refactor(config): return errors instead of exiting the process

cmd/addgroupguests.go

@@ -35,7 +35,10 @@ Example:
 			return
 		}
 
-		courseConfig := config.GetCourseConfig(courseName)
+		courseConfig, err := config.GetCourseConfig(courseName)
+		if err != nil {
+			er(err)
+		}
 		subgroupPath := config.GetCourseSubgroupPath(courseName)
 
 		fmt.Printf("Course: %s\n", courseName)
@@ -64,7 +67,7 @@ Example:
 		fmt.Scanln() //nolint:errcheck
 
 		c := gitlab.NewClient()
-		err := c.AddGroupGuests(courseName)
+		err = c.AddGroupGuests(courseName)
 		if err != nil {
 			fmt.Printf("Error: %v\n", err)
 			return

cmd/archive.go

@@ -21,7 +21,10 @@ var (
 		Long:  `Archive or unarchive repositories.`,
 		Args:  cobra.MinimumNArgs(2), //nolint:gomnd
 		Run: func(cmd *cobra.Command, args []string) {
-			assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			if err != nil {
+				er(err)
+			}
 			assignmentConfig.Show()
 			fmt.Println(aurora.Magenta("Config okay? Press 'Enter' to continue or 'Ctrl-C' to stop ..."))
 			fmt.Scanln() //nolint:errcheck

cmd/check.go

@@ -20,7 +20,10 @@ var checkCmd = &cobra.Command{
 		viper.Set("show-success", true)
 		c := gitlab.NewClient()
 		if len(args) == 1 {
-			cfg := config.GetCourseConfig(args[0])
+			cfg, err := config.GetCourseConfig(args[0])
+			if err != nil {
+				er(err)
+			}
 			if cfg != nil {
 				c.CheckCourse(cfg)
 			}

cmd/clone.go

@@ -17,7 +17,10 @@ var (
 		You can specify students or groups in order to clone only for these.`,
 		Args: cobra.MinimumNArgs(2), //nolint:gomnd
 		Run: func(cmd *cobra.Command, args []string) {
-			assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			if err != nil {
+				er(err)
+			}
 			if len(Branch) > 0 {
 				assignmentConfig.SetBranch(Branch)
 			}

cmd/delete.go

@@ -20,7 +20,10 @@ var deleteCmd = &cobra.Command{
 You can specify students or groups in order to delete only for these.`,
 	Args: cobra.MinimumNArgs(2), //nolint:gomnd
 	Run: func(cmd *cobra.Command, args []string) {
-		assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		if err != nil {
+			er(err)
+		}
 		assignmentConfig.Show()
 		fmt.Println(aurora.Magenta("Do you really want to delete the repos? Press 'Enter' to continue or 'Ctrl-C' to stop ..."))
 		fmt.Scanln() //nolint:errcheck

cmd/generate.go

@@ -21,7 +21,10 @@ You can specify students or groups in order to generate only for these.
 A student needs to exist on GitLab, a group needs to exist in the configuration file.`,
 	Args: cobra.MinimumNArgs(2), //nolint:gomnd
 	Run: func(cmd *cobra.Command, args []string) {
-		assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		if err != nil {
+			er(err)
+		}
 		assignmentConfig.Show()
 		fmt.Println(aurora.Magenta("Config okay? Press 'Enter' to continue or 'Ctrl-C' to stop ..."))
 		fmt.Scanln() //nolint:errcheck

cmd/protect.go

@@ -21,7 +21,10 @@ var (
 		Long:  `Protect branch for exisiting repositories.`,
 		Args:  cobra.MinimumNArgs(2), //nolint:gomnd
 		Run: func(cmd *cobra.Command, args []string) {
-			assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			if err != nil {
+				er(err)
+			}
 			if len(ProtectBranch) > 0 {
 				assignmentConfig.SetProtectToBranch(ProtectBranch)
 			}

cmd/push.go

@@ -20,12 +20,15 @@ var pushCmd = &cobra.Command{
 		course := args[0]
 		assignment := args[1]
 		branchname := args[2]
-		assignmentConfig := config.GetAssignmentConfig(course, assignment, args[3:]...)
+		assignmentConfig, err := config.GetAssignmentConfig(course, assignment, args[3:]...)
+		if err != nil {
+			er(err)
+		}
 		assignmentConfig.Show()
 		fmt.Println(aurora.Magenta("Config okay? Press 'Enter' to continue or 'Ctrl-C' to stop ..."))
 		fmt.Scanln() //nolint:errcheck
 		c := gitlab.NewClient()
-		err := c.Push(assignmentConfig, branchname)
+		err = c.Push(assignmentConfig, branchname)
 		if err != nil {
 			fmt.Printf("error: %s", err.Error())
 		}

cmd/report.go

@@ -63,7 +63,10 @@ var (
 				}
 				return
 			}
-			assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			if err != nil {
+				er(err)
+			}
 			c := gitlab.NewClient()
 			if Json {
 				c.ReportJSON(assignmentConfig, output)

cmd/setaccess.go

@@ -21,7 +21,10 @@ var (
 		Long:  `Set access level for exisiting repositories.`,
 		Args:  cobra.MinimumNArgs(2), //nolint:gomnd
 		Run: func(cmd *cobra.Command, args []string) {
-			assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+			if err != nil {
+				er(err)
+			}
 			if len(Level) > 0 {
 				assignmentConfig.SetAccessLevel(Level)
 			}

cmd/show.go

@@ -15,7 +15,10 @@ var showConfigCmd = &cobra.Command{
 	Long:  `Show config of an assignment`,
 	Args:  cobra.MinimumNArgs(2),
 	Run: func(cmd *cobra.Command, args []string) {
-		cfg := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		cfg, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		if err != nil {
+			er(err)
+		}
 		cfg.Show()
 	},
 }

cmd/update.go

@@ -22,7 +22,10 @@ var updateCmd = &cobra.Command{
 	Use only with fresh, i.e. untouched, repositories.`,
 	Args: cobra.MinimumNArgs(2), //nolint:gomnd
 	Run: func(cmd *cobra.Command, args []string) {
-		assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+		if err != nil {
+			er(err)
+		}
 		assignmentConfig.Show()
 		fmt.Println(aurora.Red("Heads up! Use only with untouched projects."))
 		fmt.Println(aurora.Magenta("Config okay? Press 'Enter' to continue or 'Ctrl-C' to stop ..."))

cmd/urls.go

@@ -16,7 +16,10 @@ var (
 			if len(args) == 1 {
 				config.GetCourseURL(args[0])
 			} else {
-				assignmentConfig := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+				assignmentConfig, err := config.GetAssignmentConfig(args[0], args[1], args[2:]...)
+				if err != nil {
+					er(err)
+				}
 				if startercode {
 					assignmentConfig.StartercodeURL()
 				} else {

config/assignment.go

@@ -5,41 +5,35 @@ import (
 	"strings"
 
 	"github.com/go-viper/mapstructure/v2"
-	"github.com/rs/zerolog/log"
 	"github.com/spf13/viper"
 )
 
 func GetCourseURL(course string) {
 	fmt.Printf("%s/%s\n", viper.GetString("gitlab.host"), coursePath(course))
 }
 
-func GetAssignmentConfig(course, assignment string, onlyForStudentsOrGroups ...string) *AssignmentConfig {
+func GetAssignmentConfig(course, assignment string, onlyForStudentsOrGroups ...string) (*AssignmentConfig, error) {
 	if !viper.IsSet(course) {
-		log.Fatal().
-			Str("course", course).
-			Msg("configuration for course not found")
+		return nil, fmt.Errorf("configuration for course %s not found", course)
 	}
 
 	if !viper.IsSet(course + "." + assignment) {
-		log.Fatal().
-			Str("course", course).
-			Str("assignment", assignment).
-			Msg("configuration for assignment not found")
+		return nil, fmt.Errorf("course %s: configuration for assignment %s not found", course, assignment)
 	}
 
 	// Abstract assignments are bases for `extends` only and must not be used
 	// directly. Checked before resolving inheritance so the (own) flag is read,
 	// not an inherited one.
 	if assignmentIsAbstract(course, assignment) {
-		log.Fatal().
-			Str("course", course).
-			Str("assignment", assignment).
-			Msg("assignment is abstract (a base for 'extends') and cannot be used directly")
+		return nil, fmt.Errorf("course %s: assignment %s is abstract (a base for 'extends') and cannot be used directly",
+			course, assignment)
 	}
 
 	// Resolve `extends` inheritance before reading any fields so the rest of
 	// the config loading sees the merged, effective configuration.
-	resolveAssignmentInheritance(course, assignment)
+	if err := resolveAssignmentInheritance(course, assignment); err != nil {
+		return nil, err
+	}
 
 	assignmentKey := course + "." + assignment
 	per := per(assignmentKey)
@@ -53,8 +47,14 @@ func GetAssignmentConfig(course, assignment string, onlyForStudentsOrGroups ...s
 		containerRegistry = true
 	}
 
-	starter := startercode(assignmentKey)
-	branchRules := branches(assignmentKey, starter)
+	starter, err := startercode(assignmentKey)
+	if err != nil {
+		return nil, err
+	}
+	branchRules, err := branches(assignmentKey, starter)
+	if err != nil {
+		return nil, err
+	}
 	defaultCloneBranch := defaultBranch(branchRules, "main")
 
 	deferredBranches := make(map[string]*DeferredBranch)
@@ -93,6 +93,15 @@ func GetAssignmentConfig(course, assignment string, onlyForStudentsOrGroups ...s
 		}
 	}
 
+	mr, err := mergeRequest(assignmentKey)
+	if err != nil {
+		return nil, err
+	}
+	seed, err := seeder(assignmentKey)
+	if err != nil {
+		return nil, err
+	}
+
 	assignmentConfig := &AssignmentConfig{
 		Course:                course,
 		Name:                  assignment,
@@ -109,19 +118,19 @@ func GetAssignmentConfig(course, assignment string, onlyForStudentsOrGroups ...s
 		Description:       description(assignmentKey),
 		ContainerRegistry: containerRegistry,
 		AccessLevel:       accessLevel(assignmentKey),
-		MergeRequest:      mergeRequest(assignmentKey),
+		MergeRequest:      mr,
 		Branches:          branchRules,
 		Issues:            issues(assignmentKey),
 		Students:          students(per, course, assignment, onlyForStudentsOrGroups...),
 		Groups:            groups(per, course, assignment, onlyForStudentsOrGroups...),
 		Startercode:       starter,
 		Clone:             clone(assignmentKey, defaultCloneBranch),
 		Release:           release,
-		Seeder:            seeder(assignmentKey),
+		Seeder:            seed,
 		DeferredBranches:  deferredBranches,
 	}
 
-	return assignmentConfig
+	return assignmentConfig, nil
 }
 
 // Using email addresses instead of usernames/user-id's results in @ in the student's name.
@@ -215,7 +224,7 @@ func description(assignmentKey string) string {
 	return description
 }
 
-func mergeRequest(assignmentKey string) *MergeRequest {
+func mergeRequest(assignmentKey string) (*MergeRequest, error) {
 	mergeMethod := MergeCommit
 	switch viper.GetString(assignmentKey + ".mergeRequest.mergeMethod") {
 	case "semi_linear":
@@ -238,28 +247,37 @@ func mergeRequest(assignmentKey string) *MergeRequest {
 		squashOption = SquashDefaultOff
 	}
 
+	approvals, err := mergeRequestApprovals(assignmentKey)
+	if err != nil {
+		return nil, err
+	}
+	settings, err := mergeRequestApprovalSettings(assignmentKey)
+	if err != nil {
+		return nil, err
+	}
+
 	return &MergeRequest{
 		MergeMethod:                   mergeMethod,
 		SquashOption:                  squashOption,
 		PipelineMustSucceed:           viper.GetBool(assignmentKey + ".mergeRequest.pipeline"),
 		SkippedPipelinesAreSuccessful: viper.GetBool(assignmentKey + ".mergeRequest.skippedPipelinesAreSuccessful"),
 		AllThreadsMustBeResolved:      viper.GetBool(assignmentKey + ".mergeRequest.allThreadsMustBeResolved"),
 		StatusChecksMustSucceed:       viper.GetBool(assignmentKey + ".mergeRequest.statusChecksMustSucceed"),
-		Approvals:                     mergeRequestApprovals(assignmentKey),
-		ApprovalSettings:              mergeRequestApprovalSettings(assignmentKey),
-	}
+		Approvals:                     approvals,
+		ApprovalSettings:              settings,
+	}, nil
 }
 
-func mergeRequestApprovals(assignmentKey string) []MergeRequestApprovalRule {
+func mergeRequestApprovals(assignmentKey string) ([]MergeRequestApprovalRule, error) {
 	raw := viper.Get(assignmentKey + ".mergeRequest.approvals")
 	raw = extractMergeRequestApprovalRulesRaw(raw)
 	raw = normalizeMergeRequestApprovalConfigKeys(raw)
 	if raw == nil {
-		return nil
+		return nil, nil
 	}
 
 	if containsLegacyApprovalUsersKey(raw) {
-		log.Fatal().Str("assignmentKey", assignmentKey).Msg("mergeRequest.approvals.rules[].users is no longer supported; use usernames")
+		return nil, fmt.Errorf("%s: mergeRequest.approvals.rules[].users is no longer supported; use usernames", assignmentKey)
 	}
 
 	var configured []MergeRequestApprovalRule
@@ -269,10 +287,10 @@ func mergeRequestApprovals(assignmentKey string) []MergeRequestApprovalRule {
 		WeaklyTypedInput: true,
 	})
 	if err != nil {
-		log.Fatal().Err(err).Str("assignmentKey", assignmentKey).Msg("cannot create mergeRequest.approvals decoder")
+		return nil, fmt.Errorf("%s: cannot create mergeRequest.approvals decoder: %w", assignmentKey, err)
 	}
 	if err := decoder.Decode(raw); err != nil {
-		log.Fatal().Err(err).Str("assignmentKey", assignmentKey).Msg("cannot parse mergeRequest.approvals config")
+		return nil, fmt.Errorf("%s: cannot parse mergeRequest.approvals config: %w", assignmentKey, err)
 	}
 
 	normalized := make([]MergeRequestApprovalRule, 0, len(configured))
@@ -327,7 +345,7 @@ func mergeRequestApprovals(assignmentKey string) []MergeRequestApprovalRule {
 		normalized = append(normalized, rule)
 	}
 
-	return normalized
+	return normalized, nil
 }
 
 func extractMergeRequestApprovalRulesRaw(value any) any {
@@ -374,10 +392,10 @@ func containsLegacyApprovalUsersKey(value any) bool {
 	}
 }
 
-func mergeRequestApprovalSettings(assignmentKey string) *MergeRequestApprovalSettings {
+func mergeRequestApprovalSettings(assignmentKey string) (*MergeRequestApprovalSettings, error) {
 	prefix := assignmentKey + ".mergeRequest.approvals.settings"
 	if !viper.IsSet(prefix) {
-		return nil
+		return nil, nil
 	}
 
 	settings := &MergeRequestApprovalSettings{}
@@ -404,10 +422,9 @@ func mergeRequestApprovalSettings(assignmentKey string) *MergeRequestApprovalSet
 		case ApprovalKeepApprovals, ApprovalRemoveAllApprovals, ApprovalRemoveCodeOwnerApprovalsIfFilesChanged:
 			settings.WhenCommitAdded = &v
 		default:
-			log.Fatal().
-				Str("assignmentKey", assignmentKey).
-				Str("whenCommitAdded", string(v)).
-				Msg("invalid mergeRequest.approvals.settings.whenCommitAdded")
+			return nil, fmt.Errorf("%s: invalid mergeRequest.approvals.settings.whenCommitAdded %q, must be one of %s, %s, %s",
+				assignmentKey, v,
+				ApprovalKeepApprovals, ApprovalRemoveAllApprovals, ApprovalRemoveCodeOwnerApprovalsIfFilesChanged)
 		}
 	}
 
@@ -416,10 +433,10 @@ func mergeRequestApprovalSettings(assignmentKey string) *MergeRequestApprovalSet
 		settings.PreventEditingApprovalRulesInMergeRequests == nil &&
 		settings.RequireUserReauthenticationToApprove == nil &&
 		settings.WhenCommitAdded == nil {
-		return nil
+		return nil, nil
 	}
 
-	return settings
+	return settings, nil
 }
 
 func normalizeMergeRequestApprovalConfigKeys(value any) any {