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Merged
Mpdreamz merged 1 commit into from
May 11, 2026
Merged

fix(generator): error on unknown command flags with Levenshtein suggestions #53

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111 changes: 107 additions & 4 deletions src/Nullean.Argh.Generator/CliParserGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3823,6 +3823,8 @@ private static void EmitFuzzyDispatchDefault(
sb.AppendLine("\t\t\t\tif (__matches.Count == 0)");
sb.AppendLine("\t\t\t\t{");
sb.AppendLine($"\t\t\t\t\tConsole.Error.WriteLine($\"Error: unknown {kind} '{{__tok}}'.\");");
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\t\tConsole.Error.WriteLine($\"Run '{{__app}} {nsHelp}' for usage.\");");
sb.AppendLine("\t\t\t\t}");
sb.AppendLine("\t\t\t\telse if (__matches.Count == 1)");
sb.AppendLine("\t\t\t\t{");
Expand Down Expand Up @@ -6484,6 +6486,85 @@ private static void EmitValidationChecks(

private static string EscapeVerbatimString(string s) => s.Replace("\"", "\"\"");

private static void EmitCommandRunnerFuzzyFailHelper(
StringBuilder sb,
CommandModel cmd,
string? flagHelpStdErrMethodName,
string? parseFailureRunHint)
{
var flagParams = cmd.Parameters
.Where(static p => IsEmittedFlagLike(p.Kind))
.ToList();

if (flagParams.Count > 0)
{
sb.Append("\t\t\tvar __flagFuzzyCands = new string[] { ");
var sortedNames = flagParams
.Select(static p => p.CliLongName)
.Distinct(StringComparer.OrdinalIgnoreCase)
.OrderBy(static x => x, StringComparer.OrdinalIgnoreCase)
.ToList();
for (var i = 0; i < sortedNames.Count; i++)
{
if (i > 0)
sb.Append(", ");
sb.Append('"').Append(Escape(sortedNames[i])).Append('"');
}
sb.AppendLine(" };");
}

sb.AppendLine("\t\t\tint FailUnknownLongOption(string flagName)");
sb.AppendLine("\t\t\t{");
if (flagParams.Count > 0)
{
sb.AppendLine($"\t\t\t\tvar __matches = FuzzyMatch.FindClosest(flagName, __flagFuzzyCands, {FuzzyMaxDistance});");
sb.AppendLine("\t\t\t\tif (__matches.Count == 0)");
sb.AppendLine("\t\t\t\t{");
}
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine($\"Error: unknown option '--{flagName}'.\");");
if (parseFailureRunHint is not null)
{
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\t\tConsole.Error.WriteLine(\"{Escape(parseFailureRunHint)}\");");
}
sb.AppendLine("\t\t\t\t\treturn 2;");
if (flagParams.Count > 0)
{
sb.AppendLine("\t\t\t\t}");
sb.AppendLine("\t\t\t\tif (__matches.Count == 1)");
sb.AppendLine("\t\t\t\t{");
sb.AppendLine("\t\t\t\t\tvar __m = __matches[0];");
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine($\"Error: unknown option '--{flagName}'. Did you mean '--{__m}'?\");");
if (flagHelpStdErrMethodName is not null)
{
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\t\t{flagHelpStdErrMethodName}(__m);");
}
if (parseFailureRunHint is not null)
{
sb.AppendLine("\t\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\t\tConsole.Error.WriteLine(\"{Escape(parseFailureRunHint)}\");");
}
sb.AppendLine("\t\t\t\t\treturn 2;");
sb.AppendLine("\t\t\t\t}");
sb.AppendLine("\t\t\t\tConsole.Error.WriteLine($\"Error: unknown option '--{flagName}'. Did you mean one of these?\");");
sb.AppendLine("\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine("\t\t\t\tforeach (var __m in __matches)");
sb.AppendLine("\t\t\t\t{");
if (flagHelpStdErrMethodName is not null)
sb.AppendLine($"\t\t\t\t\t{flagHelpStdErrMethodName}(__m);");
sb.AppendLine("\t\t\t\t}");
if (parseFailureRunHint is not null)
{
sb.AppendLine("\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\tConsole.Error.WriteLine(\"{Escape(parseFailureRunHint)}\");");
}
sb.AppendLine("\t\t\t\treturn 2;");
}
sb.AppendLine("\t\t\t}");
sb.AppendLine();
}

private static void EmitCommandRunner(
StringBuilder sb,
CommandModel cmd,
Expand Down Expand Up @@ -6557,9 +6638,11 @@ private static void EmitCommandRunner(
sb.AppendLine("\t\t\tvar positionals = new List<string>();");
EmitBoolSwitchNames(sb, cmd);
EmitCanonFlagNameMethod(sb, cmd);
EmitShortFlagMethods(sb, cmd, multiFlagsAvailable: anyRepeatedCollection);
if (emitDtoTryParse)
EmitKnownNonBoolFlagNames(sb, cmd);
EmitShortFlagMethods(sb, cmd, multiFlagsAvailable: anyRepeatedCollection,
parseFailureRunHint: emitDtoTryParse ? null : parseFailureRunHint);
EmitKnownNonBoolFlagNames(sb, cmd);
if (!emitDtoTryParse)
EmitCommandRunnerFuzzyFailHelper(sb, cmd, flagHelpStdErrMethodName, parseFailureRunHint);
sb.AppendLine("\t\t\tfor (var i = 0; i < args.Length;)");
sb.AppendLine("\t\t\t{");
sb.AppendLine("\t\t\t\tvar a = args[i];");
Expand All @@ -6578,6 +6661,11 @@ private static void EmitCommandRunner(
sb.AppendLine($"\t\t\t\t\t\t\t{failureExit};");
sb.AppendLine("\t\t\t\t\t\t}");
}
else if (!emitDtoTryParse)
{
sb.AppendLine("\t\t\t\t\t\tif (!IsBoolSwitchName(flagName) && !IsKnownNonBoolFlagName(flagName))");
sb.AppendLine("\t\t\t\t\t\t\treturn FailUnknownLongOption(flagName);");
}
if (anyRepeatedCollection)
{
sb.AppendLine("\t\t\t\t\t\tSetFlag(flagName, flagValue);");
Expand Down Expand Up @@ -6621,6 +6709,11 @@ private static void EmitCommandRunner(
sb.AppendLine("\t\t\t\t\t\t\t}");
}
}
else
{
sb.AppendLine("\t\t\t\t\t\t\tif (!IsKnownNonBoolFlagName(flagName))");
sb.AppendLine("\t\t\t\t\t\t\t\treturn FailUnknownLongOption(flagName);");
}
sb.AppendLine("\t\t\t\t\t\t\tif (i + 1 >= args.Length)");
sb.AppendLine("\t\t\t\t\t\t\t{");
sb.AppendLine("\t\t\t\t\t\t\t\tConsole.Error.WriteLine($\"Error: missing value for flag --{flagName}.\");");
Expand Down Expand Up @@ -7313,7 +7406,7 @@ private static void EmitCanonFlagNameMethod(StringBuilder sb, CommandModel cmd)
sb.AppendLine("\t\t\t};");
}

private static void EmitShortFlagMethods(StringBuilder sb, CommandModel cmd, bool multiFlagsAvailable = true)
private static void EmitShortFlagMethods(StringBuilder sb, CommandModel cmd, bool multiFlagsAvailable = true, string? parseFailureRunHint = null)
{
var shortCases = new List<(char c, string Primary, bool IsBool, bool IsRepeatableCollection)>();
foreach (var p in cmd.Parameters)
Expand All @@ -7332,6 +7425,11 @@ private static void EmitShortFlagMethods(StringBuilder sb, CommandModel cmd, boo
sb.AppendLine("\t\t\tbool TryApplyShortFlag(char c, string val)");
sb.AppendLine("\t\t\t{");
sb.AppendLine("\t\t\t\tConsole.Error.WriteLine($\"Error: unknown short option '-{c}'.\");");
if (parseFailureRunHint is not null)
{
sb.AppendLine("\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\tConsole.Error.WriteLine(\"{Escape(parseFailureRunHint)}\");");
}
sb.AppendLine("\t\t\t\treturn false;");
sb.AppendLine("\t\t\t}");
sb.AppendLine("\t\t\tbool IsShortBoolChar(char c) => false;");
Expand Down Expand Up @@ -7361,6 +7459,11 @@ private static void EmitShortFlagMethods(StringBuilder sb, CommandModel cmd, boo

sb.AppendLine("\t\t\t\t\tdefault:");
sb.AppendLine("\t\t\t\t\t\tConsole.Error.WriteLine($\"Error: unknown short option '-{c}'.\");");
if (parseFailureRunHint is not null)
{
sb.AppendLine("\t\t\t\t\t\tConsole.Error.WriteLine();");
sb.AppendLine($"\t\t\t\t\t\tConsole.Error.WriteLine(\"{Escape(parseFailureRunHint)}\");");
}
sb.AppendLine("\t\t\t\t\t\treturn false;");
sb.AppendLine("\t\t\t\t}");
sb.AppendLine("\t\t\t}");
Expand Down
83 changes: 83 additions & 0 deletions tests/Nullean.Argh.IntegrationTests/ParseErrors/ParseErrorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,89 @@ public void Global_flag_typo_suggests_did_you_mean_and_prints_flag_help()
err.Should().Contain("--severity <enum>");
}

[Fact]
public void Command_flag_typo_returns_exit_2()
{
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"hello", "--nme", "world");
result.ExitCode.Should().Be(2);
}

[Fact]
public void Command_flag_typo_suggests_did_you_mean_and_prints_flag_help()
{
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"hello", "--nme", "world");
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown option '--nme'. Did you mean '--name'?");
err.Should().Contain("--name <string>");
err.Should().Contain($"Run '{CliHostPaths.CliHostAssemblyName} hello --help' for usage.");
ConsoleOutput.Normalize(CliHostRunner.StdoutText(result)).Should().BeEmpty();
}

[Fact]
public void Command_flag_equals_syntax_typo_returns_exit_2()
{
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"hello", "--nme=world");
result.ExitCode.Should().Be(2);
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown option '--nme'. Did you mean '--name'?");
}

[Fact]
public void Command_completely_unknown_flag_returns_exit_2_with_run_hint()
{
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"hello", "--zzz", "x");
result.ExitCode.Should().Be(2);
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown option '--zzz'.");
err.Should().Contain($"Run '{CliHostPaths.CliHostAssemblyName} hello --help' for usage.");
}

[Fact]
public void Command_unknown_short_flag_returns_exit_2_with_run_hint()
{
// enum-cmd has -n and -c; passing -z is unknown
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"enum-cmd", "-z", "val");
result.ExitCode.Should().Be(2);
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown short option '-z'.");
err.Should().Contain($"Run '{CliHostPaths.CliHostAssemblyName} enum-cmd --help' for usage.");
}

[Fact]
public void Unknown_namespace_command_no_match_prints_ns_help_hint()
{
// 'storage' namespace has 'list' and 'blob' — 'zzz' has no close match
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"storage", "zzz");
result.ExitCode.Should().Be(2);
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown command or namespace 'zzz'.");
err.Should().Contain($"Run '{CliHostPaths.CliHostAssemblyName} storage --help' for usage.");
}

[Fact]
public void Unknown_root_command_no_match_prints_root_help_hint()
{
var result = CliHostRunner.Run(
new Dictionary<string, string>(StringComparer.Ordinal) { ["NO_COLOR"] = "1" },
"zzz-completely-unknown");
result.ExitCode.Should().Be(2);
var err = ConsoleOutput.Normalize(CliHostRunner.StderrText(result));
err.Should().Contain("Error: unknown command or namespace 'zzz-completely-unknown'.");
err.Should().Contain($"Run '{CliHostPaths.CliHostAssemblyName} --help' for usage.");
}

[Fact]
public void Non_nullable_global_option_property_with_default_is_not_required()
{
Expand Down
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