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, 38 insertions, 33 deletions

diff --git a/gdb/testsuite/gdb.python/py-nested-maps.py b/gdb/testsuite/gdb.python/py-nested-maps.py
index 9352bdd..163fc86 100644
--- a/gdb/testsuite/gdb.python/py-nested-maps.py
+++ b/gdb/testsuite/gdb.python/py-nested-maps.py
@@ -19,15 +19,17 @@
 import re
 import gdb
 
-def _iterator1 (pointer, len):
+
+def _iterator1(pointer, len):
     while len > 0:
         map = pointer.dereference()
-        yield ('', map['name'])
-        yield ('', map.dereference())
+        yield ("", map["name"])
+        yield ("", map.dereference())
         pointer += 1
         len -= 1
 
-def _iterator2 (pointer1, pointer2, len):
+
+def _iterator2(pointer1, pointer2, len):
     while len > 0:
         yield ("", pointer1.dereference())
         yield ("", pointer2.dereference())
@@ -35,42 +37,42 @@ def _iterator2 (pointer1, pointer2, len):
         pointer2 += 1
         len -= 1
 
-class pp_map (object):
+
+class pp_map(object):
     def __init__(self, val):
         self.val = val
 
     def to_string(self):
-        if (self.val['show_header'] == 0):
+        if self.val["show_header"] == 0:
             return None
         else:
             return "pp_map"
 
     def children(self):
-        return _iterator2(self.val['keys'],
-                          self.val['values'],
-                          self.val['length'])
+        return _iterator2(self.val["keys"], self.val["values"], self.val["length"])
+
+    def display_hint(self):
+        return "map"
 
-    def display_hint (self):
-        return 'map'
 
-class pp_map_map (object):
+class pp_map_map(object):
     def __init__(self, val):
         self.val = val
 
     def to_string(self):
-        if (self.val['show_header'] == 0):
+        if self.val["show_header"] == 0:
             return None
         else:
             return "pp_map_map"
 
     def children(self):
-        return _iterator1(self.val['values'],
-                          self.val['length'])
+        return _iterator1(self.val["values"], self.val["length"])
 
-    def display_hint (self):
-        return 'map'
+    def display_hint(self):
+        return "map"
 
-def lookup_function (val):
+
+def lookup_function(val):
     "Look-up and return a pretty-printer that can print val."
 
     # Get the type.
@@ -78,10 +80,10 @@ def lookup_function (val):
 
     # If it points to a reference, get the reference.
     if type.code == gdb.TYPE_CODE_REF:
-        type = type.target ()
+        type = type.target()
 
     # Get the unqualified type, stripped of typedefs.
-    type = type.unqualified ().strip_typedefs ()
+    type = type.unqualified().strip_typedefs()
 
     # Get the type name.
     typename = type.tag
@@ -93,14 +95,15 @@ def lookup_function (val):
     # if a printer is registered for that type.  Return an
     # instantiation of the printer if found.
     for function in pretty_printers_dict:
-        if function.match (typename):
-            return pretty_printers_dict[function] (val)
+        if function.match(typename):
+            return pretty_printers_dict[function](val)
 
     # Cannot find a pretty printer.  Return None.
     return None
 
+
 # Lookup a printer for VAL in the typedefs dict.
-def lookup_typedefs_function (val):
+def lookup_typedefs_function(val):
     "Look-up and return a pretty-printer that can print val (typedefs)."
 
     # Get the type.
@@ -113,23 +116,25 @@ def lookup_typedefs_function (val):
     # printer is registered for that type.  Return an instantiation of
     # the printer if found.
     for function in typedefs_pretty_printers_dict:
-        if function.match (type.name):
-            return typedefs_pretty_printers_dict[function] (val)
+        if function.match(type.name):
+            return typedefs_pretty_printers_dict[function](val)
 
     # Cannot find a pretty printer.
     return None
 
-def register_pretty_printers ():
-    pretty_printers_dict[re.compile ('^struct map_t$')] = pp_map
-    pretty_printers_dict[re.compile ('^map_t$')] = pp_map
-    pretty_printers_dict[re.compile ('^struct map_map_t$')] = pp_map_map
-    pretty_printers_dict[re.compile ('^map_map_t$')] = pp_map_map
+
+def register_pretty_printers():
+    pretty_printers_dict[re.compile("^struct map_t$")] = pp_map
+    pretty_printers_dict[re.compile("^map_t$")] = pp_map
+    pretty_printers_dict[re.compile("^struct map_map_t$")] = pp_map_map
+    pretty_printers_dict[re.compile("^map_map_t$")] = pp_map_map
+
 
 # Dict for struct types with typedefs fully stripped.
 pretty_printers_dict = {}
 # Dict for typedef types.
 typedefs_pretty_printers_dict = {}
 
-register_pretty_printers ()
-gdb.pretty_printers.append (lookup_function)
-gdb.pretty_printers.append (lookup_typedefs_function)
+register_pretty_printers()
+gdb.pretty_printers.append(lookup_function)
+gdb.pretty_printers.append(lookup_typedefs_function)