M0.9: --help wins over an earlier bad option (#1155)

Review: `mcp --bogus --help` stopped at --bogus with exit 2. The parser
now keeps the first bad option and reports it only when no --help or -h
follows.

apps/figcraft-cli/src/args.rs

@@ -16,6 +16,8 @@ pub struct Args {
 impl Args {
     pub fn parse(argv: &[String], valued: &[&str], flags: &[&str]) -> CliResult<Self> {
         let mut a = Args::default();
+        // The first bad option, reported once the rest of the line is checked for `--help`.
+        let mut bad: Option<CliError> = None;
         let mut it = argv.iter();
         while let Some(arg) = it.next() {
             let name = if let Some(n) = arg.strip_prefix("--") {
@@ -35,18 +37,22 @@ impl Args {
                 return Err(CliError::Help);
             }
             if valued.contains(&name) {
-                let v = match inline {
-                    Some(v) => v,
-                    None => it.next().cloned().ok_or_else(|| CliError::Usage(format!("`{arg}` needs a value")))?,
-                };
-                a.values.entry(name.to_string()).or_default().push(v);
+                match inline.or_else(|| it.next().cloned()) {
+                    Some(v) => a.values.entry(name.to_string()).or_default().push(v),
+                    None => {
+                        bad.get_or_insert(CliError::Usage(format!("`{arg}` needs a value")));
+                    }
+                }
             } else if flags.contains(&name) && inline.is_none() {
                 a.flags.push(name.to_string());
             } else {
-                return Err(CliError::Usage(format!("unknown option `{arg}`")));
+                bad.get_or_insert(CliError::Usage(format!("unknown option `{arg}`")));
             }
         }
-        Ok(a)
+        match bad {
+            Some(e) => Err(e),
+            None => Ok(a),
+        }
     }
 
     pub fn value(&self, k: &str) -> Option<String> {
@@ -142,7 +148,10 @@ mod tests {
 
     #[test]
     fn help_is_asked_for_anywhere_but_as_a_value() {
-        for argv in [&["--help"][..], &["-h"], &["in.figcraft", "-o", "out", "--help"], &["--json", "-h"]] {
+        // Also after a bad option: help wins over the usage error (#1161 review).
+        for argv in
+            [&["--help"][..], &["-h"], &["in.figcraft", "-o", "out", "--help"], &["--json", "-h"], &["--bogus", "--help"], &["--json=1", "-h"]]
+        {
             assert!(matches!(Args::parse(&v(argv), &["o"], &["json"]), Err(CliError::Help)), "{argv:?}");
         }
         let a = Args::parse(&v(&["--filter", "--help", "-o", "-h"]), &["filter", "o"], &[]).unwrap();

apps/figcraft-cli/tests/cli.rs

@@ -60,6 +60,7 @@ fn help_after_a_subcommand_prints_the_usage() {
         &["plugin", "publish", "--help"],
         &["perf", "--help"],
         &["mcp", "--attach", "notaport", "--help"],
+        &["mcp", "--bogus", "--help"],
     ] {
         let out = bin().args(args).stdin(Stdio::null()).output().unwrap();
         assert_eq!(out.status.code(), Some(0), "{args:?}: {}", String::from_utf8_lossy(&out.stderr));