(torchx/specs) Support builtin list[str] and dict[str, str] runopts opt_type

Summary:
For python-3.9+ support scheduler runopt types to be specified using the built-in generic types (e.g. `list[str]` over `typing.List[str]`).

Basically lets scheduler implementations to declare their runopts (cfg) as:

```
def _run_opts(self) -> runopts:
  opts = runopts()
  opts.add("regions", type_=list[str], help="a list opt", default=[])
  opts.add("envs", type_=dict[str, str], help="a dict opt", default=[])
```

versus having to do:


```
from typing import List, Dict
def _run_opts(self) -> runopts:
  opts = runopts()
  opts.add("regions", type_=List[str], help="a list opt", default=[])
  opts.add("envs", type_=Dict[str, str], help="a dict opt", default=[])
```

Differential Revision: D78444106

Author: kiukchung

torchx/specs/api.py

@@ -951,11 +951,11 @@ def cfg_from_str(self, cfg_str: str) -> Dict[str, CfgVal]:
         def _cast_to_type(value: str, opt_type: Type[CfgVal]) -> CfgVal:
             if opt_type == bool:
                 return value.lower() == "true"
-            elif opt_type == List[str]:
+            elif opt_type in (List[str], list[str]):
                 # lists may be ; or , delimited
                 # also deal with trailing "," by removing empty strings
                 return [v for v in value.replace(";", ",").split(",") if v]
-            elif opt_type == Dict[str, str]:
+            elif opt_type in (Dict[str, str], dict[str, str]):
                 return {
                     s.split(":", 1)[0]: s.split(":", 1)[1]
                     for s in value.replace(";", ",").split(",")

torchx/specs/test/api_test.py

@@ -566,6 +566,41 @@ def test_cfg_from_str(self) -> None:
             {"E": {"f": "b", "F": "B"}}, opts.cfg_from_str("E=f:b,F:B")
         )
 
+    def test_cfg_from_str_builtin_generic_types(self) -> None:
+        # basically a repeat of "test_cfg_from_str()" but with
+        # list[str] and dict[str, str] instead of List[str] and Dict[str, str]
+        opts = runopts()
+        opts.add("K", type_=list[str], help="a list opt", default=[])
+        opts.add("J", type_=str, help="a str opt", required=True)
+        opts.add("E", type_=dict[str, str], help="a dict opt", default=[])
+
+        self.assertDictEqual({}, opts.cfg_from_str(""))
+        self.assertDictEqual({}, opts.cfg_from_str("UNKWN=b"))
+        self.assertDictEqual({"K": ["a"], "J": "b"}, opts.cfg_from_str("K=a,J=b"))
+        self.assertDictEqual({"K": ["a"]}, opts.cfg_from_str("K=a,UNKWN=b"))
+        self.assertDictEqual({"K": ["a", "b"]}, opts.cfg_from_str("K=a,b"))
+        self.assertDictEqual({"K": ["a", "b"]}, opts.cfg_from_str("K=a;b"))
+        self.assertDictEqual({"K": ["a", "b"]}, opts.cfg_from_str("K=a,b"))
+        self.assertDictEqual({"K": ["a", "b"]}, opts.cfg_from_str("K=a,b;"))
+        self.assertDictEqual(
+            {"K": ["a", "b"], "J": "d"}, opts.cfg_from_str("K=a,b,J=d")
+        )
+        self.assertDictEqual(
+            {"K": ["a", "b"], "J": "d"}, opts.cfg_from_str("K=a,b;J=d")
+        )
+        self.assertDictEqual(
+            {"K": ["a", "b"], "J": "d"}, opts.cfg_from_str("K=a;b,J=d")
+        )
+        self.assertDictEqual(
+            {"K": ["a", "b"], "J": "d"}, opts.cfg_from_str("K=a;b;J=d")
+        )
+        self.assertDictEqual(
+            {"K": ["a"], "J": "d"}, opts.cfg_from_str("J=d,K=a,UNKWN=e")
+        )
+        self.assertDictEqual(
+            {"E": {"f": "b", "F": "B"}}, opts.cfg_from_str("E=f:b,F:B")
+        )
+
     def test_resolve_from_str(self) -> None:
         opts = runopts()
         opts.add("foo", type_=str, default="", help="")