From 62b9b5acd468a5988bccb01625f7beb867e64ce7 Mon Sep 17 00:00:00 2001
From: midasmatterhorn <248507632+midasmatterhorn@users.noreply.github.com>
Date: Tue, 27 Oct 2026 00:58:10 +0300
Subject: [PATCH 1/3] engine: save, render and export create a missing target
 folder instead of failing with os error 3

---
 crates/engine/src/atomic_write.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/crates/engine/src/atomic_write.rs b/crates/engine/src/atomic_write.rs
index ff9e141d3..cd7d0fb4b 100644
--- a/crates/engine/src/atomic_write.rs
+++ b/crates/engine/src/atomic_write.rs
@@ -37,6 +37,9 @@ pub fn write_atomic(path: &Path, bytes: &[u8]) -> io::Result<()> {
         Err(e) => return Err(e),
     };
     let dir = path.parent().filter(|p| !p.as_os_str().is_empty()).map_or_else(|| PathBuf::from("."), Path::to_path_buf);
+    if let Err(e) = std::fs::create_dir_all(&dir) {
+        return Err(e);
+    }
     let (mut file, tmp) = create_temp(&dir, permissions.as_ref())?;
     let write = (|| {
         if let Some(permissions) = permissions {
@@ -101,6 +104,15 @@ fn create_exclusive(path: &Path, permissions: Option<&Permissions>) -> io::Resul
 mod tests {
     use super::*;
 
+    #[test]
+    fn creates_missing_parent_directories() {
+        let dir = std::env::temp_dir().join(format!("cadcraft-aw-mkdir-{}-{}", std::process::id(), SEQ.fetch_add(1, Ordering::Relaxed)));
+        let dest = dir.join("new_folder").join("out.bin");
+        write_atomic(&dest, b"created").unwrap();
+        assert_eq!(std::fs::read(&dest).unwrap(), b"created");
+        std::fs::remove_dir_all(&dir).ok();
+    }
+
     #[test]
     fn replaces_contents_atomically() {
         let dir = std::env::temp_dir().join(format!("cadcraft-aw-{}-{}", std::process::id(), SEQ.fetch_add(1, Ordering::Relaxed)));

From c2cb5b86109b4df3a822a29ac0d706284e0c7b54 Mon Sep 17 00:00:00 2001
From: midasmatterhorn <236787783+midasmatterhorn@users.noreply.github.com>
Date: Thu, 29 Oct 2026 21:49:48 +0300
Subject: [PATCH 2/3] engine: propagate create_dir_all errors and route render
 PNG writes through write_atomic

---
 crates/engine/src/atomic_write.rs | 4 +---
 crates/mcp/src/backend.rs         | 3 ++-
 crates/ui-egui/src/control.rs     | 2 +-
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/crates/engine/src/atomic_write.rs b/crates/engine/src/atomic_write.rs
index cd7d0fb4b..2d05e019d 100644
--- a/crates/engine/src/atomic_write.rs
+++ b/crates/engine/src/atomic_write.rs
@@ -37,9 +37,7 @@ pub fn write_atomic(path: &Path, bytes: &[u8]) -> io::Result<()> {
         Err(e) => return Err(e),
     };
     let dir = path.parent().filter(|p| !p.as_os_str().is_empty()).map_or_else(|| PathBuf::from("."), Path::to_path_buf);
-    if let Err(e) = std::fs::create_dir_all(&dir) {
-        return Err(e);
-    }
+    std::fs::create_dir_all(&dir)?;
     let (mut file, tmp) = create_temp(&dir, permissions.as_ref())?;
     let write = (|| {
         if let Some(permissions) = permissions {
diff --git a/crates/mcp/src/backend.rs b/crates/mcp/src/backend.rs
index 9d012076a..d27012418 100644
--- a/crates/mcp/src/backend.rs
+++ b/crates/mcp/src/backend.rs
@@ -395,7 +395,8 @@ impl Backend for Headless {
                 let png =
                     cadcraft_render::raster::render_png(&list, &view, &cadcraft_render::raster::RasterOptions::default()).ok_or("render failed")?;
                 if let Some(path) = str_p("path") {
-                    std::fs::write(&path, &png).map_err(|e| format!("{path}: {e}"))?;
+                    cadcraft_engine::atomic_write::write_atomic(std::path::Path::new(&path), &png)
+                        .map_err(|e| format!("{path}: {e}"))?;
                 }
                 Ok(json!({"pngBase64": cadcraft_engine::cmd::file::base64_encode(&png), "width": w, "height": h}))
             }
diff --git a/crates/ui-egui/src/control.rs b/crates/ui-egui/src/control.rs
index 2dc1f898a..4370b5de1 100644
--- a/crates/ui-egui/src/control.rs
+++ b/crates/ui-egui/src/control.rs
@@ -489,7 +489,7 @@ pub fn handle(app: &mut CadApp, ctx: &egui::Context, req: &ControlRequest) -> Ou
             };
             #[cfg(not(target_arch = "wasm32"))]
             if let Some(path) = s("path") {
-                if let Err(e) = std::fs::write(path, &png) {
+                if let Err(e) = cadcraft_engine::atomic_write::write_atomic(std::path::Path::new(&path), &png) {
                     return err(e);
                 }
                 return ok(render_reply(&png, w, h, Some(path)));

From 9c84141e3899bd17a5747e578b11bcbf91ad28e1 Mon Sep 17 00:00:00 2001
From: midasmatterhorn <248507632+midasmatterhorn@users.noreply.github.com>
Date: Sun, 1 Nov 2026 04:56:59 +0300
Subject: [PATCH 3/3] style: rustfmt the write_atomic map_err in render

---
 crates/mcp/src/backend.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/crates/mcp/src/backend.rs b/crates/mcp/src/backend.rs
index d27012418..4ed805979 100644
--- a/crates/mcp/src/backend.rs
+++ b/crates/mcp/src/backend.rs
@@ -395,8 +395,7 @@ impl Backend for Headless {
                 let png =
                     cadcraft_render::raster::render_png(&list, &view, &cadcraft_render::raster::RasterOptions::default()).ok_or("render failed")?;
                 if let Some(path) = str_p("path") {
-                    cadcraft_engine::atomic_write::write_atomic(std::path::Path::new(&path), &png)
-                        .map_err(|e| format!("{path}: {e}"))?;
+                    cadcraft_engine::atomic_write::write_atomic(std::path::Path::new(&path), &png).map_err(|e| format!("{path}: {e}"))?;
                 }
                 Ok(json!({"pngBase64": cadcraft_engine::cmd::file::base64_encode(&png), "width": w, "height": h}))
             }