Detect references in commit messages (#829)

Now that the GitHub plugin knows about commit messages (#828), we can
parse those commit messages to find references to other GitHub entities.

Fixed a minor typing mistake along the way.

Test plan:
Observe that a number of references have been detected among the commits
in the example GitHub repository. We mistakenly find references to
wchargin because we don't have a proper tokenizer. (#481)

Progress on #815.

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## [Unreleased]
+- Detect references in commit messages (#829)
 - Add commit authorship to the graph (#826)
 - Add `MentionsAuthor` edges to the graph (#808)
 <!-- Please add new entries to the _top_ of this section. -->

src/plugins/github/__snapshots__/createGraph.test.js.snap

@@ -1465,6 +1465,88 @@ Array [
         "dstIndex": 2,
         "srcIndex": 34,
       },
+      Object {
+        "address": Array [
+          "sourcecred",
+          "github",
+          "REFERENCES",
+          "4",
+          "sourcecred",
+          "git",
+          "COMMIT",
+          "0a223346b4e6dec0127b1e6aa892c4ee0424b66a",
+          "6",
+          "sourcecred",
+          "github",
+          "PULL",
+          "sourcecred",
+          "example-github",
+          "3",
+        ],
+        "dstIndex": 33,
+        "srcIndex": 0,
+      },
+      Object {
+        "address": Array [
+          "sourcecred",
+          "github",
+          "REFERENCES",
+          "4",
+          "sourcecred",
+          "git",
+          "COMMIT",
+          "6bd1b4c0b719c22c688a74863be07a699b7b9b34",
+          "5",
+          "sourcecred",
+          "github",
+          "USERLIKE",
+          "USER",
+          "wchargin",
+        ],
+        "dstIndex": 41,
+        "srcIndex": 1,
+      },
+      Object {
+        "address": Array [
+          "sourcecred",
+          "github",
+          "REFERENCES",
+          "4",
+          "sourcecred",
+          "git",
+          "COMMIT",
+          "6d5b3aa31ebb68a06ceb46bbd6cf49b6ccd6f5e6",
+          "6",
+          "sourcecred",
+          "github",
+          "PULL",
+          "sourcecred",
+          "example-github",
+          "5",
+        ],
+        "dstIndex": 34,
+        "srcIndex": 2,
+      },
+      Object {
+        "address": Array [
+          "sourcecred",
+          "github",
+          "REFERENCES",
+          "4",
+          "sourcecred",
+          "git",
+          "COMMIT",
+          "c430bd74455105f77215ece51945094ceeee6c86",
+          "5",
+          "sourcecred",
+          "github",
+          "USERLIKE",
+          "USER",
+          "wchargin",
+        ],
+        "dstIndex": 41,
+        "srcIndex": 3,
+      },
       Object {
         "address": Array [
           "sourcecred",

src/plugins/github/__snapshots__/relationalView.test.js.snap

@@ -351,5 +351,21 @@ Array [
     "from": "https://github.com/sourcecred/example-github/pull/3#issuecomment-369162222",
     "to": "https://github.com/sourcecred/example-github/issues/2",
   },
+  Object {
+    "from": "https://github.com/sourcecred/example-github/commit/0a223346b4e6dec0127b1e6aa892c4ee0424b66a",
+    "to": "https://github.com/sourcecred/example-github/pull/3",
+  },
+  Object {
+    "from": "https://github.com/sourcecred/example-github/commit/6d5b3aa31ebb68a06ceb46bbd6cf49b6ccd6f5e6",
+    "to": "https://github.com/sourcecred/example-github/pull/5",
+  },
+  Object {
+    "from": "https://github.com/sourcecred/example-github/commit/6bd1b4c0b719c22c688a74863be07a699b7b9b34",
+    "to": "https://github.com/wchargin",
+  },
+  Object {
+    "from": "https://github.com/sourcecred/example-github/commit/c430bd74455105f77215ece51945094ceeee6c86",
+    "to": "https://github.com/wchargin",
+  },
 ]
 `;

src/plugins/github/graphView.js

@@ -208,6 +208,7 @@ export class GraphView {
             GN.Prefix.pull,
             GN.Prefix.review,
             GN.Prefix.comment,
+            GitNode.Prefix.commit,
           ],
           [
             GN.Prefix.repo,

src/plugins/github/nodes.js

@@ -91,7 +91,8 @@ export type TextContentAddress =
   | IssueAddress
   | PullAddress
   | ReviewAddress
-  | CommentAddress;
+  | CommentAddress
+  | GitNode.CommitAddress;
 
 // Each of these types may be referred to by something
 // with text content.

src/plugins/github/relationalView.js

@@ -219,6 +219,7 @@ export class RelationalView {
     yield* this.pulls();
     yield* this.reviews();
     yield* this.comments();
+    yield* this.commits();
   }
 
   *parentEntities(): Iterator<ParentEntity> {
@@ -465,7 +466,8 @@ export class RelationalView {
     }
     for (const e of this.textContentEntities()) {
       const srcAddress = e.address();
-      for (const {ref, refType} of parseReferences(e.body())) {
+      const body = e instanceof Commit ? e.message() : e.body();
+      for (const {ref, refType} of parseReferences(body)) {
         const refAddress = refToAddress.get(ref);
         if (refAddress != null) {
           switch (refType) {
@@ -544,6 +546,9 @@ export class RelationalView {
           case "COMMENT":
             entity = this.comment(address);
             break;
+          case "COMMIT":
+            entity = this.commit(address);
+            break;
           default:
             throw new Error(
               `Unexpected referrer address type: ${(address.type: empty)}`
@@ -661,7 +666,7 @@ export class Repo extends _Entity<RepoEntry> {
       yield assertExists(pull, address);
     }
   }
-  referencedBy(): Iterator<ReferentEntity> {
+  referencedBy(): Iterator<TextContentEntity> {
     return this._view._referencedBy(this);
   }
 }
@@ -874,6 +879,9 @@ export class Commit extends _Entity<CommitEntry> {
   message(): string {
     return this._entry.message;
   }
+  references(): Iterator<ReferentEntity> {
+    return this._view._references(this);
+  }
 }
 
 type UserlikeEntry = {|
@@ -948,7 +956,7 @@ export function match<T>(handlers: MatchHandlers<T>, x: Entity): T {
 
 export type Entity = Repo | Issue | Pull | Review | Comment | Commit | Userlike;
 export type AuthoredEntity = Issue | Pull | Review | Comment | Commit;
-export type TextContentEntity = Issue | Pull | Review | Comment;
+export type TextContentEntity = Issue | Pull | Review | Comment | Commit;
 export type ParentEntity = Repo | Issue | Pull | Review;
 export type ChildEntity = Issue | Pull | Review | Comment;
 export type ReferentEntity = Repo | Issue | Pull | Review | Comment | Userlike;