More stable exception handling in the completer.

news/completer_exception.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* More stable exception handling in the tab completer.
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

xonsh/completer.py

@@ -2,6 +2,7 @@
 """A (tab-)completer for xonsh."""
 import builtins
 import collections.abc as cabc
+from xonsh.tools import print_exception
 
 
 class Completer(object):
@@ -36,6 +37,13 @@ class Completer(object):
                 out = func(prefix, line, begidx, endidx, ctx)
             except StopIteration:
                 return set(), len(prefix)
+            except Exception as e:
+                print_exception(
+                    f"Completer {func.__name__} raises exception when get "
+                    f"(prefix={repr(prefix)}, line={repr(line)}, begidx={repr(begidx)}, endidx={repr(endidx)}):\n"
+                    f"{e}"
+                )
+                return set(), len(prefix)
             if isinstance(out, cabc.Sequence):
                 res, lprefix = out
             else: