From af6548a4e7a78d7a5a2f1b5fb3a3e056b14ba593 Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Sat, 23 May 2020 12:09:42 -0700
Subject: [PATCH] Merge pull request #7244 from DahlitzFlorian/fix-issue-7150

Prevent hiding underlying exception when ConfTestImportFailure is raised

(cherry picked from commit 45f53266e6fa1539b702df315847cfbce3e3f19e)
---
 changelog/7150.bugfix.rst | 1 +
 src/_pytest/debugging.py  | 5 +++++
 testing/test_debugging.py | 9 +++++++++
 3 files changed, 15 insertions(+)
 create mode 100644 changelog/7150.bugfix.rst

diff --git a/changelog/7150.bugfix.rst b/changelog/7150.bugfix.rst
new file mode 100644
index 00000000000..42cf5c7d2b9
--- /dev/null
+++ b/changelog/7150.bugfix.rst
@@ -0,0 +1 @@
+Prevent hiding the underlying exception when ``ConfTestImportFailure`` is raised.
diff --git a/src/_pytest/debugging.py b/src/_pytest/debugging.py
index 17915db73fc..26c3095dccd 100644
--- a/src/_pytest/debugging.py
+++ b/src/_pytest/debugging.py
@@ -4,6 +4,7 @@
 import sys
 
 from _pytest import outcomes
+from _pytest.config import ConftestImportFailure
 from _pytest.config import hookimpl
 from _pytest.config.exceptions import UsageError
 
@@ -338,6 +339,10 @@ def _postmortem_traceback(excinfo):
         # A doctest.UnexpectedException is not useful for post_mortem.
         # Use the underlying exception instead:
         return excinfo.value.exc_info[2]
+    elif isinstance(excinfo.value, ConftestImportFailure):
+        # A config.ConftestImportFailure is not useful for post_mortem.
+        # Use the underlying exception instead:
+        return excinfo.value.excinfo[2]
     else:
         return excinfo._excinfo[2]
 
diff --git a/testing/test_debugging.py b/testing/test_debugging.py
index 719d6477bff..00af4a088a7 100644
--- a/testing/test_debugging.py
+++ b/testing/test_debugging.py
@@ -342,6 +342,15 @@ def pytest_runtest_protocol():
         child.sendeof()
         self.flush(child)
 
+    def test_pdb_prevent_ConftestImportFailure_hiding_exception(self, testdir):
+        testdir.makepyfile("def test_func(): pass")
+        sub_dir = testdir.tmpdir.join("ns").ensure_dir()
+        sub_dir.join("conftest").new(ext=".py").write("import unknown")
+        sub_dir.join("test_file").new(ext=".py").write("def test_func(): pass")
+
+        result = testdir.runpytest_subprocess("--pdb", ".")
+        result.stdout.fnmatch_lines(["-> import unknown"])
+
     def test_pdb_interaction_capturing_simple(self, testdir):
         p1 = testdir.makepyfile(
             """