Fix diff view provider using wrong ctx for cat

Summary:
We were using the ctx value for `cat` commands that was used when initializing the repo. However, if you change your cwd, you may get the "wrong" cwd when running cat, which fails. The right side of the comparison just uses the file URI, which is fine.

instead, we can just use the initial connection ctx for the repo, which we know will be valid for the repo in vscode.

Differential Revision: D55146168

fbshipit-source-id: d9678708540979c4375f5875825f088cac132005

addons/vscode/extension/DiffContentProvider.ts

@@ -155,9 +155,12 @@ export class SaplingDiffContentProvider implements vscode.TextDocumentContentPro
 
     const revset = revsetForComparison(data.comparison);
 
+    // Ensure we use a ctx appropriate for this repo. `this.ctx` may be an unrelated cwd.
+    const ctx = repo?.initialConnectionContext;
+
     // fall back to fetching from the repo
     const fetchedFileContent = await repo
-      .cat(this.ctx, fsPath, revset)
+      .cat(ctx, fsPath, revset)
       // An error during `cat` usually means the right side of the comparison was added since the left,
       // so `cat` claims `no such file` at that revset.
       // TODO: it would be more accurate to check that the error is due to this, and return null if not.

addons/vscode/extension/__tests__/DiffContentProvider.test.ts

@@ -71,6 +71,9 @@ function mockRepoAdded(): NonNullable<typeof activeRepo> {
     mockChangeHeadCommit(commit: CommitInfo) {
       savedOnChangeHeadCommit(commit);
     },
+    initialConnectionContext: {
+      cwd: '/path/to/repo',
+    },
   } as unknown as typeof activeRepo;
   activeReposCallback?.([nullthrows(activeRepo)]);
   return nullthrows(activeRepo);
@@ -111,7 +114,7 @@ describe('DiffContentProvider', () => {
 
     expect(content).toEqual(FILE1_CONTENT_HEAD);
     expect(repo.cat).toHaveBeenCalledTimes(1);
-    expect(repo.cat).toHaveBeenCalledWith(ctx, '/path/to/repo/file1.txt', '.');
+    expect(repo.cat).toHaveBeenCalledWith({cwd: '/path/to/repo'}, '/path/to/repo/file1.txt', '.');
     provider.dispose();
   });