gitector · michalkozminski · Sep 19, 2020 · Sep 13, 2020 · Sep 13, 2020
diff --git a/reader/converter.go b/reader/converter.go
@@ -4,7 +4,7 @@ import (
 	"strings"
 )
 
-func StringToModel(message string, signature Signature, filesCount int) GitCommit {
+func StringToModel(message string, signature Signature, filesCount int, isMerge bool) GitCommit {
 	var res = strings.SplitN(message, "\n", 2)
 	if len(res) == 1 {
 		return GitCommit{Title: message, Description: "", Signature: signature, RawMessage: message}

diff --git a/reader/converter_test.go b/reader/converter_test.go
@@ -21,7 +21,7 @@ and continues
 
 and continues
 `
-	commit := StringToModel(message, Signature{}, 3)
+	commit := StringToModel(message, Signature{}, 3, false)
 	assert.Equal(t, len(strings.Split(commit.Title, "\n")), 1)
 	assert.Equal(t, len(strings.Split(commit.Description, "\n")), 13)
 	assert.Equal(t, commit.FilesCount, 3)
@@ -36,7 +36,7 @@ body continues
 and continues
 and continues
 `
-	commit := StringToModel(message, Signature{}, 0)
+	commit := StringToModel(message, Signature{}, 0, false)
 	assert.Equal(t, len(strings.Split(commit.Title, "\n")), 1)
 	assert.Equal(t, len(strings.Split(commit.Description, "\n")), 7)
 }

diff --git a/reader/direct_input_reader.go b/reader/direct_input_reader.go
@@ -23,5 +23,5 @@ func ReadDirectInput(directory string) []GitCommit {
 	rawAuthor := string(out)
 	commit, _ := ioutil.ReadFile(".git/COMMIT_EDITMSG")
 	rawCommit := string(commit)
-	return []GitCommit{StringToModel(rawCommit, GitVarToSignature(rawAuthor), changedFiles)}
+	return []GitCommit{StringToModel(rawCommit, GitVarToSignature(rawAuthor), changedFiles, false)}
 }
diff --git a/reader/directory_reader.go b/reader/directory_reader.go
@@ -18,7 +18,7 @@ func ReadGitCommitsFromDirectory(directory string, scope string) []GitCommit {
 
 		var models []GitCommit
 		iterateOverCommon(r, getHashFromBranchName(r, a), getHashFromBranchName(r, b), func(c *object.Commit) error {
-			models = append(models, StringToModel(c.Message, Signature{Email: c.Author.Email, Name: c.Author.Name}, countFilesInCommit(c)))
+			models = append(models, StringToModel(c.Message, Signature{Email: c.Author.Email, Name: c.Author.Name}, countFilesInCommit(c), isMergeCommit(c)))
 			return nil
 		})
 		return models
@@ -90,3 +90,7 @@ func countFilesInCommit(commit *object.Commit) int {
 
 	return count
 }
+
+func isMergeCommit(commit *object.Commit) bool {
+	return len(commit.ParentHashes) > 1
+}
diff --git a/reader/reader.go b/reader/reader.go
@@ -16,6 +16,7 @@ type GitCommit struct {
 	RawMessage  string
 	Signature   Signature
 	FilesCount  int
+	IsMerge     bool
 }
 
 type Signature struct {

diff --git a/rules/config.go b/rules/config.go
@@ -16,6 +16,7 @@ type ProjectConfig struct {
 	noTrailingPunctuationInTitle bool
 	maxFiles                     int
 	startsWithVerb               bool
+	forbidMerge                  bool
 }
 
 var k = koanf.New(".")
@@ -44,6 +45,7 @@ func ReadConfig(directory string) ProjectConfig {
 		noTrailingPunctuationInTitle: k.Bool("no_trailing_punctuation_in_title"),
 		maxFiles:                     k.Int("max_files"),
 		startsWithVerb:               k.Bool("starts_with_verb"),
+		forbidMerge:                  k.Bool("forbid_merge"),
 	}
 
 	return config

diff --git a/rules/forbid_merges.go b/rules/forbid_merges.go
@@ -0,0 +1,18 @@
+package rules
+
+import "gitlab.com/tbacompany/gitector/reader"
+
+type ContainsMergeCommit struct{}
+
+func ForbidMerges(isMerge bool, isEnabled bool) bool {
+	return isMerge && isEnabled
+}
+
+func ContainsMergeCommitError(commit reader.GitCommit) GitError {
+	return GitError{
+		ErrorType:   ContainsMergeCommit{},
+		Title:       "Commit is a merge commit",
+		Description: "Merge commits are disabled please use rebase instead",
+		Commit:      commit,
+	}
+}
diff --git a/rules/rules.go b/rules/rules.go
@@ -62,5 +62,9 @@ func singleCommit(description reader.GitCommit, config ProjectConfig) []GitError
 		errors = append(errors, StartsWithBaseVerbError(description.Title, description))
 	}
 
+	if ForbidMerges(description.IsMerge, config.forbidMerge) {
+		errors = append(errors, ContainsMergeCommitError(description))
+	}
+
 	return errors
 }
diff --git a/utils/init.go b/utils/init.go
@@ -12,7 +12,8 @@ var defaultConfig = []byte(`
   "ticket_regexp": "",
   "no_trailing_punctuation_in_title": true,
   "max_files": 0,
-  "starts_with_verb": true
+  "starts_with_verb": true,
+  "forbid_merge": false
 
 }
 `)