debug: add 'pybehave' debug information

It shows the behavior flags from coverage.env.

Author: nedbat

CHANGES.rst

@@ -20,7 +20,7 @@ development at the same time, such as 4.5.x and 5.0.
 Unreleased
 ----------
 
-Nothing yet.
+- Debug: added ``pybehave`` to the list of :ref:`cmd_run_debug` options.
 
 
 .. _changes_631:

coverage/control.py

@@ -329,6 +329,19 @@ def _write_startup_debug(self):
                     write_formatted_info(self._debug, header, info)
                 wrote_any = True
 
+            if self._debug.should('pybehave'):
+                info = [
+                    (name, value) for name, value in env.__dict__.items()
+                    if not name.startswith("_") and
+                        name != "PYBEHAVIOR" and
+                        not isinstance(value, type(os))
+                ] + [
+                    (name, value) for name, value in env.PYBEHAVIOR.__dict__.items()
+                    if not name.startswith("_")
+                ]
+                write_formatted_info(self._debug, "pybehave", sorted(info))
+                wrote_any = True
+
         if wrote_any:
             write_formatted_info(self._debug, "end", ())
 

coverage/debug.py

@@ -118,7 +118,10 @@ def info_formatter(info):
     for label, data in info:
         if data == []:
             data = "-none-"
-        if isinstance(data, (list, set, tuple)):
+        if isinstance(data, tuple) and len(repr(tuple(data))) < 30:
+            # Convert to tuple to scrub namedtuples.
+            yield "%*s: %r" % (label_len, label, tuple(data))
+        elif isinstance(data, (list, set, tuple)):
             prefix = "%*s:" % (label_len, label)
             for e in data:
                 yield "%*s %s" % (label_len+1, prefix, e)
@@ -128,7 +131,13 @@ def info_formatter(info):
 
 
 def write_formatted_info(writer, header, info):
-    """Write a sequence of (label,data) pairs nicely."""
+    """Write a sequence of (label,data) pairs nicely.
+
+    `writer` has a .write(str) method. `header` is a string to start the
+    section.  `info` is a sequence of (label, data) pairs, where label
+    is a str, and data can be a single value, or a list/set/tuple.
+
+    """
     writer.write(info_header(header))
     for line in info_formatter(info):
         writer.write(" %s" % line)

doc/cmd.rst

@@ -981,6 +981,9 @@ of operation to log:
 * ``process``: show process creation information, and changes in the current
   directory.
 
+* ``pybehave``: show the values of `internal flags <env.py_>`_ describing the
+  behavior of the current version of Python.
+
 * ``self``: annotate each debug message with the object printing the message.
 
 * ``sql``: log the SQL statements used for recording data.
@@ -991,6 +994,8 @@ of operation to log:
 * ``trace``: print every decision about whether to trace a file or not. For
   files not being traced, the reason is also given.
 
+.. _env.py: https://github.com/nedbat/coveragepy/blob/master/coverage/env.py
+
 Debug options can also be set with the ``COVERAGE_DEBUG`` environment variable,
 a comma-separated list of these options.