feat(changelog): prepend a changelog to a file as default, use --overwrite to overwrite the whole file

BREAKING CHANGE: changelog command will now prepend changelogs to the changelog-file

cmd/go-semantic-release/commands/changelog.go

@@ -8,6 +8,7 @@ import (
 
 func init() {
 	changelogCmd.Flags().Bool("checks", false, "Check for missing values and envs")
+	changelogCmd.Flags().Bool("overwrite", false, "Overwrite the content of the changelog. Default is to prepend the new changelog to the existing file.")
 	changelogCmd.Flags().StringP("out", "o", "CHANGELOG.md", "Name of the file")
 	rootCmd.AddCommand(changelogCmd)
 }
@@ -31,6 +32,11 @@ var changelogCmd = &cobra.Command{
 			return err
 		}
 
+		overwrite, err := cmd.Flags().GetBool("overwrite")
+		if err != nil {
+			return err
+		}
+
 		file, err := cmd.Flags().GetString("out")
 		if err != nil {
 			return err
@@ -61,7 +67,6 @@ var changelogCmd = &cobra.Command{
 		if err != nil {
 			return err
 		}
-
-		return s.WriteChangeLog(generatedChangelog.Content, file)
+		return s.WriteChangeLog(generatedChangelog.Content, file, overwrite)
 	},
 }

pkg/semanticrelease/semantic-release.go

@@ -2,10 +2,11 @@ package semanticrelease
 
 import (
 	"fmt"
-	"github.com/Nightapes/go-semantic-release/internal/integrations"
-	"io/ioutil"
+	"os"
 	"time"
 
+	"github.com/Nightapes/go-semantic-release/internal/integrations"
+
 	"github.com/Masterminds/semver"
 	log "github.com/sirupsen/logrus"
 
@@ -194,8 +195,21 @@ func (s *SemanticRelease) GetChangelog(releaseVersion *shared.ReleaseVersion) (*
 }
 
 // WriteChangeLog writes changelog content to the given file
-func (s *SemanticRelease) WriteChangeLog(changelogContent, file string) error {
-	return ioutil.WriteFile(file, []byte(changelogContent), 0644)
+func (s *SemanticRelease) WriteChangeLog(changelogContent, file string, overwrite bool) error {
+	newContent := make([]byte, 0)
+	newContent = append(newContent, []byte(changelogContent)...)
+
+	// only prepend the new changelog content if the the given file already exists
+	_, err := os.Stat(file)
+	if !overwrite && err == nil {
+		content, err := os.ReadFile(file)
+		if err != nil {
+			return err
+		}
+		newContent = append(newContent, []byte("\n---\n\n")...)
+		newContent = append(newContent, content...)
+	}
+	return os.WriteFile(file, newContent, 0644)
 }
 
 // Release publish release to provider