#1005: vectorcraft-cli run ends quietly when its reader closes early

`run` reported "Broken pipe" (on Windows "The pipe is being closed") and exited 1 when the
reader of its stdout went away, unlike `commands` and the other subcommands, which end quietly.

Its step printer now treats a closed pipe as the end of output, not an error: the remaining
steps still run (an export is still written), unprinted, and the run exits 0. Other write
errors and failing steps still fail.

The test runs document.json, a rectangle and an SVG export with stdout closed: status 0, empty
stderr, the SVG written; `run --cmd not-a-command` still fails.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

# Conflicts:
#	ROADMAP.md

ROADMAP.md

@@ -123,7 +123,7 @@ Ranked; detail in [docs/roadmap.md](docs/roadmap.md) and [docs/gaps.md](docs/gap
 
 | Date | What landed |
 |---|---|
-| 2026-10-11 | Effect › Brush Strokes: Accented Edges, Angled Strokes, Crosshatch, Dark Strokes, Ink Outlines, Spatter, Sprayed Strokes, Sumi-e (G2). Command parameters from agents and files checked before anything changes (paint, place, cuts, dashes, crop, asset ids, anchors, paths, distort; #984–#999); command dialogs keep whole numbers whole, so Create Object Mosaic takes the tiles typed (#1000); stepper arrows take Shift (×10) and Ctrl/Cmd (÷10) like the arrow keys (#991). Exports and Rasterize supersample Art Optimized edges, so shapes meeting edge to edge leave no seam (#983). Character and paragraph styles take leading, kerning, mojikumi and the other attributes left out at their defaults (#1001). Drawing, typing and pasting with no layer shown and unlocked is refused instead of adding art to a hidden or locked layer (#1002). MCP `add_text` gives type on or in a path the colour asked for (#1003). MCP `screenshot` of a connected app renders the artboard asked for (#1004). |
+| 2026-10-11 | Effect › Brush Strokes: Accented Edges, Angled Strokes, Crosshatch, Dark Strokes, Ink Outlines, Spatter, Sprayed Strokes, Sumi-e (G2). Command parameters from agents and files checked before anything changes (paint, place, cuts, dashes, crop, asset ids, anchors, paths, distort; #984–#999); command dialogs keep whole numbers whole, so Create Object Mosaic takes the tiles typed (#1000); stepper arrows take Shift (×10) and Ctrl/Cmd (÷10) like the arrow keys (#991). Exports and Rasterize supersample Art Optimized edges, so shapes meeting edge to edge leave no seam (#983). Character and paragraph styles take leading, kerning, mojikumi and the other attributes left out at their defaults (#1001). Drawing, typing and pasting with no layer shown and unlocked is refused instead of adding art to a hidden or locked layer (#1002). MCP `add_text` gives type on or in a path the colour asked for (#1003). MCP `screenshot` of a connected app renders the artboard asked for (#1004). `vectorcraft-cli run` ends quietly when its reader closes early (#1005). |
 | 2026-10-10 | Initial live Revolve (Effect › 3D and Materials, #846, #605), in its own `three-d` crate. Progress docs re-measured and restructured to the craftrules standard (this page, `docs/target-app-parity.md`, `gaps.md`, `ui-parity.md`, the format, hardware, localization, effects and type checklists). Same day: v0.8.0; Effect › Distort, Pixelate and Texture filters (13); German interface; Variables (data merge); Graph Type value axes and tick marks; restart when the first frame never reaches the screen (#964) |
 | 2026-10-09 | Radial Blur, Smart Blur, Unsharp Mask (gap 2 begins); 340 commits, the busiest day |
 | 2026-10-08 | v0.5.0–v0.7.0; community contributions: Pen and shape-tool modifiers, Layers, Artboards, Japanese composition, Hebrew/Arabic type, interface languages, saved selections |

apps/vectorcraft-cli/src/main.rs

@@ -292,7 +292,21 @@ fn run(args: &[String]) -> Result<(), String> {
 
     let mut h = Headless::new();
     let mut out = std::io::stdout().lock();
-    let mut emit = |v: Value| writeln!(out, "{v}").map_err(|e| e.to_string());
+    // A reader that stopped early (a closed pipe) isn't an error, and the batch goes on: its later
+    // steps (an export…) still run, unprinted.
+    let mut closed = false;
+    let mut emit = |v: Value| {
+        if closed {
+            return Ok(());
+        }
+        match writeln!(out, "{v}") {
+            Err(e) if e.kind() == std::io::ErrorKind::BrokenPipe => {
+                closed = true;
+                Ok(())
+            }
+            r => r.map_err(|e| e.to_string()),
+        }
+    };
     if let Some(path) = &input {
         let r = h.call("app.open", json!({"path": path})).map_err(|e| format!("open {path}: {e}"))?;
         emit(json!({"step": "open", "path": path, "result": r}))?;

apps/vectorcraft-cli/tests/cli.rs

@@ -297,3 +297,21 @@ fn closed_stdout_ends_quietly() {
     let err = String::from_utf8_lossy(&out.stderr);
     assert!(out.status.success() && !err.contains("panicked"), "{:?}: {err}", out.status);
 }
+
+/// #1005: `run` whose reader has gone (`vectorcraft-cli run … | true`) ends quietly with status 0,
+/// and its later steps still run; a failing step still fails.
+#[test]
+fn run_with_a_closed_stdout_ends_quietly_and_finishes_the_batch() {
+    let svg = tmp("closed-run.svg");
+    let _ = std::fs::remove_file(&svg);
+    let rect = r#"{"x":1,"y":1,"width":5,"height":5}"#;
+    let args = ["run", "--cmd", "document.json", "--cmd", "shape.rectangle", "--params", rect, "--export", svg.to_str().unwrap()];
+    let mut child = Command::new(BIN).args(args).stdout(Stdio::piped()).stderr(Stdio::piped()).spawn().unwrap();
+    drop(child.stdout.take());
+    let out = child.wait_with_output().unwrap();
+    let err = String::from_utf8_lossy(&out.stderr);
+    assert!(out.status.success() && err.is_empty(), "{:?}: {err}", out.status);
+    assert!(svg.is_file(), "the export after the closed reader still ran");
+    let out = Command::new(BIN).args(["run", "--cmd", "not-a-command"]).stdout(Stdio::null()).output().unwrap();
+    assert!(!out.status.success());
+}