Copilot plugin will inflate .git folders

[st0rm23]

• Copilot Chat Extension Version:1.346.0
• VS Code Version: 1.102.1
• OS Version: ubuntu 20.04
• Feature (e.g. agent/edit/ask mode): agent
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): N.A
• Logs:

Problem:
We have a large codebase contributed by 1k+ engineer. Most of time, I just track the master branch. However, when I use vscode with copilot, it will inflate .git folder into a huge size. It is because vscode copilot will trigger git fetch --dry-run which is not neccessary. This fetch will download all objects of all refs into .git.

Steps to Reproduce:

1. Clone a repo like https://github.com/git/git
2. use du .git to get git/.git folder size
3. Start vscode with copilot enabled on git folder
4. use ps -aux | grep git you would see a command git -c credential.interactive=never fetch --dry-run is executing.
5. wait 2~3 minutes, use du .git to get git/.git folder size again, you would see the .git folder size increased.

Root cause:
git fetch --dry-run is not trivial but fetching objects into .git folder. This will inflate .git folder. The code piece lies in https://github.com/microsoft/vscode-copilot-chat/blob/main/src/platform/remoteCodeSearch/node/codeSearchRepoTracker.ts#L590, which is using git fetch to get ssh config. This is not the right way, please fix this bug and change to another simple way to get ssh config.

	private async getGithubRemoteFromSshConfig(repo: RepoContext): Promise<ResolvedRepoRemoteInfo | undefined> {
		if (repo.rootUri.scheme !== Schemas.file) {
			return;
		}

		try {
			const execAsync = promisify(exec);
			const { stdout, stderr } = await execAsync('git -c credential.interactive=never fetch --dry-run', {
				cwd: repo.rootUri.fsPath,
				env: {
					GIT_SSH_COMMAND: 'ssh -v -o BatchMode=yes'
				}
			});

			const output = stdout + '\n' + stderr;

			const authMatch = output.match(/^Authenticated to ([^\s]+)\s/m);
			const fromMatch = output.match(/^From ([^:]+):([^/]+)\/([^\s]+)$/m);

			if (authMatch && fromMatch) {
				const authenticatedTo = authMatch[1];
				const owner = fromMatch[2];
				const repo = fromMatch[3].replace(/\.git$/, '');
				const remoteUrl = `ssh://${authenticatedTo}/${owner}/${repo}`;

				const githubRepoId = getGithubRepoIdFromFetchUrl(remoteUrl);
				if (githubRepoId) {
					return {
						repoId: githubRepoId,
						fetchUrl: remoteUrl
					};
				}
			}
			return undefined;
		} catch (e) {
			return undefined;
		}
	}

[vs-code-engineering]

Thanks for creating this issue! It looks like you may be using an old version of VS Code, the latest stable release is 1.102.2. Please try upgrading to the latest version and checking whether this issue remains.

Happy Coding!