Merge pull request #1995 from plotly/1992-fix-debugger

alexcjohnson · web-flow · commit 89973c04d011 · 2022-03-29T16:54:26.000-04:00
Fix werkzeug 2.1.0 import &amp; dev tools error html rendering.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ### Fixed
 
 - [#1963](https://github.com/plotly/dash/pull/1963) Fix [#1780](https://github.com/plotly/dash/issues/1780) flask shutdown deprecation warning when running dashduo threaded tests.
+- [#1995](https://github.com/plotly/dash/pull/1995) Fix [#1992](https://github.com/plotly/dash/issues/1992) ImportError: cannot import name 'get_current_traceback' from 'werkzeug.debug.tbtools'.
 
 ## [2.3.0] - 2022-03-13
 
diff --git a/dash/_utils.py b/dash/_utils.py
@@ -8,6 +8,8 @@
 import logging
 import io
 import json
+import secrets
+import string
 from functools import wraps
 
 logger = logging.getLogger()
@@ -206,3 +208,9 @@ def _wrapper(*args, **kwargs):
         return _wrapper
 
     return wrapper
+
+
+def gen_salt(chars):
+    return "".join(
+        secrets.choice(string.ascii_letters + string.digits) for _ in range(chars)
+    )
diff --git a/dash/dash-renderer/src/components/error/FrontEnd/FrontEndError.react.js b/dash/dash-renderer/src/components/error/FrontEnd/FrontEndError.react.js
@@ -110,7 +110,7 @@ function UnconnectedErrorContent({error, base}) {
             )}
             {/* Backend Error */}
             {typeof error.html !== 'string' ? null : error.html.indexOf(
-                  '<!DOCTYPE HTML'
+                  '<!DOCTYPE'
               ) === 0 ? (
                 <div className='dash-be-error__st'>
                     <div className='dash-backend-error'>
diff --git a/dash/dash.py b/dash/dash.py
@@ -11,11 +11,12 @@
 import mimetypes
 import hashlib
 import base64
+import traceback
 from urllib.parse import urlparse
 
 import flask
 from flask_compress import Compress
-from werkzeug.debug.tbtools import get_current_traceback
+
 from pkg_resources import get_distribution, parse_version
 from dash import dcc
 from dash import html
@@ -48,6 +49,7 @@
     patch_collections_abc,
     split_callback_id,
     to_json,
+    gen_salt,
 )
 from . import _callback
 from . import _get_paths
@@ -102,6 +104,42 @@
 _re_renderer_scripts_id = 'id="_dash-renderer', "new DashRenderer"
 
 
+def _get_traceback(secret, error: Exception):
+
+    try:
+        # pylint: disable=import-outside-toplevel
+        from werkzeug.debug import tbtools
+    except ImportError:
+        tbtools = None
+
+    def _get_skip(text, divider=2):
+        skip = 0
+        for i, line in enumerate(text):
+            if "%% callback invoked %%" in line:
+                skip = int((i + 1) / divider)
+                break
+        return skip
+
+    # werkzeug<2.1.0
+    if hasattr(tbtools, "get_current_traceback"):
+        tb = tbtools.get_current_traceback()
+        skip = _get_skip(tb.plaintext.splitlines())
+        return tbtools.get_current_traceback(skip=skip).render_full()
+
+    if hasattr(tbtools, "DebugTraceback"):
+        tb = tbtools.DebugTraceback(error)  # pylint: disable=no-member
+        skip = _get_skip(tb.render_traceback_text().splitlines())
+
+        # pylint: disable=no-member
+        return tbtools.DebugTraceback(error, skip=skip).render_debugger_html(
+            True, secret, True
+        )
+
+    tb = traceback.format_exception(type(error), error, error.__traceback__)
+    skip = _get_skip(tb, 1)
+    return tb[0] + "".join(tb[skip:])
+
+
 class _NoUpdate:
     # pylint: disable=too-few-public-methods
     pass
@@ -1756,19 +1794,16 @@ def enable_dev_tools(
 
         if debug and dev_tools.prune_errors:
 
+            secret = gen_salt(20)
+
             @self.server.errorhandler(Exception)
-            def _wrap_errors(_):
+            def _wrap_errors(error):
                 # find the callback invocation, if the error is from a callback
                 # and skip the traceback up to that point
                 # if the error didn't come from inside a callback, we won't
                 # skip anything.
-                tb = get_current_traceback()
-                skip = 0
-                for i, line in enumerate(tb.plaintext.splitlines()):
-                    if "%% callback invoked %%" in line:
-                        skip = int((i + 1) / 2)
-                        break
-                return get_current_traceback(skip=skip).render_full(), 500
+                tb = _get_traceback(secret, error)
+                return tb, 500
 
         if debug and dev_tools.ui:
 
