Add defensive error handling to prevent exit code 1 on Windows

- downloader.py: wrap canvasapi/requests/tqdm imports in try/except;
  guard CANVAS_URL/CANVAS_TOKEN before use; wrap Canvas() ctor in try/except
- semantic_alignment.py: wrap faiss/numpy top-level imports in try/except
- note_generation.py: wrap tqdm/alignment_parser imports in try/except
- electron/main.js: pre-flight check Python exe and script file existence
  before spawning; upgrade pipe-mode error handler to show actionable hint
  on ENOENT (python not found)

Author: nodeeeeee

downloader.py

@@ -29,9 +29,14 @@
 from datetime import datetime, timezone
 from pathlib import Path
 
-import requests
-from canvasapi import Canvas
-from tqdm import tqdm
+try:
+    import requests
+    from canvasapi import Canvas
+    from tqdm import tqdm
+except ImportError as _e:
+    print(f"[error] Missing dependency: {_e}")
+    print("[error] Please install the ML environment from Settings → ML Environment in the AutoNote app.")
+    sys.exit(1)
 
 # ── Configuration ──────────────────────────────────────────────────────────────
 
@@ -1059,8 +1064,21 @@ def main() -> None:
         parser.print_help()
         sys.exit(0)
 
+    if not CANVAS_URL:
+        print("[error] Canvas URL is not configured.")
+        print("[error] Enter your Canvas URL in Settings → Connection in the AutoNote app.")
+        sys.exit(1)
+    if not CANVAS_TOKEN:
+        print("[error] Canvas token is not configured.")
+        print("[error] Enter your Canvas API token in Settings → API Keys in the AutoNote app.")
+        sys.exit(1)
+
     base_dir = Path(args.path) if args.path else DATA_DIR
-    canvas   = Canvas(CANVAS_URL, CANVAS_TOKEN)
+    try:
+        canvas = Canvas(CANVAS_URL, CANVAS_TOKEN)
+    except Exception as e:
+        print(f"[error] Failed to connect to Canvas: {e}")
+        sys.exit(1)
 
     # ── --course-list ──────────────────────────────────────────────────────────
     if args.course_list:

electron/main.js

@@ -342,9 +342,33 @@ let installProc = null;
 let mainWindow  = null;
 
 // ── Subprocess runner (pipeline scripts) ─────────────────────────────────────
+function sendProcessError(msg) {
+  mainWindow?.webContents.send('process:data', msg + '\n');
+  mainWindow?.webContents.send('process:done', { code: 1 });
+}
+
 function runProcess(cmd) {
   if (activeProc) return { error: 'Already running — stop it first.' };
 
+  // ── Pre-flight validation ──────────────────────────────────────────────────
+  const [pythonExe, scriptFile] = cmd;
+
+  // Validate Python executable: if it looks like an absolute path, check it exists.
+  if (pythonExe && path.isAbsolute(pythonExe) && !fs.existsSync(pythonExe)) {
+    sendProcessError(
+      `[error] Python executable not found: ${pythonExe}\n` +
+      `[error] Please install the ML environment from Settings → ML Environment,\n` +
+      `[error] or configure a valid Python path in Settings → Connection.`
+    );
+    return { ok: true };
+  }
+
+  // Validate script file exists.
+  if (scriptFile && path.isAbsolute(scriptFile) && !fs.existsSync(scriptFile)) {
+    sendProcessError(`[error] Script not found: ${scriptFile}`);
+    return { ok: true };
+  }
+
   const outDir = getOutputDir();
   fs.mkdirSync(outDir, { recursive: true });
   const env = {
@@ -393,7 +417,11 @@ function runProcess(cmd) {
   });
   proc.on('error', err => {
     activeProc = null;
-    mainWindow?.webContents.send('process:done', { code: -1, error: err.message });
+    const hint = err.code === 'ENOENT'
+      ? `\n[error] Could not find executable: ${prog}\n[error] Install the ML environment from Settings → ML Environment.`
+      : '';
+    mainWindow?.webContents.send('process:data', `[error] ${err.message}${hint}\n`);
+    mainWindow?.webContents.send('process:done', { code: 1 });
   });
   return { ok: true };
 }

note_generation.py

@@ -25,9 +25,19 @@
 from datetime import datetime
 from pathlib import Path
 
-from tqdm import tqdm
-
-import alignment_parser
+try:
+    from tqdm import tqdm
+except ImportError as _e:
+    print(f"[error] Missing dependency: {_e}")
+    print("[error] Please install the ML environment from Settings → ML Environment in the AutoNote app.")
+    sys.exit(1)
+
+try:
+    import alignment_parser
+except ImportError as _e:
+    print(f"[error] Could not import alignment_parser: {_e}")
+    print(f"[error] Make sure alignment_parser.py is in the same directory as note_generation.py")
+    sys.exit(1)
 
 PROJECT_DIR = Path(__file__).parent
 import sys as _sys

semantic_alignment.py

@@ -35,8 +35,13 @@
 from pathlib import Path
 from typing import NamedTuple
 
-import faiss
-import numpy as np
+try:
+    import faiss
+    import numpy as np
+except ImportError as _e:
+    print(f"[error] Missing dependency: {_e}")
+    print("[error] Please install the ML environment from Settings → ML Environment in the AutoNote app.")
+    sys.exit(1)
 
 PROJECT_DIR = Path(__file__).parent
 import sys as _sys