From 0322982875c03d9b44ba3e5ef38863f26d8eef01 Mon Sep 17 00:00:00 2001
From: Alex Hall <alex.mojaki@gmail.com>
Date: Sun, 28 Apr 2019 12:56:57 +0200
Subject: [PATCH] More informative repr for exceptions. Forgot to use
 repr_instance

---
 pysnooper/tracer.py     | 27 ++++++++++++++++++++++++---
 tests/test_pysnooper.py | 27 +++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/pysnooper/tracer.py b/pysnooper/tracer.py
index bd0ec77..87e9ffa 100644
--- a/pysnooper/tracer.py
+++ b/pysnooper/tracer.py
@@ -15,12 +15,33 @@ from .third_party import six
 
 ipython_filename_pattern = re.compile('^<ipython-input-([0-9]+)-.*>$')
 
-repr_instance = reprlib.Repr()
-repr_instance.maxother = 100
+
+class MyRepr(reprlib.Repr):
+    def __init__(self):
+        super(MyRepr, self).__init__()
+        self.maxother = 100
+
+    def repr(self, x):
+        try:
+            return super(MyRepr, self).repr(x)
+        except Exception as e:
+            return '<{} instance at {:#x} (__repr__ raised {})>'.format(
+                x.__class__.__name__, id(x), e.__class__.__name__)
+
+    def repr_instance(self, x, level):
+        s = reprlib.builtins.repr(x)
+        if len(s) > self.maxother:
+            i = max(0, (self.maxother - 3) // 2)
+            j = max(0, self.maxother - 3 - i)
+            s = s[:i] + '...' + s[len(s) - j:]
+        return s
+
+
+repr_instance = MyRepr()
 
 
 def get_shortish_repr(item):
-    r = reprlib.repr(item)
+    r = repr_instance.repr(item)
     r = r.replace('\r', '').replace('\n', '')
     return r
 
diff --git a/tests/test_pysnooper.py b/tests/test_pysnooper.py
index 8f25373..03567c5 100644
--- a/tests/test_pysnooper.py
+++ b/tests/test_pysnooper.py
@@ -158,6 +158,33 @@ def test_long_variable():
     )
 
 
+def test_repr_exception():
+    class Bad(object):
+        def __repr__(self):
+            1 / 0
+
+    @pysnooper.snoop()
+    def my_function():
+        bad = Bad()
+
+    with sys_tools.OutputCapturer(stdout=False,
+                                  stderr=True) as output_capturer:
+        result = my_function()
+    assert result is None
+    output = output_capturer.string_io.getvalue()
+    assert_output(
+        output,
+        (
+            VariableEntry('Bad'),
+            CallEntry('def my_function():'),
+            LineEntry('bad = Bad()'),
+            VariableEntry('bad', value_regex=r'<Bad instance at 0x\w+ \(__repr__ raised ZeroDivisionError\)>'),
+            ReturnEntry(),
+            ReturnValueEntry('None')
+        )
+    )
+
+
 def test_depth():
     string_io = io.StringIO()