feat(tasks): add categories templates and batch controls

db/task_categories.go

@@ -0,0 +1,201 @@
+package db
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+const MaxTaskCategoryNameRunes = 80
+
+var (
+	ErrTaskCategoryInvalid      = errors.New("invalid task category")
+	ErrTaskCategoryNameConflict = errors.New("task category name already exists")
+	ErrTaskCategoryNotFound     = errors.New("task category not found")
+	ErrTaskCategoryTaskNotFound = errors.New("task not found")
+)
+
+// TaskCategory is a globally reusable task grouping label.
+type TaskCategory struct {
+	ID        int64     `json:"id"`
+	Name      string    `json:"name"`
+	NKey      string    `json:"-"`
+	TaskCount int       `json:"task_count"`
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+const taskCategoryCols = `category.id, category.name, category.nkey,
+       count(task.id) FILTER (WHERE task.deleted_at IS NULL),
+       category.created_at, category.updated_at`
+
+func scanTaskCategory(row interface{ Scan(...any) error }) (TaskCategory, error) {
+	var category TaskCategory
+	err := row.Scan(&category.ID, &category.Name, &category.NKey, &category.TaskCount, &category.CreatedAt, &category.UpdatedAt)
+	return category, err
+}
+
+func normalizeTaskCategoryName(name string) (string, string, error) {
+	name = strings.Join(strings.Fields(name), " ")
+	if name == "" {
+		return "", "", fmt.Errorf("%w: name is required", ErrTaskCategoryInvalid)
+	}
+	if utf8.RuneCountInString(name) > MaxTaskCategoryNameRunes {
+		return "", "", fmt.Errorf("%w: name exceeds %d characters", ErrTaskCategoryInvalid, MaxTaskCategoryNameRunes)
+	}
+	return name, strings.ToLower(name), nil
+}
+
+func taskCategoryUniqueViolation(err error) bool {
+	var pgErr *pgconn.PgError
+	return errors.As(err, &pgErr) && pgErr.Code == "23505"
+}
+
+func (d *DB) CreateTaskCategory(name string) (*TaskCategory, error) {
+	name, nkey, err := normalizeTaskCategoryName(name)
+	if err != nil {
+		return nil, err
+	}
+	category, err := scanTaskCategory(d.QueryRow(`
+WITH inserted AS (
+    INSERT INTO task_categories(name, nkey)
+    VALUES ($1,$2)
+    ON CONFLICT (nkey) DO NOTHING
+    RETURNING *
+)
+SELECT inserted.id, inserted.name, inserted.nkey, 0, inserted.created_at, inserted.updated_at
+FROM inserted`, name, nkey))
+	if err == sql.ErrNoRows {
+		return nil, ErrTaskCategoryNameConflict
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}
+
+func (d *DB) ListTaskCategories() ([]*TaskCategory, error) {
+	rows, err := d.Query(`
+SELECT ` + taskCategoryCols + `
+FROM task_categories category
+LEFT JOIN tasks task ON task.category_id=category.id
+GROUP BY category.id
+ORDER BY category.name, category.id`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	categories := []*TaskCategory{}
+	for rows.Next() {
+		category, err := scanTaskCategory(rows)
+		if err != nil {
+			return nil, err
+		}
+		categories = append(categories, &category)
+	}
+	return categories, rows.Err()
+}
+
+func (d *DB) GetTaskCategory(id int64) (*TaskCategory, error) {
+	category, err := scanTaskCategory(d.QueryRow(`
+SELECT `+taskCategoryCols+`
+FROM task_categories category
+LEFT JOIN tasks task ON task.category_id=category.id
+WHERE category.id=$1
+GROUP BY category.id`, id))
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}
+
+func (d *DB) RenameTaskCategory(id int64, name string) (*TaskCategory, error) {
+	name, nkey, err := normalizeTaskCategoryName(name)
+	if err != nil {
+		return nil, err
+	}
+	category, err := scanTaskCategory(d.QueryRow(`
+WITH updated AS (
+    UPDATE task_categories SET name=$2, nkey=$3 WHERE id=$1 RETURNING *
+)
+SELECT updated.id, updated.name, updated.nkey,
+       (SELECT count(*) FROM tasks WHERE category_id=updated.id AND deleted_at IS NULL),
+       updated.created_at, updated.updated_at
+FROM updated`, id, name, nkey))
+	if err == sql.ErrNoRows {
+		return nil, ErrTaskCategoryNotFound
+	}
+	if taskCategoryUniqueViolation(err) {
+		return nil, ErrTaskCategoryNameConflict
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}
+
+// DeleteTaskCategory moves affected tasks to the uncategorized bucket through
+// the tasks.category_id ON DELETE SET NULL foreign key.
+func (d *DB) DeleteTaskCategory(id int64) (bool, error) {
+	result, err := d.Exec(`DELETE FROM task_categories WHERE id=$1`, id)
+	if err != nil {
+		return false, err
+	}
+	rows, err := result.RowsAffected()
+	return rows > 0, err
+}
+
+// SetTaskCategory updates one live task. A nil category means uncategorized.
+func (d *DB) SetTaskCategory(taskID int64, categoryID *int64) (*TaskCategory, error) {
+	if categoryID == nil {
+		result, err := d.Exec(`UPDATE tasks SET category_id=NULL WHERE id=$1 AND deleted_at IS NULL`, taskID)
+		if err != nil {
+			return nil, err
+		}
+		rows, err := result.RowsAffected()
+		if err != nil {
+			return nil, err
+		}
+		if rows == 0 {
+			return nil, ErrTaskCategoryTaskNotFound
+		}
+		return nil, nil
+	}
+	if *categoryID <= 0 {
+		return nil, fmt.Errorf("%w: category id must be positive", ErrTaskCategoryInvalid)
+	}
+	category, err := scanTaskCategory(d.QueryRow(`
+WITH selected AS (
+    SELECT * FROM task_categories WHERE id=$2
+), updated AS (
+    UPDATE tasks SET category_id=$2
+    WHERE id=$1 AND deleted_at IS NULL AND EXISTS (SELECT 1 FROM selected)
+    RETURNING id
+)
+SELECT selected.id, selected.name, selected.nkey,
+       (SELECT count(*) FROM tasks WHERE category_id=selected.id AND deleted_at IS NULL),
+       selected.created_at, selected.updated_at
+FROM selected, updated`, taskID, *categoryID))
+	if err == sql.ErrNoRows {
+		var taskExists bool
+		if checkErr := d.QueryRow(`SELECT EXISTS(SELECT 1 FROM tasks WHERE id=$1 AND deleted_at IS NULL)`, taskID).Scan(&taskExists); checkErr != nil {
+			return nil, checkErr
+		}
+		if !taskExists {
+			return nil, ErrTaskCategoryTaskNotFound
+		}
+		return nil, ErrTaskCategoryNotFound
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &category, nil
+}

db/task_categories_test.go

@@ -0,0 +1,91 @@
+package db
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestTaskCategoryCRUDAndTaskAssignment(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) - skipping", err)
+	}
+	defer d.Close()
+
+	name := fmt.Sprintf("Category %d", time.Now().UnixNano())
+	category, err := d.CreateTaskCategory("  " + strings.ReplaceAll(name, " ", "   ") + "  ")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if category.Name != name {
+		t.Fatalf("category name=%q, want %q", category.Name, name)
+	}
+	if _, err := d.CreateTaskCategory(strings.ToUpper(name)); !errors.Is(err, ErrTaskCategoryNameConflict) {
+		t.Fatalf("duplicate error=%v, want %v", err, ErrTaskCategoryNameConflict)
+	}
+
+	task, err := d.CreateTaskWithOptions("categorized task", "goal", TaskCreateOptions{CategoryID: &category.ID})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = d.DeleteTask(task.ID) })
+	loaded, err := d.GetTask(task.ID)
+	if err != nil || loaded == nil || loaded.CategoryID == nil || *loaded.CategoryID != category.ID || loaded.CategoryName != name {
+		t.Fatalf("categorized task=%+v err=%v", loaded, err)
+	}
+
+	renamed, err := d.RenameTaskCategory(category.ID, name+" renamed")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if renamed.TaskCount != 1 {
+		t.Fatalf("renamed task count=%d, want 1", renamed.TaskCount)
+	}
+	loaded, _ = d.GetTask(task.ID)
+	if loaded.CategoryName != renamed.Name {
+		t.Fatalf("task category name=%q, want %q", loaded.CategoryName, renamed.Name)
+	}
+
+	if _, err := d.SetTaskCategory(task.ID, nil); err != nil {
+		t.Fatal(err)
+	}
+	loaded, _ = d.GetTask(task.ID)
+	if loaded.CategoryID != nil || loaded.CategoryName != "" {
+		t.Fatalf("uncategorized task retained category: %+v", loaded)
+	}
+	if _, err := d.SetTaskCategory(task.ID, &category.ID); err != nil {
+		t.Fatal(err)
+	}
+	deleted, err := d.DeleteTaskCategory(category.ID)
+	if err != nil || !deleted {
+		t.Fatalf("delete category=%v err=%v", deleted, err)
+	}
+	loaded, _ = d.GetTask(task.ID)
+	if loaded.CategoryID != nil || loaded.CategoryName != "" {
+		t.Fatalf("category deletion did not clear task: %+v", loaded)
+	}
+}
+
+func TestCreateTaskRejectsMissingCategoryAtomically(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) - skipping", err)
+	}
+	defer d.Close()
+
+	missing := int64(1 << 62)
+	description := fmt.Sprintf("missing-category-%d", time.Now().UnixNano())
+	if _, err := d.CreateTaskWithOptions(description, "goal", TaskCreateOptions{CategoryID: &missing}); !errors.Is(err, ErrTaskCategoryNotFound) {
+		t.Fatalf("create error=%v, want %v", err, ErrTaskCategoryNotFound)
+	}
+	var count int
+	if err := d.QueryRow(`SELECT count(*) FROM explorations WHERE description=$1`, description).Scan(&count); err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Fatalf("failed create leaked %d exploration rows", count)
+	}
+}

db/task_templates.go

@@ -0,0 +1,231 @@
+package db
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"github.com/jackc/pgx/v5/pgconn"
+)
+
+const (
+	MaxTaskTemplateNameRunes = 120
+	MaxTaskTemplateTextRunes = 16000
+)
+
+var (
+	ErrTaskTemplateInvalid      = errors.New("invalid task template")
+	ErrTaskTemplateNameConflict = errors.New("task template name already exists")
+	ErrTaskTemplateNotFound     = errors.New("task template not found")
+)
+
+// TaskTemplate is a reusable task description and goal preset.
+type TaskTemplate struct {
+	ID          int64     `json:"id"`
+	Name        string    `json:"name"`
+	NKey        string    `json:"-"`
+	Description string    `json:"description"`
+	Goal        string    `json:"goal"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+}
+
+// TaskTemplateInput is the create/update payload after normalization.
+type TaskTemplateInput struct {
+	Name        string
+	Description string
+	Goal        string
+}
+
+// TaskTemplatePatch changes only fields whose pointers are non-nil.
+type TaskTemplatePatch struct {
+	Name        *string
+	Description *string
+	Goal        *string
+}
+
+const taskTemplateCols = `id, name, nkey, description, goal, created_at, updated_at`
+
+func scanTaskTemplate(row interface{ Scan(...any) error }) (TaskTemplate, error) {
+	var t TaskTemplate
+	err := row.Scan(&t.ID, &t.Name, &t.NKey, &t.Description, &t.Goal, &t.CreatedAt, &t.UpdatedAt)
+	return t, err
+}
+
+// taskTemplateName normalizes display whitespace while preserving the user's case.
+func taskTemplateName(name string) string { return strings.Join(strings.Fields(name), " ") }
+
+// taskTemplateNKey is the case-insensitive identity used by the unique index.
+func taskTemplateNKey(name string) string { return strings.ToLower(taskTemplateName(name)) }
+
+func normalizeTaskTemplateInput(in TaskTemplateInput) (TaskTemplateInput, string, error) {
+	in.Name = taskTemplateName(in.Name)
+	in.Description = strings.TrimSpace(in.Description)
+	in.Goal = strings.TrimSpace(in.Goal)
+	switch {
+	case in.Name == "":
+		return in, "", fmt.Errorf("%w: name is required", ErrTaskTemplateInvalid)
+	case utf8.RuneCountInString(in.Name) > MaxTaskTemplateNameRunes:
+		return in, "", fmt.Errorf("%w: name exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateNameRunes)
+	case in.Description == "":
+		return in, "", fmt.Errorf("%w: description is required", ErrTaskTemplateInvalid)
+	case utf8.RuneCountInString(in.Description) > MaxTaskTemplateTextRunes:
+		return in, "", fmt.Errorf("%w: description exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateTextRunes)
+	case in.Goal == "":
+		return in, "", fmt.Errorf("%w: goal is required", ErrTaskTemplateInvalid)
+	case utf8.RuneCountInString(in.Goal) > MaxTaskTemplateTextRunes:
+		return in, "", fmt.Errorf("%w: goal exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateTextRunes)
+	}
+	return in, taskTemplateNKey(in.Name), nil
+}
+
+func normalizeTaskTemplatePatch(patch TaskTemplatePatch) (TaskTemplatePatch, *string, error) {
+	if patch.Name == nil && patch.Description == nil && patch.Goal == nil {
+		return patch, nil, fmt.Errorf("%w: no fields supplied", ErrTaskTemplateInvalid)
+	}
+	var nkey *string
+	if patch.Name != nil {
+		name := taskTemplateName(*patch.Name)
+		if name == "" {
+			return patch, nil, fmt.Errorf("%w: name is required", ErrTaskTemplateInvalid)
+		}
+		if utf8.RuneCountInString(name) > MaxTaskTemplateNameRunes {
+			return patch, nil, fmt.Errorf("%w: name exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateNameRunes)
+		}
+		key := taskTemplateNKey(name)
+		patch.Name = &name
+		nkey = &key
+	}
+	if patch.Description != nil {
+		description := strings.TrimSpace(*patch.Description)
+		if description == "" {
+			return patch, nil, fmt.Errorf("%w: description is required", ErrTaskTemplateInvalid)
+		}
+		if utf8.RuneCountInString(description) > MaxTaskTemplateTextRunes {
+			return patch, nil, fmt.Errorf("%w: description exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateTextRunes)
+		}
+		patch.Description = &description
+	}
+	if patch.Goal != nil {
+		goal := strings.TrimSpace(*patch.Goal)
+		if goal == "" {
+			return patch, nil, fmt.Errorf("%w: goal is required", ErrTaskTemplateInvalid)
+		}
+		if utf8.RuneCountInString(goal) > MaxTaskTemplateTextRunes {
+			return patch, nil, fmt.Errorf("%w: goal exceeds %d characters", ErrTaskTemplateInvalid, MaxTaskTemplateTextRunes)
+		}
+		patch.Goal = &goal
+	}
+	return patch, nkey, nil
+}
+
+func taskTemplateUniqueViolation(err error) bool {
+	var pgErr *pgconn.PgError
+	return errors.As(err, &pgErr) && pgErr.Code == "23505"
+}
+
+// CreateTaskTemplate inserts one globally reusable preset.
+func (d *DB) CreateTaskTemplate(in TaskTemplateInput) (*TaskTemplate, error) {
+	in, nkey, err := normalizeTaskTemplateInput(in)
+	if err != nil {
+		return nil, err
+	}
+	t, err := scanTaskTemplate(d.QueryRow(`
+INSERT INTO task_templates(name, nkey, description, goal)
+VALUES ($1,$2,$3,$4)
+ON CONFLICT (nkey) DO NOTHING
+RETURNING `+taskTemplateCols, in.Name, nkey, in.Description, in.Goal))
+	if err == sql.ErrNoRows {
+		return nil, ErrTaskTemplateNameConflict
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &t, nil
+}
+
+// ListTaskTemplates returns the most recently maintained templates first.
+func (d *DB) ListTaskTemplates() ([]*TaskTemplate, error) {
+	rows, err := d.Query(`SELECT ` + taskTemplateCols + ` FROM task_templates ORDER BY updated_at DESC, id DESC`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := []*TaskTemplate{}
+	for rows.Next() {
+		t, err := scanTaskTemplate(rows)
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, &t)
+	}
+	return out, rows.Err()
+}
+
+// GetTaskTemplate returns nil when id does not exist.
+func (d *DB) GetTaskTemplate(id int64) (*TaskTemplate, error) {
+	t, err := scanTaskTemplate(d.QueryRow(`SELECT `+taskTemplateCols+` FROM task_templates WHERE id=$1`, id))
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &t, nil
+}
+
+// UpdateTaskTemplate replaces the editable fields of one preset.
+func (d *DB) UpdateTaskTemplate(id int64, in TaskTemplateInput) (*TaskTemplate, error) {
+	in, _, err := normalizeTaskTemplateInput(in)
+	if err != nil {
+		return nil, err
+	}
+	return d.PatchTaskTemplate(id, TaskTemplatePatch{
+		Name: &in.Name, Description: &in.Description, Goal: &in.Goal,
+	})
+}
+
+// PatchTaskTemplate atomically changes only the supplied fields. Keeping the
+// merge in one UPDATE prevents concurrent disjoint PATCH requests from losing
+// each other's changes.
+func (d *DB) PatchTaskTemplate(id int64, patch TaskTemplatePatch) (*TaskTemplate, error) {
+	patch, nkey, err := normalizeTaskTemplatePatch(patch)
+	if err != nil {
+		return nil, err
+	}
+	t, err := scanTaskTemplate(d.QueryRow(`UPDATE task_templates
+SET name=CASE WHEN $2 THEN $3::text ELSE name END,
+    nkey=CASE WHEN $2 THEN $4::text ELSE nkey END,
+    description=CASE WHEN $5 THEN $6::text ELSE description END,
+    goal=CASE WHEN $7 THEN $8::text ELSE goal END
+WHERE id=$1
+RETURNING `+taskTemplateCols,
+		id,
+		patch.Name != nil, patch.Name, nkey,
+		patch.Description != nil, patch.Description,
+		patch.Goal != nil, patch.Goal,
+	))
+	if err == sql.ErrNoRows {
+		return nil, ErrTaskTemplateNotFound
+	}
+	if taskTemplateUniqueViolation(err) {
+		return nil, ErrTaskTemplateNameConflict
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &t, nil
+}
+
+// DeleteTaskTemplate deletes one preset and reports whether it existed.
+func (d *DB) DeleteTaskTemplate(id int64) (bool, error) {
+	result, err := d.Exec(`DELETE FROM task_templates WHERE id=$1`, id)
+	if err != nil {
+		return false, err
+	}
+	n, err := result.RowsAffected()
+	return n > 0, err
+}

db/task_templates_test.go

@@ -0,0 +1,131 @@
+package db
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestTaskTemplateCRUDAndNormalizedUniqueness(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) — skipping", err)
+	}
+	defer d.Close()
+
+	suffix := time.Now().UnixNano()
+	name := fmt.Sprintf("Template %d", suffix)
+	created, err := d.CreateTaskTemplate(TaskTemplateInput{
+		Name:        "  " + strings.ReplaceAll(name, " ", "   ") + "  ",
+		Description: "  initial description  ",
+		Goal:        "  initial goal  ",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _, _ = d.DeleteTaskTemplate(created.ID) })
+	if created.Name != name || created.Description != "initial description" || created.Goal != "initial goal" {
+		t.Fatalf("template was not normalized: %+v", created)
+	}
+
+	if _, err := d.CreateTaskTemplate(TaskTemplateInput{
+		Name: strings.ToUpper(name), Description: "duplicate", Goal: "duplicate",
+	}); !errors.Is(err, ErrTaskTemplateNameConflict) {
+		t.Fatalf("duplicate create error = %v, want %v", err, ErrTaskTemplateNameConflict)
+	}
+
+	got, err := d.GetTaskTemplate(created.ID)
+	if err != nil || got == nil || got.Name != name {
+		t.Fatalf("GetTaskTemplate = %+v, %v", got, err)
+	}
+	listed, err := d.ListTaskTemplates()
+	if err != nil {
+		t.Fatal(err)
+	}
+	found := false
+	for _, template := range listed {
+		if template.ID == created.ID {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatalf("created template %d missing from list", created.ID)
+	}
+
+	updatedName := name + " updated"
+	updated, err := d.UpdateTaskTemplate(created.ID, TaskTemplateInput{
+		Name: updatedName, Description: "new description", Goal: "new goal",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if updated.Name != updatedName || updated.Description != "new description" || updated.Goal != "new goal" {
+		t.Fatalf("unexpected updated template: %+v", updated)
+	}
+
+	if _, err := d.CreateTaskTemplate(TaskTemplateInput{Name: "", Description: "x", Goal: "y"}); !errors.Is(err, ErrTaskTemplateInvalid) {
+		t.Fatalf("empty name error = %v, want %v", err, ErrTaskTemplateInvalid)
+	}
+	deleted, err := d.DeleteTaskTemplate(created.ID)
+	if err != nil || !deleted {
+		t.Fatalf("DeleteTaskTemplate = %v, %v", deleted, err)
+	}
+	deleted, err = d.DeleteTaskTemplate(created.ID)
+	if err != nil || deleted {
+		t.Fatalf("second DeleteTaskTemplate = %v, %v", deleted, err)
+	}
+}
+
+func TestTaskTemplateDisjointPatchesCompose(t *testing.T) {
+	d, err := Open(testDSN(t))
+	if err != nil {
+		t.Skipf("postgres unavailable (%v) - skipping", err)
+	}
+	defer d.Close()
+
+	created, err := d.CreateTaskTemplate(TaskTemplateInput{
+		Name:        fmt.Sprintf("Concurrent template %d", time.Now().UnixNano()),
+		Description: "initial description",
+		Goal:        "initial goal",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _, _ = d.DeleteTaskTemplate(created.ID) })
+
+	description := "description from concurrent patch"
+	goal := "goal from concurrent patch"
+	start := make(chan struct{})
+	errs := make(chan error, 2)
+	var wg sync.WaitGroup
+	for _, patch := range []TaskTemplatePatch{{Description: &description}, {Goal: &goal}} {
+		patch := patch
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			<-start
+			_, err := d.PatchTaskTemplate(created.ID, patch)
+			errs <- err
+		}()
+	}
+	close(start)
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	got, err := d.GetTaskTemplate(created.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got == nil || got.Description != description || got.Goal != goal {
+		t.Fatalf("disjoint patches lost an update: %+v", got)
+	}
+}