Add debug logging for type conversions

Author: ctrueden

src/scyjava/__init__.py

@@ -174,10 +174,15 @@ def __getattr__(name):
 
 
 def _initialize_converters():
+    _logger.debug("Initializing type converters")
+
     for converter in _stock_java_converters():
         add_java_converter(converter)
+    _logger.debug("Java converters:{'\n-'.join(java_converters)}")
+
     for converter in _stock_py_converters():
         add_py_converter(converter)
+    _logger.debug("Python converters:{'\n-'.join(py_converters)}")
 
 
 when_jvm_starts(_initialize_converters)

src/scyjava/_convert.py

@@ -4,6 +4,7 @@
 
 import collections
 import inspect
+import logging
 import math
 from bisect import insort
 from pathlib import Path
@@ -24,6 +25,8 @@
     start_jvm,
 )
 
+_logger = logging.getLogger(__name__)
+
 
 # NB: We cannot use org.scijava.priority.Priority or other Java-side class
 # here because we don't want to impose Java-side dependencies, and we don't
@@ -92,9 +95,14 @@ def _convert(obj: Any, converters: List[Converter], **hints: Dict) -> Any:
     # meaning lower-priority items appear earlier than higher-priority ones.
     # But we want to try the higher priority converters first, so we
     # need to iterate the given converters list starting at the end.
+    debug = hints.get("debug", False)
+    log = _logger.info if debug else _logger.debug
+    log(f"Converting object of type {type(obj)} with hints {hints}")
     for converter in reversed(converters):
         if converter.supports(obj, **hints):
+            log(f"- {converter} supports")
             return converter.convert(obj, **hints)
+        log(f"- {converter} does not support")
 
 
 # -- Python to Java --