From d0e8ed7b1bb0771aabec9c11f74ff8af38bb1340 Mon Sep 17 00:00:00 2001
From: David Hotham <david.hotham@blueyonder.co.uk>
Date: Sun, 19 Jun 2022 16:27:55 +0100
Subject: [PATCH] Always show something when rendering exceptions

---
 cleo/ui/exception_trace.py       |  6 ++++--
 tests/ui/test_exception_trace.py | 31 +++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/cleo/ui/exception_trace.py b/cleo/ui/exception_trace.py
index 1e3f02da..eb7ed439 100644
--- a/cleo/ui/exception_trace.py
+++ b/cleo/ui/exception_trace.py
@@ -252,9 +252,11 @@ def ignore_files_in(self, ignore: str) -> ExceptionTrace:
         return self
 
     def render(self, io: IO | Output, simple: bool = False) -> None:
-        if simple:
+        # If simple rendering wouldn't show anything useful, abandon it.
+        simple_string = str(self._exception) if simple else ""
+        if simple_string:
             io.write_line("")
-            io.write_line(f"<error>{str(self._exception)}</error>")
+            io.write_line(f"<error>{simple_string}</error>")
         else:
             self._render_exception(io, self._exception)
 
diff --git a/tests/ui/test_exception_trace.py b/tests/ui/test_exception_trace.py
index e7731f1c..abd43e3a 100644
--- a/tests/ui/test_exception_trace.py
+++ b/tests/ui/test_exception_trace.py
@@ -408,3 +408,34 @@ def test_simple_render_supports_solutions():
     https://example2.com
 """
     assert io.fetch_output() == expected
+
+
+def test_simple_render_aborts_if_no_message():
+    io = BufferedIO()
+
+    with pytest.raises(Exception) as e:
+        raise AssertionError
+
+    trace = ExceptionTrace(e.value)
+
+    trace.render(io, simple=True)
+    lineno = 417
+
+    expected = f"""
+  AssertionError
+
+  
+
+  at {trace._get_relative_file_path(__file__)}:{lineno} in \
+test_simple_render_aborts_if_no_message
+      {lineno - 4}│ def test_simple_render_aborts_if_no_message():
+      {lineno - 3}│     io = BufferedIO()
+      {lineno - 2}│ 
+      {lineno - 1}│     with pytest.raises(Exception) as e:
+    → {lineno + 0}│         raise AssertionError
+      {lineno + 1}│ 
+      {lineno + 2}│     trace = ExceptionTrace(e.value)
+      {lineno + 3}│ 
+      {lineno + 4}│     trace.render(io, simple=True)
+"""  # noqa: W293
+    assert expected == io.fetch_output()