Allow empty string as valid 'deprecationReason'

src/type/__tests__/definition-test.js

@@ -183,20 +183,23 @@ describe('Type System: Objects', () => {
           type: ScalarType,
           deprecationReason: 'A terrible reason',
         },
+        baz: {
+          type: ScalarType,
+          deprecationReason: '',
+        },
       },
     });
 
-    expect(TypeWithDeprecatedField.getFields().bar).to.deep.equal({
+    expect(TypeWithDeprecatedField.getFields().bar).to.include({
       name: 'bar',
-      description: undefined,
-      type: ScalarType,
-      args: [],
-      resolve: undefined,
-      subscribe: undefined,
       isDeprecated: true,
       deprecationReason: 'A terrible reason',
-      extensions: undefined,
-      astNode: undefined,
+    });
+
+    expect(TypeWithDeprecatedField.getFields().baz).to.include({
+      name: 'baz',
+      isDeprecated: true,
+      deprecationReason: '',
     });
   });
 
@@ -519,17 +522,22 @@ describe('Type System: Enums', () => {
   it('defines an enum type with deprecated value', () => {
     const EnumTypeWithDeprecatedValue = new GraphQLEnumType({
       name: 'EnumWithDeprecatedValue',
-      values: { foo: { deprecationReason: 'Just because' } },
+      values: {
+        foo: { deprecationReason: 'Just because' },
+        bar: { deprecationReason: '' },
+      },
     });
 
-    expect(EnumTypeWithDeprecatedValue.getValues()[0]).to.deep.equal({
+    expect(EnumTypeWithDeprecatedValue.getValues()[0]).to.include({
       name: 'foo',
-      description: undefined,
       isDeprecated: true,
       deprecationReason: 'Just because',
-      value: 'foo',
-      extensions: undefined,
-      astNode: undefined,
+    });
+
+    expect(EnumTypeWithDeprecatedValue.getValues()[1]).to.include({
+      name: 'bar',
+      isDeprecated: true,
+      deprecationReason: '',
     });
   });
 

src/type/definition.js

@@ -797,7 +797,7 @@ function defineFieldMap<TSource, TContext>(
       args,
       resolve: fieldConfig.resolve,
       subscribe: fieldConfig.subscribe,
-      isDeprecated: Boolean(fieldConfig.deprecationReason),
+      isDeprecated: fieldConfig.deprecationReason != null,
       deprecationReason: fieldConfig.deprecationReason,
       extensions: fieldConfig.extensions && toObjMap(fieldConfig.extensions),
       astNode: fieldConfig.astNode,
@@ -1291,7 +1291,7 @@ function defineEnumValues(
       name: valueName,
       description: valueConfig.description,
       value: valueConfig.value !== undefined ? valueConfig.value : valueName,
-      isDeprecated: Boolean(valueConfig.deprecationReason),
+      isDeprecated: valueConfig.deprecationReason != null,
       deprecationReason: valueConfig.deprecationReason,
       extensions: valueConfig.extensions && toObjMap(valueConfig.extensions),
       astNode: valueConfig.astNode,

src/utilities/__tests__/buildClientSchema-test.js

@@ -509,6 +509,20 @@ describe('Type System: build schema from introspection', () => {
     expect(cycleIntrospection(sdl)).to.equal(sdl);
   });
 
+  it('builds a schema with empty deprecation reasons', () => {
+    const sdl = dedent`
+      type Query {
+        someField: String @deprecated(reason: "")
+      }
+
+      enum SomeEnum {
+        SOME_VALUE @deprecated(reason: "")
+      }
+    `;
+
+    expect(cycleIntrospection(sdl)).to.equal(sdl);
+  });
+
   it('can use client schema for limited execution', () => {
     const schema = buildSchema(`
       scalar CustomScalar

src/utilities/schemaPrinter.js

@@ -305,7 +305,7 @@ function printDeprecated(fieldOrEnumVal) {
   }
   const reason = fieldOrEnumVal.deprecationReason;
   const reasonAST = astFromValue(reason, GraphQLString);
-  if (reasonAST && reason !== '' && reason !== DEFAULT_DEPRECATION_REASON) {
+  if (reasonAST && reason !== DEFAULT_DEPRECATION_REASON) {
     return ' @deprecated(reason: ' + print(reasonAST) + ')';
   }
   return ' @deprecated';