Fixes #162, 'Couldn't find commit' error notification

Author: Rachel Macfarlane

src/common/repository.ts

@@ -288,6 +288,15 @@ export class Repository {
 		}
 	}
 
+	async checkCommitExists(commit: string): Promise<boolean> {
+		try {
+			const result = await this.run(['show', '-q', commit]);
+			return result.stdout.trim().length !== 0;
+		} catch (e) {
+			return false;
+		}
+	}
+
 	async getFileObjectId(commit: string, path: string): Promise<string> {
 		try {
 			const args = ['rev-parse', `${commit}:${path}`];

src/view/gitContentProvider.ts

@@ -23,14 +23,21 @@ export class GitContentProvider implements vscode.TextDocumentContentProvider {
 			return '';
 		}
 
-		let ret = await this.repository.show(`${commit}:${path}`);
-
-		if (!ret) {
-			vscode.window.showErrorMessage(`We couldn't find commit ${commit} locally. You may want to sync the branch with remote. Sometimes commits can disappear after a force-push`);
-			ret = await this._fallback(uri);
+		let content = await this.repository.show(`${commit}:${path}`);
+
+		if (!content) {
+			content = await this._fallback(uri);
+			if (!content) {
+				// Content does not exist for the base or modified file for a file deletion or addition.
+				// Manually check if the commit exists before notifying the user.
+				const commitExistsLocally = await this.repository.checkCommitExists(commit);
+				if (!commitExistsLocally) {
+					vscode.window.showErrorMessage(`We couldn't find commit ${commit} locally. You may want to sync the branch with remote. Sometimes commits can disappear after a force-push`);
+				}
+			}
 		}
 
-		return ret || '';
+		return content || '';
 	}
 
 	registerTextDocumentContentFallback(provider: (uri: vscode.Uri) => Promise<string>) {