From 3a19df702726f14c649af8c903f8d2146c7a61b5 Mon Sep 17 00:00:00 2001
From: hisayya <128133846+hisayya@users.noreply.github.com>
Date: Sat, 15 Aug 2026 16:36:52 +0000
Subject: [PATCH] fix: detect Linux serial ports in deploy.sh

deploy.sh only auto-detected the macOS Arduino path (/dev/cu.usbmodem*),
so Linux users (native USB CDC at /dev/ttyACM*, UART bridges at
/dev/ttyUSB*) had to set PORT manually or the script reported no port.

Scan both OS families with a find_port helper, keep the macOS paths for
regressions, and make the error message name every pattern checked.

Also document the hf CLI dependency that fetch_model.sh needs, which
the README previously omitted.

Tests: SerialPortIsAutoDetected stubs ls and verifies each family's port
is picked; all 29 deploy tests pass.
---
 README.md            | 12 ++++++++++++
 scripts/deploy.sh    | 19 +++++++++++++++----
 tests/test_deploy.py | 42 +++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 3458ede..95c65b5 100644
--- a/README.md
+++ b/README.md
@@ -77,6 +77,18 @@ scripts/deploy.sh barista        # generate headers, run gates, compile, flash
 the model to be named, because the board holds one at a time and deploying
 replaces it.
 
+Before the first fetch, install the Hugging Face CLI (`hf`), which
+`fetch_model.sh` requires to download the released assets:
+
+```bash
+uv tool install huggingface_hub   # provides `hf`
+```
+
+`deploy.sh` auto-detects the board's serial port on Linux
+(`/dev/ttyACM*` for native USB CDC, `/dev/ttyUSB*` for a UART bridge) and on
+macOS (`/dev/cu.usbmodem*`). If several ports match, or detection does not fit
+your wiring, pin it explicitly: `PORT=/dev/ttyACM0 scripts/deploy.sh barista`.
+
 `fetch_model.sh` checks the inference assets against a SHA-256 and byte size
 pinned in the script, and cross-checks the release's own `metadata.json` against
 those same pins. It installs nothing unless every check passes, so a failed
diff --git a/scripts/deploy.sh b/scripts/deploy.sh
index c06ab89..d406fe4 100755
--- a/scripts/deploy.sh
+++ b/scripts/deploy.sh
@@ -167,10 +167,21 @@ find_esptool() {
 }
 ESPTOOL=$(find_esptool)
 
-# `|| true`: a failing glob would otherwise abort the assignment under `set -e`,
-# before the message below can print.
-PORT=${PORT:-$(ls /dev/cu.usbmodem* 2>/dev/null | head -1 || true)}
-[ -n "$PORT" ] || { echo "no /dev/cu.usbmodem* found; plug the board in, or set PORT=..." >&2; exit 1; }
+# Both OS families name the same hardware differently: macOS calls the Arduino
+# bridge /dev/cu.usbmodem* (and older FTDI/CP210x boards /dev/cu.usbserial-*),
+# while Linux calls the native USB CDC device /dev/ttyACM* and a UART bridge
+# /dev/ttyUSB*. Scan them all so the same command works on either platform.
+# With more than one board attached the first match is arbitrary, so the
+# message tells the user to set PORT to the exact path.
+find_port() {
+  local pat
+  for pat in /dev/ttyACM* /dev/ttyUSB* /dev/cu.usbmodem* /dev/cu.usbserial-*; do
+    ls $pat 2>/dev/null && return 0
+  done
+  return 0
+}
+PORT=${PORT:-$(find_port | head -1)}
+[ -n "$PORT" ] || { echo "no serial port found (looked for /dev/ttyACM*, /dev/ttyUSB*, /dev/cu.usbmodem*); plug the board in, or set PORT=/dev/ttyACM0 (Linux) or PORT=/dev/cu.usbmodemNNNN (macOS)" >&2; exit 1; }
 
 # Every required artifact is checked before anything is generated or built, so a
 # missing file is reported as a list rather than discovered halfway through.
diff --git a/tests/test_deploy.py b/tests/test_deploy.py
index 1f379a6..a84f66d 100644
--- a/tests/test_deploy.py
+++ b/tests/test_deploy.py
@@ -351,9 +351,49 @@ def test_a_missing_port_stops_before_generating(self):
                                    "vocab.json", "layout.json"])
         r = self.run_deploy("barista", PORT="")
         self.assertNotEqual(r.returncode, 0)
-        self.assertIn("no /dev/cu.usbmodem*", r.stderr)
+        self.assertIn("no serial port found", r.stderr)
         self.assertEqual(self.calls(), [])
 
 
+class SerialPortIsAutoDetected(DeployHarness):
+    """deploy.sh picks a port when PORT is unset. The scan covers both OS
+    families: Linux names the board /dev/ttyACM* or /dev/ttyUSB*, macOS
+    /dev/cu.usbmodem*. These tests stub `ls` so they are independent of the
+    hardware attached to the runner."""
+
+    def setUp(self):
+        super().setUp()
+        self.artifacts("barista", ["model.bin", "tokenizer.json",
+                                   "vocab.json", "layout.json"])
+
+    def run_with_ls(self, ls_body):
+        stub_ls = self.bin / "ls"
+        stub_ls.write_text(ls_body)
+        os.chmod(stub_ls, 0o755)
+        return self.run_deploy("barista", PORT="")
+
+    def test_linux_ttyACM_is_detected(self):
+        r = self.run_with_ls("""#!/bin/sh
+case "$1" in
+  /dev/ttyACM*) echo /dev/ttyACM0; exit 0 ;;
+  *) exit 1 ;;
+esac
+""")
+        self.assertEqual(r.returncode, 0, r.stderr)
+        flash = [c for c in self.calls() if "write_flash" in c]
+        self.assertIn("/dev/ttyACM0", flash[0])
+
+    def test_macos_cu_usbmodem_is_detected(self):
+        r = self.run_with_ls("""#!/bin/sh
+case "$1" in
+  /dev/cu.usbmodem*) echo /dev/cu.usbmodem1410; exit 0 ;;
+  *) exit 1 ;;
+esac
+""")
+        self.assertEqual(r.returncode, 0, r.stderr)
+        flash = [c for c in self.calls() if "write_flash" in c]
+        self.assertIn("/dev/cu.usbmodem1410", flash[0])
+
+
 if __name__ == "__main__":
     unittest.main()