gdb: re-format Python files using black 21.4b0

Re-format all Python files using black [1] version 21.4b0.  The goal is
that from now on, we keep all Python files formatted using black.  And
that we never have to discuss formatting during review (for these files
at least) ever again.

One change is needed in gdb.python/py-prettyprint.exp, because it
matches the string representation of an exception, which shows source
code.  So the change in formatting must be replicated in the expected
regexp.

To document our usage of black I plan on adding this to the "GDB Python
Coding Standards" wiki page [2]:

--8<--

All Python source files under the `gdb/` directory must be formatted
using black version 21.4b0.

This specific version can be installed using:

    $ pip3 install 'black == 21.4b0'

All you need to do to re-format files is run `black <file/directory>`,
and black will re-format any Python file it finds in there.  It runs
quite fast, so the simplest is to do:

    $ black gdb/

from the top-level.

If you notice that black produces changes unrelated to your patch, it's
probably because someone forgot to run it before you.  In this case,
don't include unrelated hunks in your patch.  Push an obvious patch
fixing the formatting and rebase your work on top of that.

-->8--

Once this is merged, I plan on setting a up an `ignoreRevsFile`
config so that git-blame ignores this commit, as described here:

  https://github.com/psf/black#migrating-your-code-style-without-ruining-git-blame

I also plan on working on a git commit hook (checked in the repo) to
automatically check the formatting of the Python files on commit.

[1] https://pypi.org/project/black/
[2] https://sourceware.org/gdb/wiki/Internals%20GDB-Python-Coding-Standards

gdb/ChangeLog:

	* Re-format all Python files using black.

gdb/testsuite/ChangeLog:

	* Re-format all Python files using black.
	* gdb.python/py-prettyprint.exp (run_lang_tests): Adjust.

Change-Id: I28588a22c2406afd6bc2703774ddfff47cd61919

1 files changed, 26 insertions, 23 deletions

diff --git a/gdb/testsuite/gdb.python/tui-window-disabled.py b/gdb/testsuite/gdb.python/tui-window-disabled.py
index 0b3c076f7e9..2510f13ca13 100644
--- a/gdb/testsuite/gdb.python/tui-window-disabled.py
+++ b/gdb/testsuite/gdb.python/tui-window-disabled.py
@@ -28,62 +28,65 @@ cleanup_properly = False
 # A global place into which we can write the window title.
 titles_at_the_close = {}
 
+
 class EventWindow:
-    def __init__ (self, win):
+    def __init__(self, win):
         self._win = win
         self._count = 0
         win.title = "This Is The Event Window"
-        self._stop_listener = lambda e : self._event ('stop', e)
-        gdb.events.stop.connect (self._stop_listener)
-        self._exit_listener = lambda e : self._event ('exit', e)
-        gdb.events.exited.connect (self._exit_listener)
+        self._stop_listener = lambda e: self._event("stop", e)
+        gdb.events.stop.connect(self._stop_listener)
+        self._exit_listener = lambda e: self._event("exit", e)
+        gdb.events.exited.connect(self._exit_listener)
         self._events = []
 
         # Ensure we can erase and write to the window from the
         # constructor, the window should be valid by this point.
-        self._win.erase ()
-        self._win.write ("Hello world...")
+        self._win.erase()
+        self._win.write("Hello world...")
 
-    def close (self):
+    def close(self):
         global cleanup_properly
         global titles_at_the_close
 
         # Ensure that window properties can be read within the close method.
-        titles_at_the_close[self._win.title] = dict (width=self._win.width,
-                                                     height=self._win.height)
+        titles_at_the_close[self._win.title] = dict(
+            width=self._win.width, height=self._win.height
+        )
 
         # The following calls are pretty pointless, but this ensures
         # that we can erase and write to a window from the close
         # method, the last moment a window should be valid.
-        self._win.erase ()
-        self._win.write ("Goodbye cruel world...")
+        self._win.erase()
+        self._win.write("Goodbye cruel world...")
 
         if cleanup_properly:
             # Disconnect the listeners and delete the lambda functions.
             # This removes cyclic references to SELF, and so alows SELF to
             # be deleted.
-            gdb.events.stop.disconnect (self._stop_listener)
-            gdb.events.exited.disconnect (self._exit_listener)
+            gdb.events.stop.disconnect(self._stop_listener)
+            gdb.events.exited.disconnect(self._exit_listener)
             self._stop_listener = None
             self._exit_listener = None
 
-    def _event (self, type, event):
+    def _event(self, type, event):
         global perform_valid_check
         global update_title
 
         self._count += 1
-        self._events.insert (0, type)
-        if not perform_valid_check or self._win.is_valid ():
+        self._events.insert(0, type)
+        if not perform_valid_check or self._win.is_valid():
             if update_title:
-                self._win.title = "This Is The Event Window (" + str (self._count) + ")"
+                self._win.title = "This Is The Event Window (" + str(self._count) + ")"
             else:
-                self.render ()
+                self.render()
 
-    def render (self):
-        self._win.erase ()
+    def render(self):
+        self._win.erase()
         w = self._win.width
         h = self._win.height
-        for i in range (min (h, len (self._events))):
-            self._win.write (self._events[i] + "\n")
+        for i in range(min(h, len(self._events))):
+            self._win.write(self._events[i] + "\n")
+
 
 gdb.register_window_type("events", EventWindow)