Remove process-wide sys.excepthook; harden log formatter (#1516)

src/datajoint/logging.py

@@ -28,11 +28,22 @@ class LevelAwareFormatter(logging.Formatter):
     def format(self, record):
         timestamp = self.formatTime(record, "%Y-%m-%d %H:%M:%S")
         if record.levelno >= logging.WARNING:
-            return f"[{timestamp}][{record.levelname}]: {record.getMessage()}"
+            message = f"[{timestamp}][{record.levelname}]: {record.getMessage()}"
         elif record.levelno == JOBS:
-            return f"[{timestamp}][JOBS]: {record.getMessage()}"
+            message = f"[{timestamp}][JOBS]: {record.getMessage()}"
         else:
-            return f"[{timestamp}] {record.getMessage()}"
+            message = f"[{timestamp}] {record.getMessage()}"
+
+        # Render exception/stack info like the base logging.Formatter does, so
+        # that a logger.exception(...)/exc_info=... call never silently drops
+        # the traceback (see #1516).
+        if record.exc_info and not record.exc_text:
+            record.exc_text = self.formatException(record.exc_info)
+        if record.exc_text:
+            message = f"{message}\n{record.exc_text}"
+        if record.stack_info:
+            message = f"{message}\n{self.formatStack(record.stack_info)}"
+        return message
 
 
 # Select output stream: stdout (default, no red highlighting) or stderr
@@ -44,13 +55,7 @@ def format(self, record):
 logger.setLevel(level=log_level)
 logger.handlers = [stream_handler]
 
-
-def excepthook(exc_type, exc_value, exc_traceback):
-    if issubclass(exc_type, KeyboardInterrupt):
-        sys.__excepthook__(exc_type, exc_value, exc_traceback)
-        return
-
-    logger.error("Uncaught exception", exc_info=(exc_type, exc_value, exc_traceback))
-
-
-sys.excepthook = excepthook
+# NOTE: DataJoint intentionally does NOT install a process-wide sys.excepthook.
+# Importing a library must not change how *unrelated* uncaught exceptions are
+# reported in the host process. Uncaught exceptions are left to Python's default
+# handler, which prints the full type/message/traceback to stderr. (See #1516.)

tests/unit/test_logging.py

@@ -0,0 +1,70 @@
+"""
+Tests for datajoint.logging.
+
+Regression coverage for #1516: importing datajoint must not install a
+process-wide sys.excepthook, and LevelAwareFormatter must not discard
+exc_info/stack_info.
+"""
+
+import logging
+import sys
+
+
+def test_import_does_not_replace_excepthook():
+    """Importing datajoint must leave sys.excepthook untouched (#1516)."""
+    original = sys.excepthook
+    try:
+        modules_to_remove = [key for key in sys.modules if key.startswith("datajoint")]
+        for mod in modules_to_remove:
+            del sys.modules[mod]
+
+        import datajoint  # noqa: F401
+
+        assert sys.excepthook is original, "importing datajoint replaced sys.excepthook"
+    finally:
+        sys.excepthook = original
+
+
+def test_formatter_renders_exception_info():
+    """LevelAwareFormatter must append the traceback when exc_info is set (#1516)."""
+    from datajoint.logging import LevelAwareFormatter
+
+    formatter = LevelAwareFormatter()
+    try:
+        raise ValueError("something specific and diagnosable went wrong")
+    except ValueError:
+        record = logging.LogRecord(
+            name="datajoint",
+            level=logging.ERROR,
+            pathname=__file__,
+            lineno=0,
+            msg="Uncaught exception",
+            args=(),
+            exc_info=sys.exc_info(),
+        )
+
+    output = formatter.format(record)
+    assert "Uncaught exception" in output
+    assert "ValueError: something specific and diagnosable went wrong" in output
+    assert "Traceback (most recent call last)" in output
+
+
+def test_formatter_renders_stack_info():
+    """LevelAwareFormatter must append stack_info when present (#1516)."""
+    from datajoint.logging import LevelAwareFormatter
+
+    formatter = LevelAwareFormatter()
+    record = logging.LogRecord(
+        name="datajoint",
+        level=logging.WARNING,
+        pathname=__file__,
+        lineno=0,
+        msg="with stack",
+        args=(),
+        exc_info=None,
+        sinfo="Stack (most recent call last):\n  fake stack frame",
+    )
+
+    output = formatter.format(record)
+    assert "with stack" in output
+    assert "fake stack frame" in output