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, 68 insertions, 46 deletions

diff --git a/doc/tools/doc_merge.py b/doc/tools/doc_merge.py
index 496d5dcb74..f6f52f5d66 100755
--- a/doc/tools/doc_merge.py
+++ b/doc/tools/doc_merge.py
@@ -21,7 +21,7 @@ def write_string(_f, text, newline=True):
     for t in range(tab):
         _f.write("\t")
     _f.write(text)
-    if (newline):
+    if newline:
         _f.write("\n")
 
 
@@ -30,7 +30,7 @@ def escape(ret):
     ret = ret.replace("<", "&gt;")
     ret = ret.replace(">", "&lt;")
     ret = ret.replace("'", "&apos;")
-    ret = ret.replace("\"", "&quot;")
+    ret = ret.replace('"', "&quot;")
     return ret
 
 
@@ -43,25 +43,26 @@ def dec_tab():
     global tab
     tab -= 1
 
+
 write_string(f, '<?xml version="1.0" encoding="UTF-8" ?>')
 write_string(f, '<doc version="' + new_doc.attrib["version"] + '">')
 
 
 def get_tag(node, name):
     tag = ""
-    if (name in node.attrib):
-        tag = ' ' + name + '="' + escape(node.attrib[name]) + '" '
+    if name in node.attrib:
+        tag = " " + name + '="' + escape(node.attrib[name]) + '" '
     return tag
 
 
 def find_method_descr(old_class, name):
 
     methods = old_class.find("methods")
-    if(methods != None and len(list(methods)) > 0):
+    if methods != None and len(list(methods)) > 0:
         for m in list(methods):
-            if (m.attrib["name"] == name):
+            if m.attrib["name"] == name:
                 description = m.find("description")
-                if (description != None and description.text.strip() != ""):
+                if description != None and description.text.strip() != "":
                     return description.text
 
     return None
@@ -70,11 +71,11 @@ def find_method_descr(old_class, name):
 def find_signal_descr(old_class, name):
 
     signals = old_class.find("signals")
-    if(signals != None and len(list(signals)) > 0):
+    if signals != None and len(list(signals)) > 0:
         for m in list(signals):
-            if (m.attrib["name"] == name):
+            if m.attrib["name"] == name:
                 description = m.find("description")
-                if (description != None and description.text.strip() != ""):
+                if description != None and description.text.strip() != "":
                     return description.text
 
     return None
@@ -82,13 +83,13 @@ def find_signal_descr(old_class, name):
 
 def find_constant_descr(old_class, name):
 
-    if (old_class is None):
+    if old_class is None:
         return None
     constants = old_class.find("constants")
-    if(constants != None and len(list(constants)) > 0):
+    if constants != None and len(list(constants)) > 0:
         for m in list(constants):
-            if (m.attrib["name"] == name):
-                if (m.text.strip() != ""):
+            if m.attrib["name"] == name:
+                if m.text.strip() != "":
                     return m.text
     return None
 
@@ -96,35 +97,35 @@ def find_constant_descr(old_class, name):
 def write_class(c):
     class_name = c.attrib["name"]
     print("Parsing Class: " + class_name)
-    if (class_name in old_classes):
+    if class_name in old_classes:
         old_class = old_classes[class_name]
     else:
         old_class = None
 
     category = get_tag(c, "category")
     inherits = get_tag(c, "inherits")
-    write_string(f, '<class name="' + class_name + '" ' + category + inherits + '>')
+    write_string(f, '<class name="' + class_name + '" ' + category + inherits + ">")
     inc_tab()
 
     write_string(f, "<brief_description>")
 
-    if (old_class != None):
+    if old_class != None:
         old_brief_descr = old_class.find("brief_description")
-        if (old_brief_descr != None):
+        if old_brief_descr != None:
             write_string(f, escape(old_brief_descr.text.strip()))
 
     write_string(f, "</brief_description>")
 
     write_string(f, "<description>")
-    if (old_class != None):
+    if old_class != None:
         old_descr = old_class.find("description")
-        if (old_descr != None):
+        if old_descr != None:
             write_string(f, escape(old_descr.text.strip()))
 
     write_string(f, "</description>")
 
     methods = c.find("methods")
-    if(methods != None and len(list(methods)) > 0):
+    if methods != None and len(list(methods)) > 0:
 
         write_string(f, "<methods>")
         inc_tab()
@@ -132,35 +133,46 @@ def write_class(c):
         for m in list(methods):
             qualifiers = get_tag(m, "qualifiers")
 
-            write_string(f, '<method name="' + escape(m.attrib["name"]) + '" ' + qualifiers + '>')
+            write_string(f, '<method name="' + escape(m.attrib["name"]) + '" ' + qualifiers + ">")
             inc_tab()
 
             for a in list(m):
-                if (a.tag == "return"):
+                if a.tag == "return":
                     typ = get_tag(a, "type")
-                    write_string(f, '<return' + typ + '>')
-                    write_string(f, '</return>')
-                elif (a.tag == "argument"):
+                    write_string(f, "<return" + typ + ">")
+                    write_string(f, "</return>")
+                elif a.tag == "argument":
 
                     default = get_tag(a, "default")
 
-                    write_string(f, '<argument index="' + a.attrib["index"] + '" name="' + escape(a.attrib["name"]) + '" type="' + a.attrib["type"] + '"' + default + '>')
-                    write_string(f, '</argument>')
-
-            write_string(f, '<description>')
-            if (old_class != None):
+                    write_string(
+                        f,
+                        '<argument index="'
+                        + a.attrib["index"]
+                        + '" name="'
+                        + escape(a.attrib["name"])
+                        + '" type="'
+                        + a.attrib["type"]
+                        + '"'
+                        + default
+                        + ">",
+                    )
+                    write_string(f, "</argument>")
+
+            write_string(f, "<description>")
+            if old_class != None:
                 old_method_descr = find_method_descr(old_class, m.attrib["name"])
-                if (old_method_descr):
+                if old_method_descr:
                     write_string(f, escape(escape(old_method_descr.strip())))
 
-            write_string(f, '</description>')
+            write_string(f, "</description>")
             dec_tab()
             write_string(f, "</method>")
         dec_tab()
         write_string(f, "</methods>")
 
     signals = c.find("signals")
-    if(signals != None and len(list(signals)) > 0):
+    if signals != None and len(list(signals)) > 0:
 
         write_string(f, "<signals>")
         inc_tab()
@@ -171,24 +183,33 @@ def write_class(c):
             inc_tab()
 
             for a in list(m):
-                if (a.tag == "argument"):
-
-                    write_string(f, '<argument index="' + a.attrib["index"] + '" name="' + escape(a.attrib["name"]) + '" type="' + a.attrib["type"] + '">')
-                    write_string(f, '</argument>')
-
-            write_string(f, '<description>')
-            if (old_class != None):
+                if a.tag == "argument":
+
+                    write_string(
+                        f,
+                        '<argument index="'
+                        + a.attrib["index"]
+                        + '" name="'
+                        + escape(a.attrib["name"])
+                        + '" type="'
+                        + a.attrib["type"]
+                        + '">',
+                    )
+                    write_string(f, "</argument>")
+
+            write_string(f, "<description>")
+            if old_class != None:
                 old_signal_descr = find_signal_descr(old_class, m.attrib["name"])
-                if (old_signal_descr):
+                if old_signal_descr:
                     write_string(f, escape(old_signal_descr.strip()))
-            write_string(f, '</description>')
+            write_string(f, "</description>")
             dec_tab()
             write_string(f, "</signal>")
         dec_tab()
         write_string(f, "</signals>")
 
     constants = c.find("constants")
-    if(constants != None and len(list(constants)) > 0):
+    if constants != None and len(list(constants)) > 0:
 
         write_string(f, "<constants>")
         inc_tab()
@@ -197,7 +218,7 @@ def write_class(c):
 
             write_string(f, '<constant name="' + escape(m.attrib["name"]) + '" value="' + m.attrib["value"] + '">')
             old_constant_descr = find_constant_descr(old_class, m.attrib["name"])
-            if (old_constant_descr):
+            if old_constant_descr:
                 write_string(f, escape(old_constant_descr.strip()))
             write_string(f, "</constant>")
 
@@ -207,9 +228,10 @@ def write_class(c):
     dec_tab()
     write_string(f, "</class>")
 
+
 for c in list(old_doc):
     old_classes[c.attrib["name"]] = c
 
 for c in list(new_doc):
     write_class(c)
-write_string(f, '</doc>\n')
+write_string(f, "</doc>\n")