Fix bug in Snippet BlobViewer GraphQL definition

app/graphql/types/snippets/blob_type.rb

@@ -14,6 +14,7 @@ module Types
 
       field :plain_data, GraphQL::STRING_TYPE,
             description: 'Blob plain highlighted data',
+            calls_gitaly: true,
             null: true
 
       field :raw_path, GraphQL::STRING_TYPE,

app/graphql/types/snippets/blob_viewer_type.rb

@@ -17,12 +17,14 @@ module Types
       field :collapsed, GraphQL::BOOLEAN_TYPE,
             description: 'Shows whether the blob should be displayed collapsed',
             method: :collapsed?,
-            null: false
+            null: false,
+            resolve: -> (viewer, _args, _ctx) { !!viewer&.collapsed? }
 
       field :too_large, GraphQL::BOOLEAN_TYPE,
             description: 'Shows whether the blob too large to be displayed',
             method: :too_large?,
-            null: false
+            null: false,
+            resolve: -> (viewer, _args, _ctx) { !!viewer&.too_large? }
 
       field :render_error, GraphQL::STRING_TYPE,
             description: 'Error rendering the blob content',

changelogs/unreleased/fj-fix-bug-snippet-blob-viewer-graphql.yml

+---
+title: Fix bug in Snippet BlobViewer GraphQL definition
+merge_request: 30927
+author:
+type: fixed

spec/graphql/types/snippets/blob_viewer_type_spec.rb

@@ -3,10 +3,91 @@
 require 'spec_helper'
 
 describe GitlabSchema.types['SnippetBlobViewer'] do
+  let_it_be(:snippet) { create(:personal_snippet, :repository) }
+  let_it_be(:blob) { snippet.repository.blob_at('HEAD', 'files/images/6049019_460s.jpg') }
+
   it 'has the correct fields' do
     expected_fields = [:type, :load_async, :too_large, :collapsed,
                        :render_error, :file_type, :loading_partial_name]
 
     expect(described_class).to have_graphql_fields(*expected_fields)
   end
+
+  it { expect(described_class.fields['type'].type).to be_non_null }
+  it { expect(described_class.fields['loadAsync'].type).to be_non_null }
+  it { expect(described_class.fields['collapsed'].type).to be_non_null }
+  it { expect(described_class.fields['tooLarge'].type).to be_non_null }
+  it { expect(described_class.fields['renderError'].type).not_to be_non_null }
+  it { expect(described_class.fields['fileType'].type).to be_non_null }
+  it { expect(described_class.fields['loadingPartialName'].type).to be_non_null }
+
+  shared_examples 'nil field converted to false' do
+    subject { GitlabSchema.execute(query, context: { current_user: snippet.author }).as_json }
+
+    before do
+      allow_next_instance_of(SnippetPresenter) do |instance|
+        allow(instance).to receive(:blob).and_return(blob)
+      end
+    end
+
+    it 'returns false' do
+      snippet_blob = subject.dig('data', 'snippets', 'edges')[0].dig('node', 'blob')
+
+      expect(snippet_blob['path']).to eq blob.path
+      expect(blob_attribute).to be_nil
+      expect(snippet_blob['simpleViewer'][attribute]).to eq false
+    end
+  end
+
+  describe 'collapsed' do
+    it_behaves_like 'nil field converted to false' do
+      let(:query) do
+        %(
+          query {
+            snippets(ids:"#{snippet.to_global_id}"){
+              edges {
+                node {
+                  blob {
+                    path
+                    simpleViewer {
+                      collapsed
+                    }
+                  }
+                }
+              }
+            }
+          }
+        )
+      end
+
+      let(:attribute) { 'collapsed' }
+      let(:blob_attribute) { blob.simple_viewer.collapsed? }
+    end
+  end
+
+  describe 'tooLarge' do
+    it_behaves_like 'nil field converted to false' do
+      let(:query) do
+        %(
+          query {
+            snippets(ids:"#{snippet.to_global_id}"){
+              edges {
+                node {
+                  blob {
+                    path
+                    simpleViewer {
+                      tooLarge
+                    }
+                  }
+                }
+              }
+            }
+          }
+        )
+      end
+
+      let(:attribute) { 'tooLarge' }
+      let(:blob_attribute) { blob.simple_viewer.too_large? }
+    end
+  end
 end