refactor(cli): consolidate format helpers onto render::format / render::json

CHANGELOG.md

@@ -6,6 +6,8 @@ Cross-package release notes for relayburn. Package changelogs contain package-le
 
 ### Changed
 
+- `relayburn-cli`: stdout-write failures in `--json` mode now surface as a
+  non-zero exit instead of being silently dropped.
 - `relayburn-sdk`: ledger query verbs (`query_turns`, `query_compactions`,
   `query_relationships`, `query_tool_result_events`, `query_user_turns`)
   now push `since` / `until` / `session_id` / `source` / `project` filters

crates/relayburn-cli/src/commands/compare.rs

@@ -21,6 +21,7 @@ use serde_json::{json, Value};
 
 use crate::cli::{CompareArgs, GlobalArgs};
 use crate::render::error::report_error;
+use crate::render::format::{format_uint, format_usd};
 use crate::render::json::render_json;
 use crate::render::progress::TaskProgress;
 
@@ -492,44 +493,6 @@ fn days_to_ymd(days_from_epoch: i64) -> (i64, u32, u32) {
 // number formatting (matches packages/cli/src/format.ts)
 // ---------------------------------------------------------------------------
 
-fn format_usd(n: f64) -> String {
-    if n == 0.0 {
-        return "$0.00".to_string();
-    }
-    if n < 0.01 {
-        return format!("${}", to_fixed_raw(n, 4));
-    }
-    if n < 1.0 {
-        return format!("${}", to_fixed_raw(n, 3));
-    }
-    format!("${}", to_fixed_raw(n, 2))
-}
-
-/// Mirror JS `n.toFixed(d)` — keeps trailing zeros (so 1.5 with digits=2
-/// becomes "1.50"). Use this for human-readable output where the
-/// fixed-width column matters; use [`to_fixed`] for JSON-bound values
-/// that go through `Number(...).toString()` semantics.
-fn to_fixed_raw(n: f64, digits: usize) -> String {
-    format!("{n:.*}", digits)
-}
-
-fn format_int(n: u64) -> String {
-    // `toLocaleString('en-US')` thousands grouping. JS uses `,`. The
-    // golden corpus values are small (≤ 7) so the comma path isn't hit
-    // by the snapshot, but we implement it anyway for parity.
-    let s = n.to_string();
-    let bytes = s.as_bytes();
-    let mut out = String::with_capacity(s.len() + s.len() / 3);
-    let len = bytes.len();
-    for (i, b) in bytes.iter().enumerate() {
-        if i > 0 && (len - i).is_multiple_of(3) {
-            out.push(',');
-        }
-        out.push(*b as char);
-    }
-    out
-}
-
 fn format_pct(rate: f64) -> String {
     // `Math.round(p * 100)` — round half to even on f64; matches JS for
     // the corpus we compare against (the `Math.round` half-to-even
@@ -885,7 +848,7 @@ fn cell_fields(c: &CompareCell) -> [String; 3] {
     if c.no_data {
         return [DASH.to_string(), DASH.to_string(), DASH.to_string()];
     }
-    let turns = format_int(c.turns);
+    let turns = format_uint(c.turns);
     let cost = c
         .cost_per_turn
         .map(format_usd)
@@ -905,7 +868,7 @@ fn render_tty(
 ) -> String {
     let mut lines: Vec<String> = Vec::new();
     lines.push(String::new());
-    lines.push(format!("turns analyzed: {}", format_int(analyzed_turns as u64)));
+    lines.push(format!("turns analyzed: {}", format_uint(analyzed_turns as u64)));
 
     let excluded = compute_excluded(summary, minimum);
     if excluded.total > 0 {
@@ -1044,7 +1007,7 @@ fn render_tty(
         lines.push(format!(
             "{}: {} turns, {} total",
             display_model_name(m),
-            format_int(tot.turns),
+            format_uint(tot.turns),
             total_cost
         ));
     }
@@ -1121,7 +1084,7 @@ fn format_excluded_note(excluded: &ExcludedBreakdown, minimum: FidelityClass) ->
     let noun = if excluded.total == 1 { "turn" } else { "turns" };
     format!(
         "excluded {} {noun} below {} fidelity{breakdown}",
-        format_int(excluded.total),
+        format_uint(excluded.total),
         minimum.wire_str()
     )
 }
@@ -1130,22 +1093,6 @@ fn format_excluded_note(excluded: &ExcludedBreakdown, minimum: FidelityClass) ->
 mod tests {
     use super::*;
 
-    #[test]
-    fn format_usd_buckets() {
-        assert_eq!(format_usd(0.0), "$0.00");
-        assert_eq!(format_usd(0.0017), "$0.0017");
-        assert_eq!(format_usd(0.011), "$0.011");
-        assert_eq!(format_usd(0.034), "$0.034");
-        assert_eq!(format_usd(1.5), "$1.50");
-    }
-
-    #[test]
-    fn format_int_groups_thousands() {
-        assert_eq!(format_int(7), "7");
-        assert_eq!(format_int(1_500), "1,500");
-        assert_eq!(format_int(1_000_000), "1,000,000");
-    }
-
     #[test]
     fn format_pct_rounds_to_int() {
         assert_eq!(format_pct(0.0), "0%");

crates/relayburn-cli/src/commands/hotspots.rs

@@ -36,6 +36,7 @@ use serde_json::{json, Map, Value};
 use crate::cli::GlobalArgs;
 use crate::render::error::report_error;
 use crate::render::format::{coerce_whole_f64_to_int, format_uint, format_usd, render_table};
+use crate::render::json::render_json;
 use crate::render::progress::TaskProgress;
 
 const DEFAULT_TOP_N: usize = 10;
@@ -254,20 +255,18 @@ fn run_inner(globals: &GlobalArgs, args: HotspotsArgs) -> anyhow::Result<i32> {
     progress.finish_and_clear();
 
     if globals.json {
-        emit_json(&result);
+        emit_json(&result)?;
         return Ok(0);
     }
     let limit = if args.all { usize::MAX } else { DEFAULT_TOP_N };
     emit_human(&result, limit, args.findings);
     Ok(0)
 }
 
-fn emit_json(result: &HotspotsResult) {
+fn emit_json(result: &HotspotsResult) -> std::io::Result<()> {
     let mut value = hotspots_result_to_json(result);
     coerce_whole_f64_to_int(&mut value);
-    let mut out = serde_json::to_string_pretty(&value).unwrap_or_default();
-    out.push('\n');
-    print!("{}", out);
+    render_json(&value)
 }
 
 fn hotspots_result_to_json(result: &HotspotsResult) -> Value {