report usage errors as JSON on stderr when --json is given, as the document asks (3.0.48)

@@ -1 +1 @@1-3.0.471+3.0.48

@@ -124,9 +124,7 @@124124 			return cmd_man(rest)125125 		}126126 		else {127-			eprintln('  koh: unknown command "${argv[1]}"')128-			eprintln('  run "koh --help" for the command list')129-			return 2127+			return usage_error('unknown command "${argv[1]}" — run "koh --help" for the command list')130128 		}131129 	}132130 }

@@ -9,6 +9,7 @@99 module cli1010 1111 import json12+import os1213 import src.fmt1314 1415 pub fn ok(message string) {@@ -36,8 +37,14 @@3637 	return 13738 }3839 40+// usage_error reports a mistake in the command line itself. It can happen41+// before the options are parsed, so `--json` is looked for on the raw line.3942 pub fn usage_error(message string) int {40-	eprintln('  ${fmt.red(fmt.glyph_fail)} ${message}')43+	if '--json' in os.args {44+		fail_json(message)45+	} else {46+		eprintln('  ${fmt.red(fmt.glyph_fail)} ${message}')47+	}4148 	return 24249 }4350 

@@ -94,6 +94,14 @@9494 	assert run(dir, 'init').code == 19595 	assert run(dir, 'unknown-command').code == 29696 	assert run(dir, 'unknown-command').err.contains('unknown command')97+	// An agent asking for JSON gets JSON for a usage mistake too, exit 2.98+	for args in [['unknown-command', '--json'], ['save', '--json'],99+		['save', 'x', '--nope', '--json']] {100+		r2 := run(dir, ...args)101+		assert r2.code == 2102+		assert r2.out == ''103+		assert r2.err.starts_with('{"error":'), r2.err104+	}97105 }98106 99107 fn test_save_checkpoint_and_status() {

@@ -1,6 +1,6 @@11 Module {22 	name: 'koh3'3-	version: '3.0.47'3+	version: '3.0.48'44 	description: 'One SQLite file per repo, one line of history.'55 	license: 'MIT'66 }