github: add GraphQL schema and Flow types (#928)

Summary:
The included schema is forked from the one in `graphql/demo.js`.
Primitive types have been added, and the `parents` connection has been
added to commit objects per #920. (We do not include this in the demo
script because without prefetching it would take a long time to load.)

Test Plan:
Unit tests added; run `yarn unit`. Then run `yarn backend` and verify
that `node ./bin/generateGithubGraphqlFlowTypes.js` generates exactly
the same output as in the types file:

```
$ node ./bin/generateGithubGraphqlFlowTypes.js |
> diff -u - ./src/plugins/github/graphqlTypes.js
$ echo $?
0
```

Change the `graphqlTypes.js` file and verify that `yarn unit` fails.

As the build config has been changed, a `yarn test --full` is warranted.
It passes.

Finally, I have manually verified that the schema is consistent with the
documentation at <https://developer.github.com/v4/object/repository/>
and related pages.

wchargin-branch: github-schema-flow-types

config/paths.js

@@ -29,6 +29,9 @@ module.exports = {
   backendEntryPoints: {
     sourcecred: resolveApp("src/cli/main.js"),
     //
+    generateGithubGraphqlFlowTypes: resolveApp(
+      "src/plugins/github/bin/generateGraphqlFlowTypes.js"
+    ),
     fetchAndPrintGithubRepo: resolveApp(
       "src/plugins/github/bin/fetchAndPrintGithubRepo.js"
     ),

config/webpack.config.backend.js

@@ -21,6 +21,12 @@ module.exports = {
   bail: true,
   // Target Node instead of the browser.
   target: "node",
+  node: {
+    // Don't munge `__dirname` and `__filename`.
+    // https://github.com/webpack/webpack/issues/1599#issuecomment-186841345
+    __dirname: false,
+    __filename: false,
+  },
   entry: paths.backendEntryPoints,
   externals: [nodeExternals()],
   output: {

src/plugins/github/bin/generateGraphqlFlowTypes.js

@@ -0,0 +1,4 @@
+// @flow
+import generateGraphqlFlowTypes from "../generateGraphqlFlowTypes";
+
+process.stdout.write(generateGraphqlFlowTypes());

src/plugins/github/generateGraphqlFlowTypes.js

@@ -0,0 +1,14 @@
+// @flow
+
+import prettier from "prettier";
+
+import generateFlowTypes from "../../graphql/generateFlowTypes";
+import schema from "./schema";
+
+export default function generateGraphqlFlowTypes() {
+  const prettierOptions = {
+    ...{parser: "babylon"},
+    ...(prettier.resolveConfig.sync(__filename) || {}),
+  };
+  return generateFlowTypes(schema(), prettierOptions);
+}

src/plugins/github/graphqlTypes.js

@@ -0,0 +1,168 @@
+// @flow
+
+// Autogenerated file. Do not edit.
+
+export type Actor = Bot | Organization | User;
+
+export type Blob = {|
+  +__typename: "Blob",
+  +id: string,
+  +oid: GitObjectID,
+|};
+
+export type Bot = {|
+  +__typename: "Bot",
+  +id: string,
+  +login: String,
+  +url: URI,
+|};
+
+export type Commit = {|
+  +__typename: "Commit",
+  +author: null | {|
+    +date: null | GitTimestamp,
+    +user: null | User,
+  |},
+  +id: string,
+  +message: String,
+  +oid: GitObjectID,
+  +parents: $ReadOnlyArray<null | Commit>,
+  +url: URI,
+|};
+
+export type DateTime = string;
+
+export type GitObject = Blob | Commit | Tag | Tree;
+
+export type GitObjectID = string;
+
+export type GitTimestamp = string;
+
+export type Int = number;
+
+export type Issue = {|
+  +__typename: "Issue",
+  +author: null | Actor,
+  +body: String,
+  +comments: $ReadOnlyArray<null | IssueComment>,
+  +id: string,
+  +number: Int,
+  +reactions: $ReadOnlyArray<null | Reaction>,
+  +title: String,
+  +url: URI,
+|};
+
+export type IssueComment = {|
+  +__typename: "IssueComment",
+  +author: null | Actor,
+  +body: String,
+  +id: string,
+  +reactions: $ReadOnlyArray<null | Reaction>,
+  +url: URI,
+|};
+
+export type Organization = {|
+  +__typename: "Organization",
+  +id: string,
+  +login: String,
+  +url: URI,
+|};
+
+export type PullRequest = {|
+  +__typename: "PullRequest",
+  +additions: Int,
+  +author: null | Actor,
+  +body: String,
+  +comments: $ReadOnlyArray<null | IssueComment>,
+  +deletions: Int,
+  +id: string,
+  +mergeCommit: null | Commit,
+  +number: Int,
+  +reactions: $ReadOnlyArray<null | Reaction>,
+  +reviews: $ReadOnlyArray<null | PullRequestReview>,
+  +title: String,
+  +url: URI,
+|};
+
+export type PullRequestReview = {|
+  +__typename: "PullRequestReview",
+  +author: null | Actor,
+  +body: String,
+  +comments: $ReadOnlyArray<null | PullRequestReviewComment>,
+  +id: string,
+  +state: PullRequestReviewState,
+  +url: URI,
+|};
+
+export type PullRequestReviewComment = {|
+  +__typename: "PullRequestReviewComment",
+  +author: null | Actor,
+  +body: String,
+  +id: string,
+  +reactions: $ReadOnlyArray<null | Reaction>,
+  +url: URI,
+|};
+
+export type PullRequestReviewState =
+  | "APPROVED"
+  | "CHANGES_REQUESTED"
+  | "COMMENTED"
+  | "DISMISSED"
+  | "PENDING";
+
+export type Reaction = {|
+  +__typename: "Reaction",
+  +content: ReactionContent,
+  +id: string,
+  +user: null | User,
+|};
+
+export type ReactionContent =
+  | "CONFUSED"
+  | "HEART"
+  | "HOORAY"
+  | "LAUGH"
+  | "THUMBS_DOWN"
+  | "THUMBS_UP";
+
+export type Ref = {|
+  +__typename: "Ref",
+  +id: string,
+  +target: null | GitObject,
+|};
+
+export type Repository = {|
+  +__typename: "Repository",
+  +defaultBranchRef: null | Ref,
+  +id: string,
+  +issues: $ReadOnlyArray<null | Issue>,
+  +name: String,
+  +owner: null | RepositoryOwner,
+  +pullRequests: $ReadOnlyArray<null | PullRequest>,
+  +url: URI,
+|};
+
+export type RepositoryOwner = Organization | User;
+
+export type String = string;
+
+export type Tag = {|
+  +__typename: "Tag",
+  +id: string,
+  +oid: GitObjectID,
+|};
+
+export type Tree = {|
+  +__typename: "Tree",
+  +id: string,
+  +oid: GitObjectID,
+|};
+
+export type URI = string;
+
+export type User = {|
+  +__typename: "User",
+  +id: string,
+  +login: String,
+  +url: URI,
+|};

src/plugins/github/graphqlTypes.test.js

@@ -0,0 +1,18 @@
+// @flow
+
+import fs from "fs-extra";
+import path from "path";
+
+import generateGithubGraphqlFlowTypes from "./generateGraphqlFlowTypes";
+
+describe("plugins/github/graphqlTypes", () => {
+  it("is up to date", async () => {
+    const typesFilename = path.join(__dirname, "graphqlTypes.js");
+    const actual = (await fs.readFile(typesFilename)).toString();
+    const expected = generateGithubGraphqlFlowTypes();
+    // If this fails, run `yarn backend` and then invoke
+    //      node ./bin/generateGithubGraphqlFlowTypes.js
+    // saving the output to the types file listed above.
+    expect(actual).toEqual(expected);
+  });
+});

src/plugins/github/schema.js

@@ -0,0 +1,140 @@
+// @flow
+
+import * as Schema from "../../graphql/schema";
+
+export default function schema(): Schema.Schema {
+  const s = Schema;
+  const types = {
+    DateTime: s.scalar("string"),
+    GitObjectID: s.scalar("string"),
+    GitTimestamp: s.scalar("string"),
+    Int: s.scalar("number"),
+    String: s.scalar("string"),
+    URI: s.scalar("string"),
+    PullRequestReviewState: s.enum([
+      "PENDING",
+      "COMMENTED",
+      "APPROVED",
+      "CHANGES_REQUESTED",
+      "DISMISSED",
+    ]),
+    ReactionContent: s.enum([
+      "THUMBS_UP",
+      "THUMBS_DOWN",
+      "LAUGH",
+      "HOORAY",
+      "CONFUSED",
+      "HEART",
+    ]),
+    Repository: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      name: s.primitive(s.nonNull("String")),
+      owner: s.node("RepositoryOwner"),
+      issues: s.connection("Issue"),
+      pullRequests: s.connection("PullRequest"),
+      defaultBranchRef: s.node("Ref"),
+    }),
+    Issue: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      title: s.primitive(s.nonNull("String")),
+      body: s.primitive(s.nonNull("String")),
+      number: s.primitive(s.nonNull("Int")),
+      author: s.node("Actor"),
+      comments: s.connection("IssueComment"),
+      reactions: s.connection("Reaction"),
+    }),
+    PullRequest: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      title: s.primitive(s.nonNull("String")),
+      body: s.primitive(s.nonNull("String")),
+      number: s.primitive(s.nonNull("Int")),
+      mergeCommit: s.node("Commit"),
+      additions: s.primitive(s.nonNull("Int")),
+      deletions: s.primitive(s.nonNull("Int")),
+      author: s.node("Actor"),
+      comments: s.connection("IssueComment"), // yes, PRs have IssueComments
+      reviews: s.connection("PullRequestReview"),
+      reactions: s.connection("Reaction"),
+    }),
+    IssueComment: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      body: s.primitive(s.nonNull("String")),
+      author: s.node("Actor"),
+      reactions: s.connection("Reaction"),
+    }),
+    PullRequestReview: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      body: s.primitive(s.nonNull("String")),
+      author: s.node("Actor"),
+      state: s.primitive(s.nonNull("PullRequestReviewState")),
+      comments: s.connection("PullRequestReviewComment"),
+    }),
+    PullRequestReviewComment: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      body: s.primitive(s.nonNull("String")),
+      author: s.node("Actor"),
+      reactions: s.connection("Reaction"),
+    }),
+    Reaction: s.object({
+      id: s.id(),
+      content: s.primitive(s.nonNull("ReactionContent")),
+      user: s.node("User"),
+    }),
+    Ref: s.object({
+      id: s.id(),
+      // Unlike most node references, this is guaranteed non-null (but
+      // we have no way to express that).
+      target: s.node("GitObject"),
+    }),
+    GitObject: s.union(["Blob", "Commit", "Tag", "Tree"]),
+    Blob: s.object({
+      id: s.id(),
+      oid: s.primitive(s.nonNull("GitObjectID")),
+    }),
+    Commit: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      oid: s.primitive(s.nonNull("GitObjectID")),
+      message: s.primitive(s.nonNull("String")),
+      author: /* GitActor */ s.nested({
+        // The GitHub schema indicates that `date` can be null, but does
+        // not indicate when this might be the case.
+        date: s.primitive(s.nullable("GitTimestamp")),
+        user: s.node("User"),
+      }),
+      parents: s.connection("Commit"),
+    }),
+    Tag: s.object({
+      id: s.id(),
+      oid: s.primitive(s.nonNull("GitObjectID")),
+    }),
+    Tree: s.object({
+      id: s.id(),
+      oid: s.primitive(s.nonNull("GitObjectID")),
+    }),
+    Actor: s.union(["User", "Bot", "Organization"]), // actually an interface
+    RepositoryOwner: s.union(["User", "Organization"]), // actually an interface
+    User: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      login: s.primitive(s.nonNull("String")),
+    }),
+    Bot: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      login: s.primitive(s.nonNull("String")),
+    }),
+    Organization: s.object({
+      id: s.id(),
+      url: s.primitive(s.nonNull("URI")),
+      login: s.primitive(s.nonNull("String")),
+    }),
+  };
+  return s.schema(types);
+}

src/plugins/github/schema.test.js

@@ -0,0 +1,11 @@
+// @flow
+
+import schema from "./schema";
+
+describe("plugins/github/schema", () => {
+  describe("schema", () => {
+    it("creates a valid schema", () => {
+      expect(schema()).toEqual(expect.anything());
+    });
+  });
+});