Avoid throw in SelfUpdaters.

[TingluoHuang]

https://github.com/github/actions-runtime/issues/5424

[Copilot]

Pull request overview

Adjusts the runner self-update flows to avoid propagating exceptions during self-update failures (per actions-runtime issue #5424), and instead surface failures via logging/terminal output while allowing the listener to continue running.

Changes:

• Stop rethrowing exceptions from SelfUpdate in both legacy and V2 self-updaters.
• Add error logging (Trace.Error) and user-visible terminal error output when self-update fails.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/Runner.Listener/SelfUpdater.cs	Swallows self-update exceptions and logs/shows an error instead of throwing.
src/Runner.Listener/SelfUpdaterV2.cs	Same change for the newer self-update flow (message contains package metadata directly).

Comments suppressed due to low confidence (2)

src/Runner.Listener/SelfUpdater.cs:126

• This changes the contract of SelfUpdate from throwing on failures (e.g., download/validation errors) to swallowing exceptions. The existing L0 tests currently assert exceptions are thrown (e.g., TestSelfUpdateAsync_DownloadRunner / TestSelfUpdateAsync_ValidateHash); they will need to be updated to assert the new false return behavior (and/or verify error output).

            catch (Exception ex)
            {
                Trace.Error(ex);
                _terminal.WriteError($"Runner update failed: {ex.Message}");
                _updateTrace.Enqueue(ex.ToString());
            }

src/Runner.Listener/SelfUpdaterV2.cs:126

• This changes the contract of SelfUpdate from throwing on failures (e.g., download/validation errors) to swallowing exceptions. The existing L0 tests for SelfUpdaterV2 currently assert exceptions are thrown; they should be updated to reflect the new false return behavior (and/or verify error output).

            catch (Exception ex)
            {
                Trace.Error(ex);
                _terminal.WriteError($"Runner update failed: {ex.Message}");
                _updateTrace.Enqueue(ex.ToString());
            }