fix: pebble do not stop for default services start error

This reverts commit 1281c96
and reverts the hard-error behaviour introduced in
4098a71. Pebble should no longer,
at least not due to this commit, exit with non-zero error code if
waiting for the "change" (of default services start) to be ready
returns any errors.

internals/cli/cmd_enter_test.go

@@ -269,36 +269,3 @@ func (s *PebbleSuite) TestEnterSubCommandWaits(c *C) {
 
 	c.Check(svcStartTime.Before(subCmdExecTime), Equals, true)
 }
-
-// TestEnterDefaultServiceStartError tests whether default service
-// start errors are reported with non-zero exit codes. Note that,
-// for now this is only tested for
-//
-//	pebble enter --run <subcommand> [args..]
-//
-// Discussions about having this error reporting for “pebble run“
-// and similar scenarios can be found at:
-//   - https://github.com/canonical/pebble/pull/257#discussion_r1259070650
-//   - https://github.com/canonical/pebble/issues/167
-func (s *PebbleSuite) TestEnterDefaultServiceStartError(c *C) {
-	layerTemplate := dumbDedent(`
-		services:
-		  srv:
-		    override: replace
-		    command: unknownBinary123
-		    startup: enabled
-	`)
-	layerPath := filepath.Join(s.pebbleDir, "layers", "001-stat.yaml")
-	writeTemplate(layerPath, layerTemplate, nil)
-
-	cmd := []string{"pebble", "enter", "--run", "stop", "srv1"}
-	restore := fakeArgs(cmd...)
-	defer restore()
-
-	exitCode := cli.PebbleMain()
-	c.Check(exitCode, Equals, 1)
-	stderr := s.Stderr()
-	c.Check(stderr, Matches, "^(?s)cannot run pebble: error starting default services.*")
-	c.Check(stderr, Matches, "(?s).*Start service .* executable file not found in \\$PATH.*")
-	c.Check(s.Stdout(), Equals, "")
-}

internals/cli/cmd_run.go

@@ -245,7 +245,7 @@ out:
 			}
 		case chgErr := <-autoStartReady:
 			if chgErr != nil {
-				return fmt.Errorf("error starting default services: %w", chgErr)
+				logger.Noticef("Error starting default services: %v", chgErr)
 			}
 			notifyReady()
 		case <-stop: