SCons: Format buildsystem files with psf/black

Configured for a max line length of 120 characters.

psf/black is very opinionated and purposely doesn't leave much room for
configuration. The output is mostly OK so that should be fine for us,
but some things worth noting:

- Manually wrapped strings will be reflowed, so by using a line length
  of 120 for the sake of preserving readability for our long command
  calls, it also means that some manually wrapped strings are back on
  the same line and should be manually merged again.

- Code generators using string concatenation extensively look awful,
  since black puts each operand on a single line. We need to refactor
  these generators to use more pythonic string formatting, for which
  many options are available (`%`, `format` or f-strings).

- CI checks and a pre-commit hook will be added to ensure that future
  buildsystem changes are well-formatted.

1 files changed, 64 insertions, 42 deletions

diff --git a/doc/translations/extract.py b/doc/translations/extract.py
index cd06e13dda..a65f942b92 100644
--- a/doc/translations/extract.py
+++ b/doc/translations/extract.py
@@ -7,7 +7,7 @@ import shutil
 from collections import OrderedDict
 
 EXTRACT_TAGS = ["description", "brief_description", "member", "constant", "theme_item", "link"]
-HEADER = '''\
+HEADER = """\
 # LANGUAGE translation of the Godot Engine class reference.
 # Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.
 # Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).
@@ -24,7 +24,7 @@ msgstr ""
 "Content-Type: text/plain; charset=UTF-8\\n"
 "Content-Transfer-Encoding: 8-bit\\n"
 
-'''
+"""
 # Some strings used by makerst.py are normally part of the editor translations,
 # so we need to include them manually here for the online docs.
 BASE_STRINGS = [
@@ -42,7 +42,8 @@ BASE_STRINGS = [
 
 ## <xml-line-number-hack from="https://stackoverflow.com/a/36430270/10846399">
 import sys
-sys.modules['_elementtree'] = None
+
+sys.modules["_elementtree"] = None
 import xml.etree.ElementTree as ET
 
 ## override the parser to get the line number
@@ -62,8 +63,11 @@ class LineNumberingParser(ET.XMLParser):
         element._end_column_number = self.parser.CurrentColumnNumber
         element._end_byte_index = self.parser.CurrentByteIndex
         return element
+
+
 ## </xml-line-number-hack>
 
+
 class Desc:
     def __init__(self, line_no, msg, desc_list=None):
         ## line_no   : the line number where the desc is
@@ -73,6 +77,7 @@ class Desc:
         self.msg = msg
         self.desc_list = desc_list
 
+
 class DescList:
     def __init__(self, doc, path):
         ## doc  : root xml element of the document
@@ -82,29 +87,32 @@ class DescList:
         self.path = path
         self.list = []
 
+
 def print_error(error):
     print("ERROR: {}".format(error))
 
+
 ## build classes with xml elements recursively
 def _collect_classes_dir(path, classes):
     if not os.path.isdir(path):
         print_error("Invalid directory path: {}".format(path))
         exit(1)
-    for _dir in map(lambda dir : os.path.join(path, dir), os.listdir(path)):
+    for _dir in map(lambda dir: os.path.join(path, dir), os.listdir(path)):
         if os.path.isdir(_dir):
             _collect_classes_dir(_dir, classes)
         elif os.path.isfile(_dir):
             if not _dir.endswith(".xml"):
-                #print("Got non-.xml file '{}', skipping.".format(path))
+                # print("Got non-.xml file '{}', skipping.".format(path))
                 continue
             _collect_classes_file(_dir, classes)
 
+
 ## opens a file and parse xml add to classes
 def _collect_classes_file(path, classes):
     if not os.path.isfile(path) or not path.endswith(".xml"):
         print_error("Invalid xml file path: {}".format(path))
         exit(1)
-    print('Collecting file: {}'.format(os.path.basename(path)))
+    print("Collecting file: {}".format(os.path.basename(path)))
 
     try:
         tree = ET.parse(path, parser=LineNumberingParser())
@@ -114,8 +122,8 @@ def _collect_classes_file(path, classes):
 
     doc = tree.getroot()
 
-    if 'name' in doc.attrib:
-        if 'version' not in doc.attrib:
+    if "name" in doc.attrib:
+        if "version" not in doc.attrib:
             print_error("Version missing from 'doc', file: {}".format(path))
 
         name = doc.attrib["name"]
@@ -124,7 +132,7 @@ def _collect_classes_file(path, classes):
             exit(1)
         classes[name] = DescList(doc, path)
     else:
-        print_error('Unknown XML file {}, skipping'.format(path))
+        print_error("Unknown XML file {}, skipping".format(path))
 
 
 ## regions are list of tuples with size 3 (start_index, end_index, indent)
@@ -132,56 +140,64 @@ def _collect_classes_file(path, classes):
 ## if i inside the region returns the indent, else returns -1
 def _get_xml_indent(i, regions):
     for region in regions:
-        if region[0] < i < region[1] :
+        if region[0] < i < region[1]:
             return region[2]
     return -1
 
+
 ## find and build all regions of codeblock which we need later
-def _make_codeblock_regions(desc, path=''):
+def _make_codeblock_regions(desc, path=""):
     code_block_end = False
     code_block_index = 0
     code_block_regions = []
     while not code_block_end:
         code_block_index = desc.find("[codeblock]", code_block_index)
-        if code_block_index < 0: break
-        xml_indent=0
-        while True :
+        if code_block_index < 0:
+            break
+        xml_indent = 0
+        while True:
             ## [codeblock] always have a trailing new line and some tabs
             ## those tabs are belongs to xml indentations not code indent
-            if desc[code_block_index+len("[codeblock]\n")+xml_indent] == '\t':
-                xml_indent+=1
-            else: break
+            if desc[code_block_index + len("[codeblock]\n") + xml_indent] == "\t":
+                xml_indent += 1
+            else:
+                break
         end_index = desc.find("[/codeblock]", code_block_index)
-        if end_index < 0 :
-            print_error('Non terminating codeblock: {}'.format(path))
+        if end_index < 0:
+            print_error("Non terminating codeblock: {}".format(path))
             exit(1)
-        code_block_regions.append( (code_block_index, end_index, xml_indent) )
+        code_block_regions.append((code_block_index, end_index, xml_indent))
         code_block_index += 1
     return code_block_regions
 
+
 def _strip_and_split_desc(desc, code_block_regions):
-    desc_strip = ''   ## a stripped desc msg
+    desc_strip = ""  ## a stripped desc msg
     total_indent = 0  ## code indent = total indent - xml indent
     for i in range(len(desc)):
         c = desc[i]
-        if c == '\n' : c = '\\n'
-        if c == '"': c = '\\"'
-        if c == '\\': c = '\\\\' ## <element \> is invalid for msgmerge
-        if c == '\t':
+        if c == "\n":
+            c = "\\n"
+        if c == '"':
+            c = '\\"'
+        if c == "\\":
+            c = "\\\\"  ## <element \> is invalid for msgmerge
+        if c == "\t":
             xml_indent = _get_xml_indent(i, code_block_regions)
             if xml_indent >= 0:
                 total_indent += 1
                 if xml_indent < total_indent:
-                    c = '\\t'
+                    c = "\\t"
                 else:
                     continue
             else:
                 continue
         desc_strip += c
-        if c == '\\n':
+        if c == "\\n":
             total_indent = 0
     return desc_strip
 
+
 ## make catalog strings from xml elements
 def _make_translation_catalog(classes):
     unique_msgs = OrderedDict()
@@ -189,8 +205,9 @@ def _make_translation_catalog(classes):
         desc_list = classes[class_name]
         for elem in desc_list.doc.iter():
             if elem.tag in EXTRACT_TAGS:
-                if not elem.text or len(elem.text) == 0 : continue
-                line_no = elem._start_line_number if elem.text[0]!='\n' else elem._start_line_number+1
+                if not elem.text or len(elem.text) == 0:
+                    continue
+                line_no = elem._start_line_number if elem.text[0] != "\n" else elem._start_line_number + 1
                 desc_str = elem.text.strip()
                 code_block_regions = _make_codeblock_regions(desc_str, desc_list.path)
                 desc_msg = _strip_and_split_desc(desc_str, code_block_regions)
@@ -203,44 +220,48 @@ def _make_translation_catalog(classes):
                     unique_msgs[desc_msg].append(desc_obj)
     return unique_msgs
 
+
 ## generate the catalog file
 def _generate_translation_catalog_file(unique_msgs, output):
-    with open(output, 'w', encoding='utf8') as f:
+    with open(output, "w", encoding="utf8") as f:
         f.write(HEADER)
         for msg in BASE_STRINGS:
-            f.write('#: doc/tools/makerst.py\n')
+            f.write("#: doc/tools/makerst.py\n")
             f.write('msgid "{}"\n'.format(msg))
             f.write('msgstr ""\n\n')
         for msg in unique_msgs:
             if len(msg) == 0 or msg in BASE_STRINGS:
                 continue
 
-            f.write('#:')
+            f.write("#:")
             desc_list = unique_msgs[msg]
             for desc in desc_list:
-                path = desc.desc_list.path.replace('\\', '/')
-                if path.startswith('./'):
+                path = desc.desc_list.path.replace("\\", "/")
+                if path.startswith("./"):
                     path = path[2:]
-                f.write(' {}:{}'.format(path, desc.line_no))
-            f.write('\n')
+                f.write(" {}:{}".format(path, desc.line_no))
+            f.write("\n")
 
             f.write('msgid "{}"\n'.format(msg))
             f.write('msgstr ""\n\n')
 
     ## TODO: what if 'nt'?
-    if (os.name == "posix"):
+    if os.name == "posix":
         print("Wrapping template at 79 characters for compatibility with Weblate.")
         os.system("msgmerge -w79 {0} {0} > {0}.wrap".format(output))
         shutil.move("{}.wrap".format(output), output)
 
+
 def main():
     parser = argparse.ArgumentParser()
-    parser.add_argument("--path", "-p", nargs="+", default=".", help="The directory or directories containing XML files to collect.")
+    parser.add_argument(
+        "--path", "-p", nargs="+", default=".", help="The directory or directories containing XML files to collect."
+    )
     parser.add_argument("--output", "-o", default="translation_catalog.pot", help="The path to the output file.")
     args = parser.parse_args()
 
     output = os.path.abspath(args.output)
-    if not os.path.isdir(os.path.dirname(output)) or not output.endswith('.pot'):
+    if not os.path.isdir(os.path.dirname(output)) or not output.endswith(".pot"):
         print_error("Invalid output path: {}".format(output))
         exit(1)
 
@@ -252,13 +273,14 @@ def main():
 
         print("\nCurrent working dir: {}".format(path))
 
-        path_classes = OrderedDict() ## dictionary of key=class_name, value=DescList objects
+        path_classes = OrderedDict()  ## dictionary of key=class_name, value=DescList objects
         _collect_classes_dir(path, path_classes)
         classes.update(path_classes)
 
-    classes = OrderedDict(sorted(classes.items(), key = lambda kv: kv[0].lower()))
+    classes = OrderedDict(sorted(classes.items(), key=lambda kv: kv[0].lower()))
     unique_msgs = _make_translation_catalog(classes)
     _generate_translation_catalog_file(unique_msgs, output)
 
-if __name__ == '__main__':
+
+if __name__ == "__main__":
     main()