use string replacements to generate Qt5 forms

They are mostly compatible, and this means a Qt5 install is not required
as part of the build process.

qt/aqt/forms/BUILD.bazel

@@ -2,31 +2,16 @@ load("@rules_python//python:defs.bzl", "py_binary")
 load("compile.bzl", "compile_all")
 
 py_binary(
-    name = "build_ui_qt5",
-    srcs = ["build_ui_qt5.py"],
-    legacy_create_init = False,
-    deps = ["@pyqt5//:pkg"],
-)
-
-py_binary(
-    name = "build_ui_qt6",
-    srcs = ["build_ui_qt6.py"],
+    name = "build_ui",
+    srcs = ["build_ui.py"],
     legacy_create_init = False,
     deps = ["@pyqt6//:pkg"],
 )
 
 compile_all(
-    name = "forms_qt5",
+    name = "generated_forms",
     srcs = glob(["*.ui"]),
-    builder = "build_ui_qt5",
-    suffix = "_qt5",
-)
-
-compile_all(
-    name = "forms_qt6",
-    srcs = glob(["*.ui"]),
-    builder = "build_ui_qt6",
-    suffix = "_qt6",
+    builder = "build_ui",
 )
 
 filegroup(
@@ -39,8 +24,7 @@ filegroup(
             "build_ui*.py",
         ],
     ) + [
-        ":forms_qt6",
-        ":forms_qt5",
+        ":generated_forms",
     ],
     visibility = [
         "//qt/aqt:__pkg__",

qt/aqt/forms/build_ui.py

@@ -0,0 +1,55 @@
+import re
+import sys
+import io
+from PyQt6.uic import compileUi
+
+def compile(ui_file: str) -> str:
+    buf = io.StringIO()
+    compileUi(open(ui_file), buf)
+    return buf.getvalue()
+
+def with_fixes_for_qt6(code: str) -> str:
+    code = code.replace(
+        "from PyQt6 import QtCore, QtGui, QtWidgets",
+        "from PyQt6 import QtCore, QtGui, QtWidgets\nfrom aqt.utils import tr\n"
+    )
+    code = re.sub(
+        r'(?:QtGui\.QApplication\.)?_?translate\(".*?", "(.*?)"', "tr.\\1(", code
+    )
+    outlines = []
+    qt_bad_types = [
+        ".connect(",
+    ]
+    for line in code.splitlines():
+        for substr in qt_bad_types:
+            if substr in line:
+                line = line + "  # type: ignore"
+                break
+        if line == "from . import icons_rc":
+            continue
+        line = line.replace(":/icons/", "icons:")
+        line = line.replace("QAction.PreferencesRole", "QAction.MenuRole.PreferencesRole")
+        line = line.replace("QAction.AboutRole", "QAction.MenuRole.AboutRole")
+        line = line.replace("QComboBox.AdjustToMinimumContentsLength", "QComboBox.SizeAdjustPolicy.AdjustToMinimumContentsLength")
+        outlines.append(line)
+    return "\n".join(outlines)
+
+def with_fixes_for_qt5(code: str) -> str:
+    code = code.replace("Qt6", "Qt5")
+    code = code.replace("QtGui.QAction", "QtWidgets.QAction")
+    return code
+
+if __name__ == "__main__":
+    ui_file = sys.argv[1]
+    py5_file = sys.argv[2]
+    py6_file = sys.argv[3]
+
+    stock = compile(ui_file)
+    for_qt6 = with_fixes_for_qt6(stock)
+    for_qt5 = with_fixes_for_qt5(for_qt6)
+
+    with open(py5_file, "w") as file:
+        file.write(for_qt5)
+
+    with open(py6_file, "w") as file:
+        file.write(for_qt6)

qt/aqt/forms/compile.bzl

@@ -1,12 +1,13 @@
-def compile(name, ui_file, py_file, builder):
+def compile(name, ui_file, qt5_file, qt6_file, builder):
     native.genrule(
         name = name,
         srcs = [ui_file],
-        outs = [py_file],
-        cmd = "$(location {builder}) $(location {ui_file}) $(location {py_file})".format(
+        outs = [qt5_file, qt6_file],
+        cmd = "$(location {builder}) $(location {ui_file}) $(location {qt5_file}) $(location {qt6_file})".format(
             builder = builder,
             ui_file = ui_file,
-            py_file = py_file,
+            qt5_file = qt5_file,
+            qt6_file = qt6_file,
         ),
         tools = [
             builder,
@@ -14,13 +15,14 @@ def compile(name, ui_file, py_file, builder):
         message = "Building UI",
     )
 
-def compile_all(name, builder, srcs, suffix):
+def compile_all(name, builder, srcs):
     py_files = []
     for ui_file in srcs:
-        fname = ui_file.replace(".ui", "") + suffix
-        py_file = fname + ".py"
-        py_files.append(py_file)
-        compile(fname, ui_file, py_file, builder)
+        base = ui_file.replace(".ui", "")
+        qt5_file = base + "_qt5.py"
+        qt6_file = base + "_qt6.py"
+        py_files.extend([qt5_file, qt6_file])
+        compile(base, ui_file, qt5_file, qt6_file, builder)
 
     native.filegroup(
         name = name,