Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Haskell Package Versioning Policy.

1.5.0.1 - 2025-06-19

Fixed

• Allow any 2.x QuickCheck version.
• Make the lexer and parser safe.

1.5.0.0 - 2024-12-03

Removed

• Remove deprecated ‘gql’ quasi quoter.

Changed

• Validate the subscription root not to be an introspection field (singleFieldSubscriptionsRule).

1.4.0.0 - 2024-10-26

Changed

• Schema.Directive is extended to contain a boolean argument, representing repeatable directives. The parser can parse repeatable directive definitions. Validation allows repeatable directives.
• AST.Document.Directive is a record.
• gql quasi quoter is deprecated (moved to graphql-spice package).

Fixed

• gql quasi quoter recognizeds all GraphQL line endings (CR, LF and CRLF).

Added

• @specifiedBy directive.

1.3.0.0 - 2024-05-01

Changed

• Remove deprecated runCollectErrs, Resolution, CollectErrsT from the Error module.

1.2.0.3 - 2024-01-09

Fixed

• Fix corrupted source distribution.

1.2.0.2 - 2024-01-09

Fixed

• gql removes not only leading \n but also \r.
• Fix non nullable type string representation in executor error messages.
• Fix input objects not being coerced to lists.
• Fix used variables are not found in the properties of input objects.

1.2.0.1 - 2023-04-25

Fixed

• Support hspec 2.11.

1.2.0.0 - 2023-02-28

Added

• Schema printing.
• Semigroup and Monoid instances for AST.Document.Description.
• Support for vector 0.13.0.0 and transformers 0.6.1.0.

Fixed

• Fix resolvers returning a list in the reverse order.

Removed

• GHC 8 support.
• Cabal -json flag.
• Test.Hspec.GraphQL: moved to graphql-spice package.
• CPP ifdef WITH_JSON blocks.

1.1.0.0 - 2022-12-24

Changed

• Removed deprecated Language.GraphQL.Error functions: addErr, addErrMsg, singleError.
• Deprecate Resolution, CollectErrsT and runCollectErrs in the Error module. It was already noted in the documentation that these symbols are deprecated, now a pragma is added.
• Language.GraphQL: Added information about the json flag and switching to graphql-spice for JSON support.

Added

• Partial schema printing: operation type encoder.

1.0.3.0 - 2022-03-27

Fixed

• Index position in error path. (Index and Segment paths of a field have been swapped).
• Parsing empty list as an argument.

Added

• quickCheck Parser test for arguments. Arbitrary instances for Language.GraphQL.AST.Document.
• Enhanced query error messages. Add tests for these cases.
• Allow version 2.0 of the text package.

1.0.2.0 - 2021-12-26

Added

• Serialize instance for Type.Definition.Value.
• VariableValue instance for Type.Definition.Value.
• Json build flag, enabled by default. JSON and Aeson support can be disabled by disabling this flag.

1.0.1.0 - 2021-09-27

Added

• Custom Show instance for Type.Definition.Value (for error messages).
• Path information in errors (path to the field throwing the error).
• Deprecation notes in the Error module for Resolution, CollectErrsT and runCollectErrs. These symbols are part of the old executor and aren’t used anymore, it will be deprecated in the future and removed.
• TH module with the gql quasi quoter.

Fixed

• Error messages are more concrete, they also contain type information and wrong values, where appropriate and possible.
• If the field with an error is Non-Nullable, the error is propagated to the first nullable field, as required by the specification.

1.0.0.0 - 2021-07-04

Added

• Language.GraphQL.Execute.OrderedMap is a map data structure, that preserves insertion order.
• Language.GraphQL.Schema.schemaWithTypes constructs a complete schema, including an optional schema description and user-defined types not referenced in the schema directly (for example interface implementations).
• Language.GraphQL.Schema.description returns the optional schema description.
• All errors that can be associated with a location in the query contain location information.

Fixed

• Parser now accepts empty lists and objects.
• Parser now accepts all directive locations.
• valuesOfCorrectTypeRule doesn’t check lists recursively since the validation traverser calls it on all list items.
• valuesOfCorrectTypeRule doesn’t check objects recursively since the validation traverser calls it on all object properties.
• Validation of non-nullable values inside lists.
• executeField shouldn’t assume that a selection has only one field with a given name, but it should take the first field. The underlying cause is a wrong pattern, which (because of the laziness) is executed only if the field has arguments.

Changed

• AST.Document.Value.List and AST.Document.ConstValue.ConstList contain location information for each list item.
• Error: singleError, addErr and addErrMsg are deprecated. They are internal functions used by the executor for error handling.

0.11.1.0 - 2021-02-07

Added

• Validate.Rules:
  • overlappingFieldsCanBeMergedRule
  • possibleFragmentSpreadsRule
  • variablesInAllowedPositionRule
  • valuesOfCorrectTypeRule
• Type.Schema.implementations contains a map from interfaces and objects to interfaces they implement.
• Show instances for GraphQL type definitions in the Type modules.
• Custom Show instances for type and value representations in the AST.
• AST.Document.escape escapes a single character in a StringValue.

0.11.0.0 - 2020-11-07

Changed

• AST.Document.Selection wraps additional new types: Field, FragmentSpread and InlineFragment. Thus validation rules can be defined more concise.
• AST.Document: Argument and Directive contain token location.
• AST.Document.Argument contains the Value wrapped in the Node.
• AST.Lexer.colon and AST.Lexer.at ignore the result (it is always the
• same).
• Validate.Validation: Validation.rules was removed. Validation.rules contained the list of rules, but the executed rules shouldn’t know about other rules. rules was a part of the Validation context to pass it easier around, but since the rules are traversed once now and applied to all nodes in the tree at the beginning, it isn’t required anymore.
• Validate.Validation.Error: path is removed since it isn’t possible to get the path without executing the query.
• Error.Error: path added. It is currently always empty.
• Validate.Validation.Path was moved to Error.
• Type.Schema.Schema: data constructor is hidden, fields are accessible with freestanding functions: query, mutation, subscription, directives and types.

Added

• Validate.Validation.Rule constructors:
  • SelectionRule
  • FragmentRule
  • FragmentSpreadRule
  • ArgumentsRule
  • DirectivesRule
  • VariablesRule
  • FieldRule
• Validate.Rules:
  • fragmentsOnCompositeTypesRule
  • fragmentSpreadTargetDefinedRule
  • fragmentSpreadTypeExistenceRule
  • noUnusedFragmentsRule
  • noFragmentCyclesRule
  • uniqueArgumentNamesRule
  • uniqueDirectiveNamesRule
  • uniqueVariableNamesRule
  • variablesAreInputTypesRule
  • noUndefinedVariablesRule
  • noUndefinedVariablesRule
  • noUnusedVariablesRule
  • uniqueInputFieldNamesRule
  • fieldsOnCorrectTypeRule
  • scalarLeafsRule
  • knownArgumentNamesRule
  • knownDirectiveNamesRule
  • directivesInValidLocationsRule
  • providedRequiredArgumentsRule
  • providedRequiredInputFieldsRule
• AST.Document.Field.
• AST.Document.FragmentSpread.
• AST.Document.InlineFragment.
• AST.Document.Node.
• Type.In.Arguments: Type alias for an argument map.
• Type.Schema.Directive and Type.Schema.Directives are directive definition representation.
• Type.Schema.schema: Schema constructor.

Fixed

• Collecting existing types from the schema considers subscriptions.

Removed

• AST.Document.Alias. Use AST.Document.Name instead.

0.10.0.0 - 2020-08-29

Changed

• Test.Hspec.GraphQL.*: replace IO in the resolver with any MonadCatch.
• The Location argument of AST.Document.Definition.ExecutableDefinition was moved to OperationDefinition and FragmentDefinition since these are the actual elements that have a location in the document.
• Validate.Rules get the whole validation context (AST and schema).

Added

• Validate.Validation contains data structures and functions used by the validator and concretet rules.
• Validate.Rules: operation validation rules.

0.9.0.0 - 2020-07-24

Fixed

• Location of a parse error is returned in a singleton array with key locations.
• Parsing comments in the front of definitions.
• Some missing labels were added to the parsers, some labels were fixed to refer to the AST nodes being parsed.

Added

• AST reexports AST.Parser.
• AST.Document.Location is a token location as a line and column pair.
• Execute reexports Execute.Coerce.
• Error.Error is an error representation with a message and source location.
• Error.Response represents a result of running a GraphQL query.
• Type.Schema exports Type which lists all types possible in the schema.
• Parsing subscriptions.
• Error.ResponseEventStream, Type.Out.Resolve, Type.Out.Subscribe and Type.Out.SourceEventStream define subscription resolvers.
• Error.ResolverException is an exception that can be thrown by (field value and event stream) resolvers to signalize an error. Other exceptions will escape.
• Test.Hspec.GraphQL contains some test helpers.
• Validate contains the validator and standard rules.

Changed

• Type.Out.Resolver: Interface fields don’t have resolvers, object fields have value resolvers, root subscription type resolvers need an additional resolver that creates an event stream. Resolver represents these differences now and pairs a field with the function(s). Resolvers don’t have ExceptT, errors are handled with MonadThrow/MonadCatch.
• All code from Trans is moved to Type.Out and exported by Type and Type.Out.
• AST.Core contained only Arguments which was moved to Type.Definition. AST provides now only functionality related to parsing and encoding, as it should be.
• Execute.execute takes an additional argument, a possible operation name and returns either a stream or the response.
• Error module was changed to work with dedicated types for errors and the response instead of JSON.
• graphqlSubs takes an additional argument, the operation name. The type of variable names is changed back to JSON since it is a common format and it saves additional conversions. Custom format still can be used with the underlying functions (in the Execute module). The function returns either a a stream or the resolved value.
• graphql returns either a stream or the resolved value.
• The constraint of the base monad was changed to MonadCatch (and it implies MonadThrow).

Removed

• Trans.ActionT is an unneeded layer of complexity. Type.Out.Resolver represents possible resolver configurations.
• Execute.executeWithName. Execute.execute takes the operation name and completely replaces executeWithName.

0.8.0.0 - 2020-06-20

Fixed

• The parser rejects variables when parsing defaultValue (DefaultValue). The specification defines default values as Value with const parameter and constants cannot be variables. AST.Document.ConstValue was added, AST.Document.ObjectField was modified.
• AST transformation should never fail.
  • Arguments and fields with a missing variable as value should be left out.
  • Invalid (recusrive or non-existing) fragments should be skipped.
• Argument value coercion.
• Variable value coercion.
• Result coercion.
• The executor should skip the fields missing in the object type and not fail.
• Merging subselections.

Changed

• Schema.Resolver was moved to Type.Out, it is a field and resolver function pair.
• AST.Core.Value was moved into Type.Definition. These values are used only in the execution and type system, it is not a part of the parsing tree.
• Type module is superseded by Type.Out. This module contains now only exports from other module that complete Type.In and Type.Out exports.
• Error.CollectErrsT contains the new Resolution data structure. Resolution represents the state used by the executor. It contains all types defined in the schema and collects the thrown errors.

Added

• Type.Definition contains base type system definition, e.g. Enums and Scalars.
• Type.Schema describes a schema. Both public functions that execute queries accept a Schema now instead of a HashMap. The execution fails if the root operation doesn’t match the root Query type in the schema.
• Type.In and Type.Out contain definitions for input and output types.
• Execute.Coerce defines a typeclass responsible for input, variable value coercion. It decouples us a bit from JSON since any format can be used to pass query variables. Execution functions accept (HashMap Name a) instead of Subs, where a is an instance of VariableValue.

Removed

• Schema.scalar, Schema.wrappedScalar. They accepted everything can be converted to JSON and JSON is not suitable as an internal representation for GraphQL. E.g. GraphQL distinguishes between Floats and Integers.
• Schema.wrappedObject, Schema.object, Schema.resolversToMap. There is no need in special functions to construct field resolvers anymore, resolvers are normal functions attached to the fields in the schema representation.
• Schema.resolve is superseded by Execute.Execution.
• Error.runAppendErrs isn’t used anywhere.
• AST.Core: Document, Directive, Field, Fragment, Selection, Alias TypeCondition were modified, moved into Execute.Transform.Document and made private. These types describe intermediate representation used by the executor internally. Moving was required to avoid cyclic dependencies between the executor and type system.
• AST.Core doesn’t reexports anything.

0.7.0.0 - 2020-05-11

Fixed

• Result of null encoding
• Block strings encoding
• Result of tab and newline encoding

Added

• AST for the GraphQL schema.
• Type system definition parser.
• Trans.argument.
• Schema extension parser.
• Contributing guidelines.
• Schema.resolversToMap (intended to be used internally).

Changed

• Rename AST.Definition into AST.Document.ExecutableDefinition. AST.Document.TypeSystemDefinition and AST.Document.TypeSystemExtension can also be definitions.
• Move all AST data to AST.Document and reexport them.
• Rename AST.OperationSelectionSet to AST.Document.SelectionSet.
• Make Schema.Subs a Data.HashMap.Strict (was a function key -> Maybe value before).
• Make AST.Lexer.at a text (symbol) parser. It was a char before and is symbol "@" now.
• Replace MonadIO with a plain Monad. Since the tests don’t use IO, set the inner monad to Identity.
• NonEmpty (Resolver m) is now HashMap Text (NonEmpty (Resolver m)). Root operation type can be any type, therefore a hashmap is needed. Since types cannot be empty, we save the list of resolvers in the type as a non-empty list. Currently only “Query” and “Mutation” are supported as types. For more schema support is required. The executor checks now if the type in the query matches the type of the provided root resolvers.

Removed

• AST.Field, AST.InlineFragment and AST.FragmentSpread. These types are only used in AST.Selection and AST.Selection contains now 3 corresponding data constructors, Field, InlineFragment and FragmentSpread, instead of separate types. It simplifies pattern matching and doesn’t make the code less typesafe.
• Schema.scalarA.
• Schema.wrappedScalarA.
• Schema.wrappedObjectA.
• Schema.objectA.
• AST.Argument. Replaced with AST.Arguments which holds all arguments as a key/value map.

0.6.1.0 - 2019-12-23

Fixed

• Parsing multiple string arguments, such as login(username: "username", password: "password") would fail on the comma due to strings not having a space consumer.
• Fragment spread is evaluated based on the __typename resolver. If the resolver is missing, it is assumed that the type condition is satisfied (all fragments are included).
• Escaping characters during encoding.

Added

• Directive support (@skip and @include).
• Pretifying multi-line string arguments as block strings.

0.6.0.0 - 2019-11-27

Changed

• Language.GraphQL.Encoder moved to Language.GraphQL.AST.Encoder.
• Language.GraphQL.Parser moved to Language.GraphQL.AST.Parser.
• Language.GraphQL.Lexer moved to Language.GraphQL.AST.Lexer.
• All Language.GraphQL.AST.Value data constructor prefixes were removed. The module should be imported qualified.
• All Language.GraphQL.AST.Core.Value data constructor prefixes were removed. The module should be imported qualified.
• Language.GraphQL.AST.Core.Object is now just a HashMap.
• Language.GraphQL.AST.Transform is isn’t exposed publically anymore.
• Language.GraphQL.Schema.resolve accepts a selection Seq (Data.Sequence) instead of a list. Selections are stored as sequences internally as well.
• Add a reader instance to the resolver’s monad stack. The Reader contains a Name/Value hashmap, which will contain resolver arguments.

Added

• Nested fragment support.

Fixed

• Consume ignored tokens after $ and !. I mistakenly assumed that $variable is a single token, same as Type! is a single token. This is not the case, for example Variable is defined as $ Name, so these are two tokens, therefore whitespaces and commas after $ and ! should be consumed.

Improved

• Language.GraphQL.AST.Parser.type_: Try type parsers in a variable definition in a different order to avoid using but.

Removed

• Language.GraphQL.AST.Arguments. Use [Language.GraphQL.AST.Argument] instead.
• Language.GraphQL.AST.Directives. Use [Language.GraphQL.AST.Directives] instead.
• Language.GraphQL.AST.VariableDefinitions. Use [Language.GraphQL.AST.VariableDefinition] instead.
• Language.GraphQL.AST.FragmentName. Use Language.GraphQL.AST.Name instead.
• Language.GraphQL.Execute.Schema - It was a resolver list, not a schema.
• Language.GraphQL.Schema: enum, enumA, wrappedEnum and wrappedEnumA. Use scalar, scalarA, wrappedScalar and wrappedScalarA instead.

0.5.1.0 - 2019-10-22

Deprecated

• Language.GraphQL.AST.Arguments. Use [Language.GraphQL.AST.Argument] instead.
• Language.GraphQL.AST.Directives. Use [Language.GraphQL.AST.Directives] instead.
• Language.GraphQL.AST.VariableDefinitions. Use [Language.GraphQL.AST.VariableDefinition] instead.

Added

• Module documentation.
• Inline fragment support.

Fixed

• Top-level fragments.
• Fragment for execution is chosen based on the type.

0.5.0.1 - 2019-09-10

Added

• Minimal documentation for all public symbols.

Deprecated

• Language.GraphQL.AST.FragmentName. Replaced with Language.GraphQL.AST.Name.
• Language.GraphQL.Execute.Schema - It is not a schema (at least not a complete one), but a resolver list, and the resolvers should be provided by the user separately, because the schema can originate from a GraphQL document. Schema name should be free to provide a data type for the real schema later.
• Language.GraphQL.Schema: enum, enumA, wrappedEnum and wrappedEnumA. There are actually only two generic types in GraphQL: Scalars and objects. Enum is a scalar value.

Fixed

• Parsing block string values.

0.5.0.0 - 2019-08-14

Added

• executeWithName executes an operation with the given name.
• Export Language.GraphQL.Encoder.definition, Language.GraphQL.Encoder.type' and Language.GraphQL.Encoder.directive.
• Export Language.GraphQL.Encoder.value. Escapes \ and “ in strings now.

Changed

• Operation includes now possible operation name which allows to support documents with multiple operations.
• Language.GraphQL.Encoder.document and other encoding functions take a Formatter as argument to distinguish between minified and pretty printing.
• All encoder functions return Data.Text.Lazy.

Removed

• Unused Language.GraphQL.Encoder.spaced.

0.4.0.0 - 2019-07-23

Added

• Support for mutations.
• Error handling (with monad transformers).
• Nullable types.
• Arbitrary nested lists support.
• Potential BOM header parsing.

Changed

• attoparsec is replaced with megaparsec.
• The library is now under Language.GraphQL (instead of Data.GraphQL).
• HUnit and tasty are replaced with Hspec.
• Alternative/MonadPlus resolver constraints are replaced with MonadIO.

Removed

• Duplicates from Language.GraphQL.AST already available in Language.GraphQL.AST.Core.
• All module exports are now explicit, so private and help functions aren’t exported anymore.

0.3 - 2015-09-22

Changed

• Exact match numeric types to spec.
• Names follow now the spec.
• AST slightly different for better readability or easier parsing.
• Replace golden test for test to validate parsing/encoding.

Added

• Parsing errors in all cases where Alternative is used.
• GraphQL encoder.

Fixed

• Expect braces inputValueDefinitions instead of parens when parsing.

0.2.1 - 2015-09-16

Fixed

• Include data files for golden tests in Cabal package.
• Support for ghc-7.8.

0.2 - 2015-09-14

Added

• Rudimentary parser for GraphQL which successfully parses the sample file kitchen-sink.graphql from graphql-js tests.
• Golden test for kitchen-sink.grahql parsing.

Changed

• Many optional data types in GraphQl didn’t need to be wrapped in a Maybe.
• Some newtypes became type synonyms for easier parsing.

0.1 - 2015-09-12

Added

• Data types for the GraphQL language.