Fix/error code hints 215

.github/workflows/test-error-code-hints.yaml

@@ -0,0 +1,49 @@
+name: Test error code hints
+
+on:
+  push:
+    branches: ["*"]
+  pull_request:
+    branches: [dev, main]
+
+jobs:
+  test-error-code-hints:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install mlcflow
+        run: pip install -e .
+
+      - name: Test exit code hint helper
+        run: |
+          python -c "
+          from mlc.script_action import _get_exit_code_hint, ScriptExecutionError
+
+          # Known codes return specific hints
+          assert 'Segmentation fault' in _get_exit_code_hint(139)
+          assert 'disk space' in _get_exit_code_hint(28).lower()
+          assert 'Network error' in _get_exit_code_hint(6)
+          assert 'Network error' in _get_exit_code_hint(7)
+          assert 'PATH' in _get_exit_code_hint(127)
+
+          # Unknown code returns generic fallback with the code number
+          hint = _get_exit_code_hint(999)
+          assert '999' in hint
+
+          # ScriptExecutionError embeds hint in message
+          err = ScriptExecutionError('test failed', return_code=139)
+          assert 'Segmentation fault' in str(err)
+          assert err.return_code == 139
+
+          # return_code=-1 means no hint appended
+          err2 = ScriptExecutionError('test failed')
+          assert str(err2) == 'test failed'
+
+          print('All assertions passed.')
+          "

.gitignore

@@ -2,5 +2,5 @@ build
 dist
 *egg-info
 __pycache__
-
+.vscode
 .mlc-log.txt

README.md

@@ -18,6 +18,8 @@ On February 9, 2025, MLCFlow released its first stable version, 1.0.0.
 ### Key Features
 Building upon the core idea of CMind—wrapping native scripts with Python wrappers and YAML metadata—MLCFlow focuses exclusively on key automation components: **Scripts**, along with its complementary modules: **Cache**, **Docker**, and **Experiments**. This targeted design simplifies both implementation and interface, enabling a more user-friendly experience.
 
+- **Smart Error Messages**: When a script fails, MLCFlow now detects the exit code and displays a human-readable suggestion — for example, flagging network issues, disk space problems, permission errors, or segmentation faults — so you spend less time debugging.
+
 ---
 
 ### Status

mlc/script_action.py

@@ -9,6 +9,37 @@
 from . import utils
 from .logger import logger
 
+_SCRIPT_EXIT_CODE_HINTS: dict[int, str] = {
+    1: "General error. Review the script output above for details.",
+    2: "Shell misuse or invalid argument passed to the script.",
+    13: "Permission denied. Check file or directory permissions.",
+    28: "No space left on device. Free up disk space and retry.",
+    126: "Command cannot execute. Check execute permissions on the script.",
+    127: "Command not found. Ensure all required dependencies are installed and on PATH.",
+    130: "Script interrupted by user (Ctrl+C / SIGINT).",
+    137: "Process killed (SIGKILL). Possible out-of-memory condition.",
+    139: "Segmentation fault in native run. Check your binary or native library.",
+    143: "Script terminated externally (SIGTERM).",
+}
+
+
+def _get_exit_code_hint(return_code: int) -> str:
+    """Return a human-readable hint for a subprocess exit code.
+    Falls back to a generic message for unknown codes.
+    Network-error heuristic: codes 6/7 are curl exit codes for DNS / connect
+    failures, often surfaced as return_code=6 or 7 inside scripts.
+    """
+    if return_code in (6, 7):
+        return (
+            "Network error detected (DNS resolution or connection failure). "
+            "Check your internet connection and proxy settings."
+        )
+    return _SCRIPT_EXIT_CODE_HINTS.get(
+        return_code,
+        f"Script exited with code {return_code}. "
+        "See the output above for more details.",
+    )
+
 
 class ScriptAction(Action):
     """
@@ -312,10 +343,14 @@ def call_script_module_function(self, function_name, run_args):
                 _repo_alias = _repo_match.group(1) if _repo_match else None
                 _script_name = run_args.get('tags', run_args.get('details'))
                 raise ScriptExecutionError(
-                    f"Script {function_name} execution failed in {module_path}." +
-                    "\nError : " + f"{type(exc).__name__}: {exc}",
-                    script_name=_script_name, repo_alias=_repo_alias, module_path=module_path,
-                    run_args=run_args) from exc
+                    f"Script {function_name} execution failed in {
+                        module_path}. \nError : {error}",
+                    script_name=_script_name,
+                    repo_alias=_repo_alias,
+                    module_path=module_path,
+                    run_args=run_args,
+                    version_info_file=_version_info_file,
+                    return_code=result.get("return", -1), )
 
             if result['return'] > 0:
                 error = result.get('error', "")
@@ -336,7 +371,8 @@ def call_script_module_function(self, function_name, run_args):
                     except Exception:
                         _version_info_file = None
                 raise ScriptExecutionError(
-                    f"Script {function_name} execution failed in {module_path}. \nError : {error}",
+                    f"Script {function_name} execution failed in {
+                        module_path}. \nError : {error}",
                     script_name=_script_name, repo_alias=_repo_alias, module_path=module_path,
                     run_args=run_args, version_info_file=_version_info_file)
 
@@ -679,11 +715,23 @@ def remote_docker(self, run_args):
 
 
 class ScriptExecutionError(Exception):
-    def __init__(self, message, script_name=None, repo_alias=None,
-                 module_path=None, run_args=None, version_info_file=None):
-        super().__init__(message)
+    def __init__(
+        self,
+        message,
+        script_name=None,
+        repo_alias=None,
+        module_path=None,
+        run_args=None,
+        version_info_file=None,
+        return_code: int = -1,
+    ):
+        hint = _get_exit_code_hint(return_code) if return_code != -1 else ""
+        full_message = f"{message}\n[Exit code {return_code}] {
+            hint}" if hint else message
+        super().__init__(full_message)
         self.script_name = script_name
         self.repo_alias = repo_alias
         self.module_path = module_path
         self.run_args = run_args or {}
         self.version_info_file = version_info_file
+        self.return_code = return_code