crates/aura-cli/src/main.rs

@@ -2740,6 +2740,8 @@ struct DataCmd {
 enum DataCommand {
     /// Report a symbol's monthly file-index coverage (span + interior gaps).
     Coverage(DataCoverageCmd),
+    /// List the archive's known symbols, sorted, one per line.
+    List,
 }
 
 #[derive(Args)]
@@ -3674,9 +3676,37 @@ fn dispatch_nodes_new(a: NodesNewCmd) {
 fn dispatch_data(cmd: DataCmd, env: &project::Env) {
     match cmd.command {
         DataCommand::Coverage(a) => dispatch_data_coverage(a, env),
+        DataCommand::List => dispatch_data_list(env),
     }
 }
 
+/// `aura data list` (#264 cut 2): print the archive's known symbols, sorted
+/// ascending, one per line — the discovery step before `aura data coverage`
+/// or scoping a campaign's instrument matrix. Resolves the archive root
+/// through the normal project path ([`dispatch_data_coverage`]'s
+/// `Env::data_path`), then reuses `DataServer`'s own symbol index
+/// (`DataServer::symbols()`, already sorted) rather than re-deriving a
+/// directory scan. An empty or absent archive is informational absence, not a
+/// fault: a `no symbols` prose line, exit 0 (the verb corpus's established
+/// empty-result register — cf. `runs family`'s unknown-id empty exit 0).
+fn dispatch_data_list(env: &project::Env) {
+    let data_path = std::path::PathBuf::from(env.data_path());
+    let server = aura_ingest::DataServer::new(&data_path);
+    for line in data_list_report(&server.symbols()) {
+        println!("{line}");
+    }
+}
+
+/// Pure: render `symbols` (already sorted by `DataServer::symbols()`) as one
+/// line per symbol, or a single `no symbols` line when the archive is empty
+/// or absent — informational absence, never a fault (#264).
+fn data_list_report(symbols: &[std::sync::Arc<str>]) -> Vec<String> {
+    if symbols.is_empty() {
+        return vec!["no symbols".to_string()];
+    }
+    symbols.iter().map(|s| s.to_string()).collect()
+}
+
 /// `aura data coverage <SYMBOL>` (#264 cut 1): print the archive's month
 /// coverage for `SYMBOL` — the Copper failure mode (files present at both
 /// ends of a window while an interior month is missing, so a first/last-bounds
@@ -4203,6 +4233,26 @@ mod tests {
         );
     }
 
+    /// An empty (or absent) archive is informational absence, not a fault
+    /// (#264): `data_list_report` returns the single `no symbols` prose line
+    /// rather than an empty `Vec`, so the caller's exit-0 println always has
+    /// something to say.
+    #[test]
+    fn data_list_report_of_an_empty_archive_is_a_no_symbols_line() {
+        let symbols: Vec<std::sync::Arc<str>> = vec![];
+        assert_eq!(data_list_report(&symbols), vec!["no symbols".to_string()]);
+    }
+
+    /// A non-empty archive renders one line per symbol, in the order handed
+    /// in (`DataServer::symbols()` already sorts) — no `no symbols` line
+    /// mixed in (#264).
+    #[test]
+    fn data_list_report_of_a_populated_archive_is_one_line_per_symbol() {
+        let symbols: Vec<std::sync::Arc<str>> =
+            vec![std::sync::Arc::from("SYMA"), std::sync::Arc::from("SYMB")];
+        assert_eq!(data_list_report(&symbols), vec!["SYMA".to_string(), "SYMB".to_string()]);
+    }
+
     /// Disjoint archives (no shared instant across all listed symbols) refuse
     /// rather than silently pooling a floor over different periods per
     /// instrument (#213); the error names each symbol next to its own span,