Cred explorer: display commit short hash + summary (#879)

This modifies how commits are displayed in the cred explorer. Rather
than printing the full hash, we now print a short hash followed by the
summary.

Test plan:
Snapshot is updated, also I tested it by running SourceCred on a real
repository.

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## [Unreleased]
+- Display short hash + summary for commits (#879)
 - Hyperlink to GitHub entities (#860)
 - Add GitHub reactions to the graph (#846)
 - Detect references to commits (#833)

src/plugins/git/__snapshots__/render.test.js.snap

@@ -1,3 +1,3 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`plugins/git/render commit snapshots as expected 1`] = `"commit 3715ddfb8d4c4fd2a6f6af75488c82f84c92ec2f"`;
+exports[`plugins/git/render commit snapshots as expected 1`] = `"3715ddf: This is an example commit"`;

src/plugins/git/pluginAdapter.js

@@ -9,6 +9,7 @@ import * as E from "./edges";
 import {description} from "./render";
 import type {Assets} from "../../app/assets";
 import type {Repo} from "../../core/repo";
+import type {Repository} from "./types";
 
 export class StaticPluginAdapter implements IStaticPluginAdapter {
   name() {
@@ -42,23 +43,38 @@ export class StaticPluginAdapter implements IStaticPluginAdapter {
     ];
   }
   async load(assets: Assets, repo: Repo): Promise<IDynamicPluginAdapter> {
-    const url = assets.resolve(
-      `/api/v1/data/data/${repo.owner}/${repo.name}/git/graph.json`
-    );
-    const response = await fetch(url);
-    if (!response.ok) {
-      return Promise.reject(response);
+    const baseUrl = `/api/v1/data/data/${repo.owner}/${repo.name}/git/`;
+    async function loadGraph() {
+      const url = assets.resolve(baseUrl + "graph.json");
+      const response = await fetch(url);
+      if (!response.ok) {
+        return Promise.reject(response);
+      }
+      const json = await response.json();
+      return Graph.fromJSON(json);
     }
-    const json = await response.json();
-    const graph = Graph.fromJSON(json);
-    return new DynamicPluginAdapter(graph);
+    async function loadRepository(): Promise<Repository> {
+      const url = assets.resolve(baseUrl + "repository.json");
+      const response = await fetch(url);
+      if (!response.ok) {
+        return Promise.reject(response);
+      }
+      return await response.json();
+    }
+    const [graph, repository] = await Promise.all([
+      loadGraph(),
+      loadRepository(),
+    ]);
+    return new DynamicPluginAdapter(graph, repository);
   }
 }
 
 class DynamicPluginAdapter implements IDynamicPluginAdapter {
   +_graph: Graph;
-  constructor(graph: Graph) {
+  +_repository: Repository;
+  constructor(graph: Graph, repository: Repository) {
     this._graph = graph;
+    this._repository = repository;
   }
   graph() {
     return this._graph;
@@ -67,7 +83,7 @@ class DynamicPluginAdapter implements IDynamicPluginAdapter {
     // This cast is unsound, and might throw at runtime, but won't have
     // silent failures or cause problems down the road.
     const address = N.fromRaw((node: any));
-    return description(address);
+    return description(address, this._repository);
   }
   static() {
     return new StaticPluginAdapter();

src/plugins/git/render.js

@@ -1,19 +1,23 @@
 // @flow
 
 import * as N from "./nodes";
+import type {Repository} from "./types";
 
-export function description(address: N.StructuredAddress) {
+export function description(
+  address: N.StructuredAddress,
+  repository: Repository
+) {
   switch (address.type) {
-    case "COMMIT":
-      return `commit ${address.hash}`;
-    case "TREE":
-      return `tree ${address.hash}`;
-    case "BLOB":
-      return `blob ${address.hash}`;
-    case "TREE_ENTRY":
-      return `entry ${JSON.stringify(address.name)} in tree ${
-        address.treeHash
-      }`;
+    case "COMMIT": {
+      const hash = address.hash;
+      const commit = repository.commits[hash];
+      if (commit == null) {
+        console.error(`Unable to find data for commit ${hash}`);
+        return hash;
+      }
+      const {shortHash, summary} = commit;
+      return `${shortHash}: ${summary}`;
+    }
     default:
       throw new Error(`unknown type: ${(address.type: empty)}`);
   }

src/plugins/git/render.test.js

@@ -2,15 +2,35 @@
 
 import * as GN from "./nodes";
 import {description} from "./render";
+import type {Repository} from "./types";
 
 describe("plugins/git/render", () => {
-  const examples = {
-    commit: (): GN.CommitAddress => ({
-      type: GN.COMMIT_TYPE,
-      hash: "3715ddfb8d4c4fd2a6f6af75488c82f84c92ec2f",
-    }),
-  };
+  const exampleHash = "3715ddfb8d4c4fd2a6f6af75488c82f84c92ec2f";
+  const exampleCommit: GN.CommitAddress = Object.freeze({
+    type: GN.COMMIT_TYPE,
+    hash: exampleHash,
+  });
+  const exampleRepository: Repository = Object.freeze({
+    commits: {
+      [exampleHash]: {
+        hash: exampleHash,
+        shortHash: exampleHash.slice(0, 7),
+        summary: "This is an example commit",
+        parentHashes: [],
+      },
+    },
+  });
+
   it("commit snapshots as expected", () => {
-    expect(description(examples.commit())).toMatchSnapshot();
+    expect(description(exampleCommit, exampleRepository)).toMatchSnapshot();
+  });
+  it("logs an error for a commit not in the repository", () => {
+    const badCommit = {type: GN.COMMIT_TYPE, hash: "1234"};
+    // $ExpectFlowError
+    console.error = jest.fn();
+    expect(description(badCommit, exampleRepository)).toBe("1234");
+    expect(console.error).toHaveBeenCalledWith(
+      "Unable to find data for commit 1234"
+    );
   });
 });