissingVerification {
+		commitsMessage += fmt.Sprintf(`- <a href="%s">%s</a> - unsigned commit :key:
+`, *c.HTMLURL, *c.SHA)
+	}
+
+	buildCommentSuffix := ""
+	if len(commitsMissingVerification) > 0 {
+		buildCommentSuffix = buildCommentSuffixSignedCommits
+	}
+	commentMessage := fmt.Sprintf(buildCommentPrefix, commitsMessage, buildCommentSuffix)
+	return commentMessage
+}
+
 func createRepoStatus(repositoryService RepositoriesService, owner, repo, sha, state, description, botName string) error {
 	_, _, err := repositoryService.CreateStatus(context.Background(), owner, repo, sha, &github.RepoStatus{State: &state, Description: &description, Context: &botName})
 	if err != nil {

github/github_test.go

@@ -500,6 +500,40 @@ func TestHandlePullRequestMissingPemFile(t *testing.T) {
 	assert.EqualError(t, err, "could not read private key: open the-cla.pem: no such file or directory")
 }
 
+func TestBuildCommentMessageEmptyArgs(t *testing.T) {
+	commentMessage := buildCommentMessage([]github.RepositoryCommit{}, []github.RepositoryCommit{})
+	assert.Equal(t, fmt.Sprintf(buildCommentPrefix, "", ""), commentMessage)
+}
+
+func TestBuildCommentMessageMissingAuthor(t *testing.T) {
+	myUrl := "https://github.com"
+	mySha := "sha"
+	commentMessage := buildCommentMessage([]github.RepositoryCommit{
+		{HTMLURL: &myUrl, SHA: &mySha},
+	}, []github.RepositoryCommit{})
+	assert.Equal(t, fmt.Sprintf(buildCommentPrefix, "- <a href=\"https://github.com\">sha</a> - missing author :cop:\n", ""), commentMessage)
+}
+
+func TestBuildCommentMessageMissingVerification(t *testing.T) {
+	myUrl := "https://github.com"
+	mySha := "sha"
+	commentMessage := buildCommentMessage([]github.RepositoryCommit{}, []github.RepositoryCommit{
+		{HTMLURL: &myUrl, SHA: &mySha},
+	})
+	assert.Equal(t, fmt.Sprintf(buildCommentPrefix, "- <a href=\"https://github.com\">sha</a> - unsigned commit :key:\n", buildCommentSuffixSignedCommits), commentMessage)
+}
+
+func TestBuildCommentMessageMissingAuthorAndVerification(t *testing.T) {
+	myUrl := "https://github.com"
+	mySha := "sha"
+	commentMessage := buildCommentMessage([]github.RepositoryCommit{
+		{HTMLURL: &myUrl, SHA: &mySha},
+	}, []github.RepositoryCommit{
+		{HTMLURL: &myUrl, SHA: &mySha},
+	})
+	assert.Equal(t, fmt.Sprintf(buildCommentPrefix, "- <a href=\"https://github.com\">sha</a> - missing author :cop:\n- <a href=\"https://github.com\">sha</a> - unsigned commit :key:\n", buildCommentSuffixSignedCommits), commentMessage)
+}
+
 func TestHandlePullRequestListCommitsNoAuthor(t *testing.T) {
 	origGHAppIDEnvVar := os.Getenv(EnvGhAppId)
 	defer func() {
@@ -561,6 +595,8 @@ The commits to review are:
 		
 - <a href="https://github.com">johnSHA</a> - missing author :cop:
 - <a href="https://github.com">johnSHA</a> - unsigned commit :key:
+
+See [Signed Commits](https://contribute.sonatype.com/docs/contributing/submitting/#signed-commits).
 `,
 						)},
 					}, // comment