Support for embedded struct type in resolver

Adding example and documentation for how to create custom error
 implementations which include `extensions` within their `error` payload

…tom-errors

Add Example of Custom Errors

Print context to panic log

Producing clearer error messages when field input arguments are
 implemented by code:

 * Which does not match the schema e.g. missing field; or
 * Function missing struct wrapper for field arguments

…input-resolver-mismatch-with-schema

Clarify errors for mismatching input implementation

…ntrypoints-without-explicit-schema

Allow `schema` to be omitted when using default root op names

Fix graph-gophers#357 - Allow passing integers as arguments to graphql.Time parameters

Multi-line descriptions need to have their common indentation level
 (which results from indentation of that part of the schema, rather than
 being intentional for the description text) removed to ensure the
 descriptions use the correct value, are formatted correctly etc

This is to meet the condition documented in the GraphQL spec:

https://graphql.github.io/graphql-spec/June2018/#sec-String-Value

> Since block strings represent freeform text often used in indented
>  positions, the string value semantics of a block string excludes
>  uniform indentation and blank initial and trailing lines via
>  BlockStringValue().

…tation-from-blockstring-descriptions

Strip Common Indentation from BlockString Descriptions

Syntax highlighting fixed in README

Fixed small punctuation and added my walkthrough package

Adding walkthrough

…from-query

Use operationName from query if missing from POST

Add support for directives in schema parser

Fix SIGSEGV when client subs to multiple fields

In previous versions of this code, this validation would exit when it
encountered a fragment legitimately used twice. This bugfix skips the recursion
but does not stop progress altogether allowing other fragments to be marked as
used.

bugfix: correctly determine fragment usage

It uses the current capacity of the limiter as a hint as this is set
based on the maxParallelism field on the schema.

This adds a tiny bit more information to the error messages produced
when unmarshaling an input value to an ID or Time fails.

Fixes graph-gophers#307

Add short descriptions for different schema options.
Move community examples to wiki.
Add companies that use this library.

Improve README.md graph-gophers#307

…-error-msg

More descriptive error when unmarshaling ID/Time

Similar to graph-gophers#407, but adds test cases.

Limit the number of concurrent list nodes processed

…tring argument

…trings

…tring argument

Update logic to always check for nil pointer returns

…lver itself panicks

The internal exec Subscribe method had code to deal with subscription resolver panicking
when being called. But when such handling happen, the error is attached to the request
object and it never checked later on.

This leads to some zero checks to fail when we try to extract the type from the resolver's
channel since this variable was never set. Doing this creates a second panic which is not
handled and make the application die.

To fix the issue, we now check if there is errors on the request object before continuing
with the rest of the check, if there is errors, it's because a panic occurs and we return
the response right away.

The previous value was hard-coded to 1 second. This is problematic for resolver that
takes more time than this to return a result.

When parsing the schema, it's not possible to pass a custom value for the subscription
resolver timeout.

Extracted from graph-gophers#317

Previously, any error returned by the Subscription resolver was immediately wrapped inside
its own `*QueryError` value even if the returned error was already a `*QueryError`.

Now, when receiving such types, we use it as-is without wrapping again.

…resolver-timeout

Added possibility to customize subscription resolver timeout value

…on-query-error

Allowed Subscription resolver to return `*QueryError` directly

# Conflicts:
#	subscription_test.go

…anic-in-resolver

Fixed `reflect.Value.Type on zero Value` panic when subscription resolver itself panics

Adding variables parameter for query validations.

Issue graph-gophers#299: unclear error message in case of multiline string argument

…face-inline-fragments

fix graph-gophers#241

… union types

Context is needed for tracing to access the current span, in order to
 add tags to it, or create child spans. As presently defined (without a
 context), this cannot be done: new spans could be created, but they
 would not be associated with the existing request trace.

OpenTracingTracer implements the new interface (it never implemented the
 old one). Via this 'extension interface', the tracer configured (or the
 default tracer) will be used as the validation tracer if:

 * The tracer implements the (optional) interface; and
 * A validation tracer isn't provided using the deprecated option

What this means is that the deprecated option is _preferred_ as an
 override. This allows users to migrate in a non-breaking, non-behaviour
 changing way, until such time as they intentionally remove the use of
 the deprecated option. For those who are currently using the default
 tracer, and not supplying a validation tracer, validation will be traced
 immediately with no change required to configuration options.

This allows to differentiate between an omitted value and a null value
in an input struct.

Add support for null vs missing input value

…ontext

Add context to validation tracing

DisableIntrospection should skip __typename

Fixed duplicated __typename in response (fixes graph-gophers#369)

- add tests for graphql.Time as reference implementation

…ds are actually visible

expose packer.Unmarshaler as decode.Unmarshaler to the public

Part of graph-gophers#434 and related to graph-gophers#116 this change adds a new package containing all
types used by graphql-go in representing the GraphQL specification. The names
used in this package should match the specification as closely as possible.

In order to have cohesion, all internal packages that use GraphQL types have
been changed to use this new package.

This change is large but mostly mechanical. I recommend starting by reading
through the `types` package to build familiarity. I'll call out places in the
code where I made decisions and what the tradeoffs were.

This additive function shouldn't break backward compatibility will allow those
who want access to the types to get at an AST version of the `types.Schema`

This was an error. When this field was renamed from schema.Field (to avoid
ambiguity) its name field changed to match query.Field (to Ident). This caused a
cascade of useless changes that will be rolled back in the next commit

add types package

Fix dir in readme

…test passed or failed

Add location fields to type definitions

errors.Errorf preserves original error similar to fmt.Error