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

Anonymous assignments must be manually posted

Error message

Anonymous assignments must be manually posted

What it means

SetAssignmentPostPolicy rejects `postManually: false` (i.e. automatic posting) when the assignment has anonymous grading enabled, raising the localized message "Anonymous assignments must be manually posted". The library enforces this because auto-releasing grades would unmask anonymous submissions; teachers must post manually once anonymity is handled.

Solutions

1. Call the mutation with postManually: true for anonymous assignments.
2. Disable anonymous grading on the assignment first if automatic posting is truly required, then set postManually: false.
3. Filter bulk scripts: skip assignments where anonymousGrading is true (or anonymous grading is locked after submissions exist).
4. Note the related rule: moderated assignments must stay manual until grades are published — handle both conditions in automation.

Example fix

// before
setAssignmentPostPolicy(input: { assignmentId: "7", postManually: false }) // anonymous assignment
// after
setAssignmentPostPolicy(input: { assignmentId: "7", postManually: true })
// or, only when anonymity is off:
// if (!assignment.anonymousGrading) setAssignmentPostPolicy(input: { assignmentId: "7", postManually: false })

const a = await client.query({ query: ASSIGNMENT_QUERY, variables: { id: assignmentId } });
const assignment = a?.data?.legacyNode ?? a?.data?.assignment;
if (assignment?.anonymousGrading && postManually === false) {
  throw new Error('anonymous assignments must be posted manually');
}

function canAutoPost(assignment) { return !!assignment && !assignment.anonymousGrading && !(assignment.moderatedGrading && !assignment.gradesPublished); }

try {
  await client.mutate({ mutation: SET_ASSIGNMENT_POST_POLICY, variables: { assignmentId, postManually } });
} catch (e) {
  if (e.graphQLErrors?.some(g => /manually posted/.test(g.message))) {
    // fall back to postManually: true and surface the constraint to the user
  } else { throw e; }
}

When it happens

Trigger: Calling setAssignmentPostPolicy with input.postManually == false on an assignment where anonymous_grading? is true (anonymous discussions, anonymously graded assignments), by a user who does hold manage_grades permission.

Common situations: Trying to switch an anonymous assignment back to automatic posting after enabling anonymity; scripts that uniformly set postManually: false across all assignments in a course; migrating post policies without checking assignment grading anonymity settings.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• A maximum of 50 assessees can be provided at once
• A maximum of 50 assessors can be provided at once
• All ConversationMessages must exist within the same…
• An assignment with that id does not exist
• Anonymous assignments cannot be hidden by section

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/3b4e603fcf2dba8d. Report an issue: GitHub.

Appendix: source

Thrown at app/graphql/mutations/set_assignment_post_policy.rb:42

  argument :assignment_id, ID, required: true, prepare: GraphQLHelpers.relay_or_legacy_id_prepare_func("Assignment")
  argument :post_comments_at, String, required: false
  argument :post_grades_at, String, required: false
  argument :post_manually, Boolean, required: true

  field :post_policy, Types::PostPolicyType, null: true

  def resolve(input:)
    begin
      assignment = AbstractAssignment.find_assignment_or_peer_review(input[:assignment_id])
      course = assignment.context
    rescue ActiveRecord::RecordNotFound
      raise GraphQL::ExecutionError, "An assignment with that id does not exist"
    end

    verify_authorized_action!(course, :manage_grades)

    if input[:post_manually] == false
      raise GraphQL::ExecutionError, I18n.t("Anonymous assignments must be manually posted") if assignment.anonymous_grading?

      if assignment.moderated_grading? && !assignment.grades_published?
        raise GraphQL::ExecutionError, I18n.t("Moderated assignments must be manually posted until grades are released")
      end
    end

    assignment.ensure_post_policy(post_manually: input[:post_manually])

    if Account.site_admin.feature_enabled?(:scheduled_feedback_releases) && input[:post_manually] == true
      is_post_params_blank = input[:post_comments_at].blank? && input[:post_grades_at].blank?

      if !is_post_params_blank
        assignment.post_policy.create_or_update_scheduled_post(input[:post_comments_at], input[:post_grades_at])
      elsif assignment.post_policy.scheduled_post && is_post_params_blank
        assignment.post_policy.remove_scheduled_post
      end
    end

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