Fix Dependabot config indentation issue

remediation/dependabot/dependabotconfig.go

@@ -3,10 +3,12 @@ package dependabot
 import (
 	"bufio"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"strings"
 
 	dependabot "github.com/paulvollmer/dependabot-config-go"
-	"gopkg.in/yaml.v2"
+	"gopkg.in/yaml.v3"
 )
 
 type UpdateDependabotConfigResponse struct {
@@ -27,29 +29,79 @@ type UpdateDependabotConfigRequest struct {
 	Content    string
 }
 
+// getIndentation returns the indentation level of the first list found in a given YAML string.
+// If the YAML string is empty or invalid, or if no list is found, it returns an error.
+func getIndentation(dependabotConfig string) (int, error) {
+	// Initialize an empty YAML node
+	t := yaml.Node{}
+
+	// Unmarshal the YAML string into the node
+	err := yaml.Unmarshal([]byte(dependabotConfig), &t)
+	if err != nil {
+		return 0, fmt.Errorf("unable to parse yaml: %w", err)
+	}
+
+	// Retrieve the top node of the YAML document
+	topNode := t.Content
+	if len(topNode) == 0 {
+		return 0, errors.New("file provided is empty or invalid")
+	}
+
+	// Check for the first list and its indentation level
+	for _, n := range topNode[0].Content {
+		if n.Value == "" && n.Tag == "!!seq" {
+			// Return the column of the first list found
+			return n.Column, nil
+		}
+	}
+
+	// Return an error if no list was found
+	return 0, errors.New("no list found in yaml")
+}
+
+// UpdateDependabotConfig is used to update dependabot configuration and returns an UpdateDependabotConfigResponse.
 func UpdateDependabotConfig(dependabotConfig string) (*UpdateDependabotConfigResponse, error) {
 	var updateDependabotConfigRequest UpdateDependabotConfigRequest
-	json.Unmarshal([]byte(dependabotConfig), &updateDependabotConfigRequest)
+
+	// Handle error in json unmarshalling
+	err := json.Unmarshal([]byte(dependabotConfig), &updateDependabotConfigRequest)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unmarshal JSON from dependabotConfig: %v", err)
+	}
+
 	inputConfigFile := []byte(updateDependabotConfigRequest.Content)
 	configMetadata := dependabot.New()
-	err := configMetadata.Unmarshal(inputConfigFile)
+	err = configMetadata.Unmarshal(inputConfigFile)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to unmarshal dependabot config: %v", err)
 	}
 
+	indentation := 3
+
 	response := new(UpdateDependabotConfigResponse)
 	response.FinalOutput = updateDependabotConfigRequest.Content
 	response.OriginalInput = updateDependabotConfigRequest.Content
 	response.IsChanged = false
 
+	// Using strings.Builder for efficient string concatenation
+	var finalOutput strings.Builder
+	finalOutput.WriteString(response.FinalOutput)
+
 	if updateDependabotConfigRequest.Content == "" {
 		if len(updateDependabotConfigRequest.Ecosystems) == 0 {
 			return response, nil
 		}
-		response.FinalOutput = "version: 2\nupdates:"
+		finalOutput.WriteString("version: 2\nupdates:")
 	} else {
-		response.FinalOutput += "\n"
+		if !strings.HasSuffix(response.FinalOutput, "\n") {
+			finalOutput.WriteString("\n")
+		}
+		indentation, err = getIndentation(string(inputConfigFile))
+		if err != nil {
+			return nil, fmt.Errorf("failed to get indentation: %v", err)
+		}
 	}
+
 	for _, Update := range updateDependabotConfigRequest.Ecosystems {
 		updateAlreadyExist := false
 		for _, update := range configMetadata.Updates {
@@ -58,37 +110,56 @@ func UpdateDependabotConfig(dependabotConfig string) (*UpdateDependabotConfigRes
 				break
 			}
 		}
-		if !updateAlreadyExist {
-			item := dependabot.Update{}
-			item.PackageEcosystem = Update.PackageEcosystem
-			item.Directory = Update.Directory
 
-			schedule := dependabot.Schedule{}
-			schedule.Interval = Update.Interval
-
-			item.Schedule = schedule
-			items := []dependabot.Update{}
-			items = append(items, item)
+		if !updateAlreadyExist {
+			item := dependabot.Update{
+				PackageEcosystem: Update.PackageEcosystem,
+				Directory:        Update.Directory,
+				Schedule:         dependabot.Schedule{Interval: Update.Interval},
+			}
+			items := []dependabot.Update{item}
 			addedItem, err := yaml.Marshal(items)
-			data := string(addedItem)
+			if err != nil {
+				return nil, fmt.Errorf("failed to marshal update items: %v", err)
+			}
 
-			data = addIndentation(data)
+			data, err := addIndentation(string(addedItem), indentation)
 			if err != nil {
-				return nil, err
+				return nil, fmt.Errorf("failed to add indentation: %v", err)
 			}
-			response.FinalOutput = response.FinalOutput + data
+			finalOutput.WriteString(data)
 			response.IsChanged = true
 		}
 	}
 
+	// Set FinalOutput to the built string
+	response.FinalOutput = finalOutput.String()
+
 	return response, nil
 }
 
-func addIndentation(data string) string {
+// addIndentation adds a certain number of spaces to the start of each line in the input string.
+// It returns a new string with the added indentation.
+func addIndentation(data string, indentation int) (string, error) {
 	scanner := bufio.NewScanner(strings.NewReader(data))
-	finalData := "\n"
+	var finalData strings.Builder
+
+	// Create the indentation string
+	spaces := strings.Repeat(" ", indentation-1)
+
+	finalData.WriteString("\n")
+
+	// Add indentation to each line
 	for scanner.Scan() {
-		finalData += "  " + scanner.Text() + "\n"
+		finalData.WriteString(spaces)
+		finalData.WriteString(scanner.Text())
+		finalData.WriteString("\n")
+	}
+
+	// Check for scanning errors
+	if err := scanner.Err(); err != nil {
+		return "", fmt.Errorf("error during scanning: %w", err)
 	}
-	return finalData
+
+	return finalData.String(), nil
 }

remediation/dependabot/dependabotconfig_test.go

@@ -38,6 +38,16 @@ func TestConfigDependabotFile(t *testing.T) {
 			Ecosystems: []Ecosystem{{"github-actions", "/", "daily"}, {"npm", "/sample", "daily"}},
 			isChanged:  true,
 		},
+		{
+			fileName:   "No-Indentation.yml",
+			Ecosystems: []Ecosystem{{"npm", "/sample", "daily"}},
+			isChanged:  true,
+		},
+		{
+			fileName:   "High-Indentation.yml",
+			Ecosystems: []Ecosystem{{"npm", "/sample", "daily"}},
+			isChanged:  true,
+		},
 	}
 
 	for _, test := range tests {

testfiles/dependabotfiles/input/High-Indentation.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+    - package-ecosystem: github-actions
+      directory: "/"
+      schedule:
+        interval: daily

testfiles/dependabotfiles/input/No-Indentation.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: daily

testfiles/dependabotfiles/input/Same-ecosystem-different-directory.yml

@@ -4,4 +4,4 @@ updates:
     # Files stored in `app` directory
     directory: "/app"
     schedule:
-      interval: "daily"
+      interval: "daily"

testfiles/dependabotfiles/output/High-Indentation.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+    - package-ecosystem: github-actions
+      directory: "/"
+      schedule:
+        interval: daily
+
+    - package-ecosystem: npm
+      directory: /sample
+      schedule:
+        interval: daily

testfiles/dependabotfiles/output/No-Indentation.yml

@@ -0,0 +1,11 @@
+version: 2
+updates:
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: daily
+
+- package-ecosystem: npm
+  directory: /sample
+  schedule:
+    interval: daily