Decouple error reporting from logging

The Fail callback was routing errors through the slog logger, which meant:
- Errors appeared as structured log messages (with timestamp and level)
- --log-level never silently swallowed errors
- --log-format json wrapped errors in JSON

Errors are now always printed directly to stderr as "Error: <message>",
independent of log configuration.

Default log level changed from "info" to "never"; server start-dev
continues to default to "warn" via its existing ChangedFromDefault
override. Users can still opt in with --log-level on any command.

Two deprecation warnings (namespace arg, env command args) converted
from logger calls to direct stderr writes so they remain visible
regardless of log level.

Author: dandavison

cliext/flags.gen.go

@@ -38,8 +38,8 @@ func (v *CommonOptions) BuildFlags(f *pflag.FlagSet) {
 	f.StringVar(&v.Profile, "profile", "", "Profile to use for config file. EXPERIMENTAL.")
 	f.BoolVar(&v.DisableConfigFile, "disable-config-file", false, "If set, disables loading environment config from config file. EXPERIMENTAL.")
 	f.BoolVar(&v.DisableConfigEnv, "disable-config-env", false, "If set, disables loading environment config from environment variables. EXPERIMENTAL.")
-	v.LogLevel = NewFlagStringEnum([]string{"debug", "info", "warn", "error", "never"}, "info")
-	f.Var(&v.LogLevel, "log-level", "Log level. Default is \"info\" for most commands and \"warn\" for \"server start-dev\". Accepted values: debug, info, warn, error, never.")
+	v.LogLevel = NewFlagStringEnum([]string{"debug", "info", "warn", "error", "never"}, "never")
+	f.Var(&v.LogLevel, "log-level", "Log level. Default is \"never\" for most commands and \"warn\" for \"server start-dev\". Accepted values: debug, info, warn, error, never.")
 	v.LogFormat = NewFlagStringEnum([]string{"text", "json", "pretty"}, "text")
 	f.Var(&v.LogFormat, "log-format", "Log format. Accepted values: text, json.")
 	v.Output = NewFlagStringEnum([]string{"text", "json", "jsonl", "none"}, "text")

cliext/option-sets.yaml

@@ -51,8 +51,8 @@ option-sets:
           - never
         description: |
           Log level.
-          Default is "info" for most commands and "warn" for "server start-dev".
-        default: info
+          Default is "never" for most commands and "warn" for "server start-dev".
+        default: never
       - name: log-format
         type: string-enum
         description: Log format.

internal/temporalcli/commands.env.go

@@ -13,7 +13,7 @@ import (
 
 func (c *TemporalEnvCommand) envNameAndKey(cctx *CommandContext, args []string, keyFlag string) (string, string, error) {
 	if len(args) > 0 {
-		cctx.Logger.Warn("Arguments to env commands are deprecated; please use --env and --key (or -k) instead")
+		fmt.Fprintln(cctx.Options.Stderr, "Warning: Arguments to env commands are deprecated; please use --env and --key (or -k) instead")
 
 		if c.Parent.Env != "default" || keyFlag != "" {
 			return "", "", fmt.Errorf("cannot specify both an argument and flags; please use flags instead")

internal/temporalcli/commands.go

@@ -143,11 +143,7 @@ func (c *CommandContext) preprocessOptions() error {
 			if c.Err() != nil {
 				err = fmt.Errorf("program interrupted")
 			}
-			if c.Logger != nil {
-				c.Logger.Error(err.Error())
-			} else {
-				fmt.Fprintln(os.Stderr, err)
-			}
+			fmt.Fprintf(c.Options.Stderr, "Error: %v\n", err)
 			os.Exit(1)
 		}
 	}

internal/temporalcli/commands.operator_namespace.go

@@ -19,7 +19,7 @@ func (c *TemporalOperatorCommand) getNSFromFlagOrArg0(cctx *CommandContext, args
 	}
 
 	if len(args) > 0 {
-		cctx.Logger.Warn("Passing the namespace as an argument is now deprecated; please switch to using -n instead")
+		fmt.Fprintln(cctx.Options.Stderr, "Warning: Passing the namespace as an argument is now deprecated; please switch to using -n instead")
 		return args[0], nil
 	}
 	return c.Namespace, nil

internal/temporalcli/commands.workflow_exec.go

@@ -94,7 +94,7 @@ func (c *TemporalWorkflowExecuteCommand) run(cctx *CommandContext, args []string
 	// Log print failure and return workflow failure if workflow failed
 	if closeEvent.EventType != enums.EVENT_TYPE_WORKFLOW_EXECUTION_COMPLETED {
 		if err != nil {
-			cctx.Logger.Error("Workflow failed, and printing the output also failed", "error", err)
+			fmt.Fprintf(cctx.Options.Stderr, "Warning: printing workflow output failed: %v\n", err)
 		}
 		err = fmt.Errorf("workflow failed")
 	}

internal/temporalcli/commands.workflow_view.go

@@ -560,7 +560,7 @@ func (c *TemporalWorkflowResultCommand) run(cctx *CommandContext, _ []string) er
 	// Log print failure and return workflow failure if workflow failed
 	if closeEvent.EventType != enums.EVENT_TYPE_WORKFLOW_EXECUTION_COMPLETED {
 		if err != nil {
-			cctx.Logger.Error("Workflow failed, and printing the output also failed", "error", err)
+			fmt.Fprintf(cctx.Options.Stderr, "Warning: printing workflow output failed: %v\n", err)
 		}
 		err = fmt.Errorf("workflow failed")
 	}