Method FetchPullRequestDiff

coderd/externalauth/gitprovider/gitlab.go:226–278

(
	ctx context.Context,
	token string,
	ref PRRef,
)

}

func (g *gitlabProvider) FetchPullRequestDiff(
	ctx context.Context,
	token string,
	ref PRRef,
) (string, error) {
	pid := gitLabPID(ref.Owner, ref.Repo)

	// Make a direct HTTP request instead of using the library's
	// ShowMergeRequestRawDiffs, which reads the entire response
	// into memory before returning. We use io.LimitReader to
	// bound memory and reject diffs exceeding MaxDiffSize.
	rawURL := fmt.Sprintf("%sprojects/%s/merge_requests/%d/raw_diffs",
		g.client.BaseURL().String(), url.PathEscape(pid), ref.Number)
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
	if err != nil {
		return "", g.wrapError(err, "create raw diffs request")
	}
	if token != "" {
		req.Header.Set("Authorization", "Bearer "+token)
	}

	resp, err := g.client.HTTPClient().Do(req)
	if err != nil {
		return "", g.wrapError(err, "get merge request raw diffs")
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		if rlErr := checkRateLimitError(resp, g.clock, "RateLimit-Reset"); rlErr != nil {
			return "", rlErr
		}
		body, readErr := io.ReadAll(io.LimitReader(resp.Body, 8192))
		if readErr != nil {
			return "", g.wrapError(
				xerrors.Errorf("unexpected status %d", resp.StatusCode),
				"get merge request raw diffs",
			)
		}
		return "", g.wrapError(
			xerrors.Errorf("unexpected status %d: %s", resp.StatusCode, strings.TrimSpace(string(body))),
			"get merge request raw diffs",
		)
	}

	buf, err := io.ReadAll(io.LimitReader(resp.Body, MaxDiffSize+1))
	if err != nil {
		return "", g.wrapError(err, "read merge request raw diffs")
	}
	if len(buf) > MaxDiffSize {
		return "", ErrDiffTooLarge
	}
	return string(buf), nil
}

// compareResponse is the subset of GitLab's compare endpoint response
// that we need. We decode manually (instead of using the library) so