mypy environment needs a couple types pins added (#42927)

* mypy environment needs a few additional pins + the dev_requirements installed when it's running -- otherwise some types that come from optional dependencies won't resolve during type checking

Author: scbedd

eng/tools/azure-sdk-tools/azpysdk/mypy.py

@@ -17,6 +17,13 @@
 PYTHON_VERSION = "3.9"
 MYPY_VERSION = "1.14.1"
 
+ADDITIONAL_LOCKED_DEPENDENCIES = [
+  "types-chardet==5.0.4.6",
+  "types-requests==2.31.0.6",
+  "types-six==1.16.21.9",
+  "types-redis==4.6.0.7",
+  "PyGitHub>=1.59.0"
+]
 
 class mypy(Check):
     def __init__(self) -> None:
@@ -45,17 +52,23 @@ def run(self, args: argparse.Namespace) -> int:
         for parsed in targeted:
             package_dir = parsed.folder
             package_name = parsed.name
+            dev_requirements = os.path.join(package_dir, "dev_requirements.txt")
+            additional_requirements = ADDITIONAL_LOCKED_DEPENDENCIES
 
             executable, staging_directory = self.get_executable(args.isolate, args.command, sys.executable, package_dir)
             logger.info(f"Processing {package_name} for mypy check")
 
+            # # need to install dev_requirements to ensure that type-hints properly resolve
+            if os.path.exists(dev_requirements):
+                additional_requirements += ["-r", dev_requirements]
+
             # install mypy
             try:
                 if args.next:
                     # use latest version of mypy
-                    install_into_venv(executable, ["mypy"])
+                    install_into_venv(executable, ["mypy"] + additional_requirements)
                 else:
-                    install_into_venv(executable, [f"mypy=={MYPY_VERSION}"])
+                    install_into_venv(executable, [f"mypy=={MYPY_VERSION}"] + additional_requirements)
             except CalledProcessError as e:
                 logger.error("Failed to install mypy:", e)
                 return e.returncode