What causes "not found" in instructure/canvas-lms?

Verify the assignment exists: Assignment.find(id) in console, and that it is in the same course.

instructure/canvas-lms · error · GraphQL::ExecutionError

not found

Error message

not found

What it means

PostAssignmentGrades mutation resolves the assignment via AbstractAssignment.find_assignment_or_peer_review; if the id does not resolve (or course/section lookup raises RecordNotFound inside the same begin block), it is translated into a generic GraphQL 'not found' ExecutionError.

Solutions

Verify the assignment exists: Assignment.find(id) in console, and that it is in the same course.
Use the assignment's global or correct-shard id; confirm peer-review sub-assignments only where intended.
Check the assignment was not deleted (workflow_state != 'deleted') and re-fetch fresh ids.

Example fix

// before
postAssignmentGrades(input: {assignmentId: "1234", ...}) // deleted/stale id
// after
const assignment = await fetchAssignment(id); // 404-check before posting
if (!assignment) return; // surface a friendly 'assignment no longer exists' message

Defensive patterns

Strategy: validation

Validate before calling

if (!assignmentId) throw new Error('assignmentId required');
const assignment = await fetchAssignment(assignmentId); // expect 200
if (!assignment) return notFound();

Type guard

const isValidAssignment = (a) => a && typeof a.id === 'string' && a.id.length > 0;

Try / catch

try { await postAssignmentGrades({input}); } catch (e) { if (e.message === 'not found') notifyStaleAssignment(); else throw e; }

Prevention

Re-fetch assignment ids from the API instead of caching them across sessions.
Use global ids when crossing shard boundaries.
Handle deletions in the UI so stale ids cannot be submitted.

When it happens

Trigger: Posting grades with an assignmentId that is deleted, nonexistent, belongs to another course/shard, or is not an assignment or peer-review sub-assignment.

Common situations: Stale client-side IDs after an assignment deletion; copying IDs across Canvas shards/environments; passing a discussion topic or quiz id instead of its assignment id.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/1dce8eb9a92f8964. Report an issue: GitHub.

Appendix: source

Thrown at app/graphql/mutations/post_assignment_grades.rb:40

  graphql_name "PostAssignmentGrades"

  argument :assignment_id, ID, required: true, prepare: GraphQLHelpers.relay_or_legacy_id_prepare_func("Assignment")
  argument :graded_only, Boolean, required: false
  argument :only_student_ids, [ID], required: false, prepare: GraphQLHelpers.relay_or_legacy_ids_prepare_func("User")
  argument :section_ids, [ID], required: false, prepare: GraphQLHelpers.relay_or_legacy_ids_prepare_func("Section")
  argument :skip_student_ids, [ID], required: false, prepare: GraphQLHelpers.relay_or_legacy_ids_prepare_func("User")

  field :assignment, Types::AssignmentType, null: true
  field :progress, Types::ProgressType, null: true
  field :sections, [Types::SectionType], null: true

  def resolve(input:)
    begin
      assignment = AbstractAssignment.find_assignment_or_peer_review(input[:assignment_id])
      course = assignment.context
      sections = input[:section_ids] ? course.course_sections.where(id: input[:section_ids]) : nil
    rescue ActiveRecord::RecordNotFound
      raise GraphQL::ExecutionError, "not found"
    end

    verify_authorized_action!(assignment, :grade)

    unless assignment.grades_published?
      raise GraphQL::ExecutionError, "Assignments under moderation cannot be posted before grades are published"
    end
    raise GraphQL::ExecutionError, "Anonymous assignments cannot be posted by section" if sections && assignment.anonymous_grading?

    if input[:graded_only] && assignment.anonymous_grading
      raise GraphQL::ExecutionError, "Anonymous assignments cannot be posted by graded only"
    end

    if input[:only_student_ids] && input[:skip_student_ids]
      raise GraphQL::ExecutionError, I18n.t("{a} and {b} cannot be used together", a: "only_student_ids", b: "skip_student_ids")
    end

    visible_enrollments = course.apply_enrollment_visibility(course.student_enrollments, current_user, sections)

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