wip

loguru/_better_exceptions.py

@@ -10,6 +10,16 @@
 import tokenize
 import traceback
 
+if sys.version_info >= (3, 11):
+
+    def is_exception_group(exc):
+        return isinstance(exc, ExceptionGroup)
+
+else:
+
+    def is_exception_group(exc):
+        return False
+
 
 class SyntaxHighlighter:
     _default_style = {
@@ -344,7 +354,9 @@ def _format_locations(self, frames_lines, *, has_introduction):
 
             yield frame
 
-    def _format_exception(self, value, tb, *, seen=None, is_first=False, from_decorator=False):
+    def _format_exception(
+        self, value, tb, *, seen=None, is_first=False, from_decorator=False, group_nesting=0
+    ):
         # Implemented from built-in traceback module:
         # https://github.com/python/cpython/blob/a5b76167/Lib/traceback.py#L468
         exc_type, exc_value, exc_traceback = type(value), value, tb
@@ -354,36 +366,50 @@ def _format_exception(self, value, tb, *, seen=None, is_first=False, from_decora
 
         seen.add(id(exc_value))
 
+        def indent(text):
+            if group_nesting == 0:
+                yield text
+                return
+            for line in text.splitlines(True):
+                indented = "  " * group_nesting + "| " + line
+                yield indented.rstrip() + "\n"
+
         if exc_value:
             if exc_value.__cause__ is not None and id(exc_value.__cause__) not in seen:
                 for text in self._format_exception(
-                    exc_value.__cause__, exc_value.__cause__.__traceback__, seen=seen
+                    exc_value.__cause__,
+                    exc_value.__cause__.__traceback__,
+                    seen=seen,
+                    group_nesting=group_nesting,
                 ):
                     yield text
                 cause = "The above exception was the direct cause of the following exception:"
                 if self._colorize:
                     cause = self._theme["cause"].format(cause)
                 if self._diagnose:
-                    yield "\n\n" + cause + "\n\n\n"
+                    yield from indent("\n\n" + cause + "\n\n\n")
                 else:
-                    yield "\n" + cause + "\n\n"
+                    yield from indent("\n" + cause + "\n\n")
 
             elif (
                 exc_value.__context__ is not None
                 and id(exc_value.__context__) not in seen
                 and not exc_value.__suppress_context__
             ):
                 for text in self._format_exception(
-                    exc_value.__context__, exc_value.__context__.__traceback__, seen=seen
+                    exc_value.__context__,
+                    exc_value.__context__.__traceback__,
+                    seen=seen,
+                    group_nesting=group_nesting,
                 ):
                     yield text
                 context = "During handling of the above exception, another exception occurred:"
                 if self._colorize:
                     context = self._theme["context"].format(context)
                 if self._diagnose:
-                    yield "\n\n" + context + "\n\n\n"
+                    yield from indent("\n\n" + context + "\n\n\n")
                 else:
-                    yield "\n" + context + "\n\n"
+                    yield from indent("\n" + context + "\n\n")
 
         try:
             tracebacklimit = sys.tracebacklimit
@@ -426,12 +452,46 @@ def _format_exception(self, value, tb, *, seen=None, is_first=False, from_decora
             yield self._prefix
 
         if has_introduction:
-            introduction = "Traceback (most recent call last):"
+            if is_exception_group(value):
+                introduction = "Exception Group Traceback (most recent call last):"
+            else:
+                introduction = "Traceback (most recent call last):"
             if self._colorize:
                 introduction = self._theme["introduction"].format(introduction)
-            yield introduction + "\n"
+            if is_exception_group(value) and group_nesting == 0:
+                yield "  + " + introduction + "\n"
+            else:
+                yield from indent(introduction + "\n")
+
+        if is_exception_group(value) and group_nesting == 0:
+            group_nesting = 1
 
-        yield "".join(frames_lines)
+        if group_nesting <= 10 or not is_exception_group(value):
+            yield from indent("".join(frames_lines))
+
+        if is_exception_group(value):
+            if group_nesting > 10:
+                yield "  " * (group_nesting) + "| ... (max_group_depth is 10)\n"
+            else:
+                for n, exc in enumerate(value.exceptions, start=1):
+                    pref = "+-+" if n == 1 else "  +"
+                    if n > 15:
+                        yield "  " * (group_nesting) + pref + " ... ".center(35, "-") + "\n"
+                        yield "  " * (group_nesting) + "  | and %d more exceptions\n" % (
+                            len(value.exceptions) - 15
+                        )
+                        break
+                    yield "  " * (group_nesting) + pref + (" %d " % n).center(35, "-") + "\n"
+                    lines = self._format_exception(
+                        exc,
+                        exc.__traceback__,
+                        seen=seen,
+                        group_nesting=group_nesting + 1,
+                    )
+                    yield "".join(lines)
+
+                if not is_exception_group(exc) or group_nesting == 10:
+                    yield "  " * (group_nesting + 1) + "+------------------------------------\n"
 
     def format_exception(self, type_, value, tb, *, from_decorator=False):
         yield from self._format_exception(value, tb, is_first=True, from_decorator=from_decorator)