fix(label): refuse duplicate label names unless --force

tea label create --name bug twice created a second "bug" label, after
which issue edit --add-labels bug failed as ambiguous and issue list
--label bug matched nothing. label create (and --file imports) now fail
with "label "bug" already exists in alice/project; pass --force to
update it", ignoring case; --force updates the existing label. The
ambiguity error for labels that already share a name lists their IDs.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/label_options_test.go

@@ -15,6 +15,10 @@ import (
 func TestLabelCreateAndEditExclusiveArchived(t *testing.T) {
 	calls := 0
 	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodGet {
+			_, _ = w.Write([]byte(`[]`))
+			return
+		}
 		calls++
 		var payload map[string]any
 		require.NoError(t, json.NewDecoder(r.Body).Decode(&payload))
@@ -47,3 +51,35 @@ func TestLabelCreateAndEditExclusiveArchived(t *testing.T) {
 	require.Equal(t, 2, calls)
 	require.Empty(t, diagnostics.String())
 }
+
+func TestLabelCreateRefusesDuplicateNames(t *testing.T) {
+	var changed []string
+	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method + " " + r.URL.Path {
+		case "GET /api/v1/repos/alice/project/labels":
+			if r.URL.Query().Get("page") == "1" {
+				_, _ = w.Write([]byte(`[{"id":11,"name":"bug","color":"ee0701","description":"Broken"}]`))
+				return
+			}
+			_, _ = w.Write([]byte(`[]`))
+		case "PATCH /api/v1/repos/alice/project/labels/11":
+			requirePayload(t, `{"color":"000000"}`, r.Body)
+			changed = append(changed, r.Method+" "+r.URL.Path)
+			_, _ = w.Write([]byte(`{"id":11,"name":"bug","color":"000000","description":"Broken"}`))
+		default:
+			changed = append(changed, r.Method+" "+r.URL.Path)
+			_, _ = w.Write([]byte(`{"id":12,"name":"docs"}`))
+		}
+	}))
+	defer server.Close()
+	deps, out, _ := serverDeps(t, server.URL)
+	for _, name := range []string{"bug", "BUG"} {
+		err := Execute(context.Background(), deps, []string{"label", "create", "-R", "alice/project", "--name", name, "--color", "000000"})
+		require.EqualError(t, err, `label "bug" already exists in alice/project; pass --force to update it`)
+	}
+	require.Empty(t, changed)
+	require.Empty(t, out.String())
+	require.NoError(t, Execute(context.Background(), deps, []string{"label", "create", "-R", "alice/project", "--name", "bug", "--color", "000000", "--force", "--json=id,color"}))
+	require.JSONEq(t, `{"id":11,"color":"000000"}`, out.String())
+	require.Equal(t, []string{"PATCH /api/v1/repos/alice/project/labels/11"}, changed)
+}

internal/app/labelfile_test.go

@@ -51,6 +51,10 @@ func TestLabelImportAcceptsColorPrefixedRows(t *testing.T) {
 	var created []string
 	server := newAuthenticatedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		require.Equal(t, "/api/v1/repos/alice/project/labels", r.URL.Path)
+		if r.Method == http.MethodGet {
+			_, _ = w.Write([]byte(`[]`))
+			return
+		}
 		payload, err := io.ReadAll(r.Body)
 		require.NoError(t, err)
 		var label struct{ Name string }

internal/app/metadata.go

@@ -45,7 +45,7 @@ func (a *application) labelCommand() *cobra.Command {
 	group.AddCommand(list)
 	for _, verb := range []string{"create", "edit"} {
 		var name, color, description, file string
-		var exclusive, archived bool
+		var exclusive, archived, force bool
 		command := &cobra.Command{Use: verb, Short: titleCase(verb) + " a label"}
 		if verb == "edit" {
 			command.Use += " <id>"
@@ -60,6 +60,7 @@ func (a *application) labelCommand() *cobra.Command {
 		command.Flags().BoolVar(&archived, "archived", false, "Archive the label so it cannot be newly applied")
 		if verb == "create" {
 			command.Flags().StringVar(&file, "file", "", "Import color/name rows with optional ;description")
+			command.Flags().BoolVar(&force, "force", false, "Update the label if one with the same name exists")
 		}
 		command.RunE = func(cmd *cobra.Command, args []string) error {
 			opts := services.LabelOptions{}
@@ -106,10 +107,10 @@ func (a *application) labelCommand() *cobra.Command {
 					}
 					opts.Color = &color
 				}
-				if verb == "create" || cmd.Flags().Changed("description") {
+				if cmd.Flags().Changed("description") {
 					opts.Description = &description
 				}
-				if verb == "create" || cmd.Flags().Changed("exclusive") {
+				if cmd.Flags().Changed("exclusive") {
 					opts.Exclusive = &exclusive
 				}
 				if cmd.Flags().Changed("archived") {
@@ -123,22 +124,28 @@ func (a *application) labelCommand() *cobra.Command {
 			if err != nil {
 				return err
 			}
+			var existing []services.Label
+			if verb == "create" {
+				if existing, err = s.All(cmd.Context()); err != nil {
+					return err
+				}
+			}
 			if file != "" {
 				results := []services.Label{}
 				var failures []error
 				for _, row := range imported {
-					item, err := s.Create(cmd.Context(), row)
+					item, err := s.CreateUnique(cmd.Context(), existing, row, force)
 					if err != nil {
 						failures = append(failures, fmt.Errorf("label %s: %w", *row.Name, err))
 						continue
 					}
-					results = append(results, item)
+					results, existing = append(results, item), append(existing, item)
 				}
 				return errors.Join(append(failures, writeList(a, cmd, results, labelRow))...)
 			}
 			var item services.Label
 			if verb == "create" {
-				item, err = s.Create(cmd.Context(), opts)
+				item, err = s.CreateUnique(cmd.Context(), existing, opts, force)
 			} else {
 				item, err = s.Edit(cmd.Context(), id, opts)
 			}

internal/services/label_selection.go

@@ -5,11 +5,46 @@ package services
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 )
 
-func selectLabelNames(names []string, matches map[string][]int64) ([]int64, error) {
+// Scope names the repository or organization the labels belong to.
+func (s Labels) Scope() string {
+	if s.Organization != "" {
+		return s.Organization
+	}
+	return s.Repository
+}
+
+// finder addresses the labels of the scope by ID or name (D10); byName matches numeric values as
+// names only.
+func (s Labels) finder(byName bool) NameOrID[Label] {
+	return NameOrID[Label]{Kind: "label", Scope: s.Scope(), ID: func(l Label) int64 { return l.ID }, Name: func(l Label) string { return l.Name }, ByName: byName}
+}
+
+// CreateUnique creates a label unless existing, the labels of the scope, has one with its name,
+// ignoring case. Then update edits that label with the supplied fields, keeping its name, and
+// otherwise CreateUnique fails: Gitea would create a second label that name filters cannot tell
+// apart.
+func (s Labels) CreateUnique(ctx context.Context, existing []Label, opts LabelOptions, update bool) (Label, error) {
+	current, err := s.finder(true).Find(existing, deref(opts.Name))
+	if errors.As(err, new(*NotFoundError)) {
+		return s.Create(ctx, opts)
+	}
+	if err != nil {
+		return Label{}, err
+	}
+	if !update {
+		return Label{}, &ConflictError{Reason: ReasonExists, Kind: "label", Key: strconv.Quote(current.Name), Scope: s.Scope(), Hint: "pass --force to update it"}
+	}
+	opts.Name = nil
+	return s.Edit(ctx, current.ID, opts)
+}
+
+func selectLabelNames(scope string, names []string, matches map[string][]int64) ([]int64, error) {
 	ids := make([]int64, 0, len(names))
 	seen := map[int64]bool{}
 	for _, name := range names {
@@ -18,7 +53,7 @@ func selectLabelNames(names []string, matches map[string][]int64) ([]int64, erro
 			return nil, fmt.Errorf("label %q does not exist; use tea label list", name)
 		}
 		if len(candidates) > 1 {
-			return nil, fmt.Errorf("label %q is ambiguous", name)
+			return nil, &AmbiguousError{Kind: "label", Key: strconv.Quote(name), Scope: scope, IDs: candidates}
 		}
 		if !seen[candidates[0]] {
 			ids = append(ids, candidates[0])
@@ -70,7 +105,7 @@ func (s Labels) ResolveIssueNames(ctx context.Context, names []string) ([]int64,
 		scope, name := splitLabelScope(input)
 		matches[input] = index[labelKey{scope, name}]
 	}
-	return selectLabelNames(names, matches)
+	return selectLabelNames(s.Repository, names, matches)
 }
 
 func splitLabelScope(input string) (scope, name string) {

internal/services/label_selection_test.go

@@ -66,7 +66,7 @@ func TestIssueLabelsCombineScopesWithoutSilentlyChoosingDuplicates(t *testing.T)
 	}))
 	service := Labels{Client: client, Repository: "company/project"}
 	_, err := service.ResolveIssueNames(context.Background(), []string{"bug"})
-	require.ErrorContains(t, err, "ambiguous")
+	require.EqualError(t, err, `label "bug" is ambiguous in company/project (IDs 1, 2); pass an ID`)
 	ids, err := service.ResolveIssueNames(context.Background(), []string{"org:bug", "repo:bug", "shared", "shared"})
 	require.NoError(t, err)
 	require.Equal(t, []int64{2, 1, 3}, ids)