Nicer debug printing of functions.

qutebrowser/commands/cmdutils.py

@@ -27,7 +27,7 @@ import enum
 import inspect
 import collections
 
-from qutebrowser.utils import usertypes, qtutils, log
+from qutebrowser.utils import usertypes, qtutils, log, debug
 from qutebrowser.commands import command, cmdexc, argparser
 
 cmd_dict = {}
@@ -236,9 +236,10 @@ class register:  # pylint: disable=invalid-name
                 is_flag = typ == bool
                 args += self._get_argparse_args(param, annotation_info,
                                                 is_flag)
-                log.commands.vdebug('Adding argument {} of type {} -> '
-                                    'args {}, kwargs {}'.format(
-                                        param.name, typ, args, kwargs))
+                callsig = debug.format_call(parser.add_argument, args,
+                                            kwargs, full=False)
+                log.commands.vdebug('Adding arg {} of type {} -> {}'.format(
+                    param.name, typ, callsig))
                 parser.add_argument(*args, **kwargs)
         return has_count, desc, parser
 

qutebrowser/commands/command.py

@@ -23,7 +23,7 @@ from PyQt5.QtCore import QCoreApplication
 from PyQt5.QtWebKit import QWebSettings
 
 from qutebrowser.commands import cmdexc, argparser
-from qutebrowser.utils import log, utils, message
+from qutebrowser.utils import log, utils, message, debug
 
 
 class Command:
@@ -138,6 +138,6 @@ class Command:
             kwargs = {'count': count}
 
         self._check_prerequisites()
-        log.commands.debug('posargs: {}'.format(posargs))
-        log.commands.debug('kwargs: {}'.format(kwargs))
+        log.commands.debug('Calling {}'.format(
+            debug.format_call(self.handler, posargs, kwargs)))
         self.handler(*posargs, **kwargs)

qutebrowser/utils/debug.py

@@ -208,6 +208,18 @@ def signal_name(sig):
     return m.group(1)
 
 
+def _format_args(args=None, kwargs=None):
+    """Format a list of arguments/kwargs to a function-call like string."""
+    if args is not None:
+        arglist = [utils.compact_text(repr(arg), 50) for arg in args]
+    else:
+        arglist = []
+    if kwargs is not None:
+        for k, v in kwargs.items():
+            arglist.append('{}={}'.format(k, utils.compact_text(repr(v), 50)))
+    return ', '.join(arglist)
+
+
 def dbg_signal(sig, args):
     """Get a string representation of a signal for debugging.
 
@@ -218,6 +230,26 @@ def dbg_signal(sig, args):
     Return:
         A human-readable string representation of signal/args.
     """
-    argstr = ', '.join([utils.elide(str(a).replace('\n', ' '), 20)
-                        for a in args])
-    return '{}({})'.format(signal_name(sig), argstr)
+    return '{}({})'.format(signal_name(sig), _format_args(args))
+
+
+def format_call(func, args=None, kwargs=None, full=True):
+    """Get a string representation of a function calls with the given args.
+
+    Args:
+        func: The callable to print.
+        args: A list of positional arguments.
+        kwargs: A dict of named arguments.
+        full: Whether to print the full name
+
+    Return:
+        A string with the function call.
+    """
+    if full:
+        if func.__module__ is not None:
+            name = '.'.join([func.__module__, func.__qualname__])
+        else:
+            name = func.__qualname__
+    else:
+        name = func.__name__
+    return '{}({})'.format(name, _format_args(args, kwargs))

qutebrowser/utils/utilcmds.py

@@ -19,10 +19,14 @@
 
 """Misc. utility commands exposed to the user."""
 
+
+from PyQt5.QtCore import pyqtRemoveInputHook, QCoreApplication
+
 from functools import partial
 
-from qutebrowser.utils import usertypes
+from qutebrowser.utils import usertypes, log
 from qutebrowser.commands import runners, cmdexc, cmdutils
+from qutebrowser.config import config, style
 
 
 _timers = []
@@ -57,3 +61,65 @@ def later(ms : int, *command : {'nargs': '+'}):
     timer.timeout.connect(partial(_commandrunner.run_safely, cmdline))
     timer.timeout.connect(lambda: _timers.remove(timer))
     timer.start()
+
+
+@cmdutils.register(debug=True, name='debug-set-trace')
+def set_trace():
+    """Break into the debugger in the shell.
+
+    //
+
+    Based on http://stackoverflow.com/a/1745965/2085149
+    """
+    if sys.stdout is not None:
+        sys.stdout.flush()
+    print()
+    print("When done debugging, remember to execute:")
+    print("  from PyQt5 import QtCore; QtCore.pyqtRestoreInputHook()")
+    print("before executing c(ontinue).")
+    pyqtRemoveInputHook()
+    pdb.set_trace()
+
+
+@cmdutils.register(debug=True)
+def debug_crash(typ : ('exception', 'segfault') = 'exception'):
+    """Crash for debugging purposes.
+
+    Args:
+        typ: either 'exception' or 'segfault'.
+
+    Raises:
+        raises Exception when typ is not segfault.
+        segfaults when typ is (you don't say...)
+    """
+    if typ == 'segfault':
+        # From python's Lib/test/crashers/bogus_code_obj.py
+        co = types.CodeType(0, 0, 0, 0, 0, b'\x04\x71\x00\x00', (), (), (),
+                            '', '', 1, b'')
+        exec(co)  # pylint: disable=exec-used
+        raise Exception("Segfault failed (wat.)")
+    else:
+        raise Exception("Forced crash")
+
+
+@cmdutils.register(debug=True)
+def debug_all_widgets():
+    """Print a list of all widgets to debug log."""
+    s = QCoreApplication.instance().get_all_widgets()
+    log.misc.debug(s)
+
+
+@cmdutils.register(debug=True)
+def debug_all_objects():
+    """Print a list of  all objects to the debug log."""
+    s = QCoreApplication.instance().get_all_objects()
+    log.misc.debug(s)
+
+
+@cmdutils.register(debug=True)
+def debug_cache_stats():
+    """Print LRU cache stats."""
+    config_info = config.instance().get.cache_info()
+    style_info = style.get_stylesheet.cache_info()
+    log.misc.debug('config: {}'.format(config_info))
+    log.misc.debug('style: {}'.format(style_info))