chore(fill): fix --fork/from/until for transition forks

docs/CHANGELOG.md

@@ -15,10 +15,11 @@ Test fixtures for use by clients are available for each release on the [Github r
 - ✨ Add support for Nethermind's `nethtest` command to `consume direct` ([#1250](https://github.com/ethereum/execution-spec-tests/pull/1250)).
 - ✨ Allow filtering of test cases by fork via pytest marks (via, e.g., `-m "Cancun or Prague"`) ([#1304](https://github.com/ethereum/execution-spec-tests/pull/1304)).
 - 🐞 Improve index generation of ethereum/tests fixtures: Allow generation at any directory level and include `generatedTestHash` in the index file for the `fixture_hash` ([#1303](https://github.com/ethereum/execution-spec-tests/pull/1303)).
+- 🐞 Fix `--fork/from/until` for transition forks when using `fill` [#1311](https://github.com/ethereum/execution-spec-tests/pull/1311).
 
 ### 📋 Misc
 
-- Bump the version of `execution-specs` used by the framework to the package [`ethereum-execution==1.17.0rc6.dev1`](https://pypi.org/project/ethereum-execution/1.17.0rc6.dev1/); bump the version used for test fixture generation for forks < Prague to current `execution-specs` master, [fa847a0](https://github.com/ethereum/execution-specs/commit/fa847a0e48309debee8edc510ceddb2fd5db2f2e) ([#1310](https://github.com/ethereum/execution-spec-tests/pull/1310)).
+- 🔀 Bump the version of `execution-specs` used by the framework to the package [`ethereum-execution==1.17.0rc6.dev1`](https://pypi.org/project/ethereum-execution/1.17.0rc6.dev1/); bump the version used for test fixture generation for forks < Prague to current `execution-specs` master, [fa847a0](https://github.com/ethereum/execution-specs/commit/fa847a0e48309debee8edc510ceddb2fd5db2f2e) ([#1310](https://github.com/ethereum/execution-spec-tests/pull/1310)).
 
 ### 🧪 Test Cases
 

src/pytest_plugins/forks/forks.py

@@ -443,15 +443,14 @@ def get_fork_option(config, option_name: str, parameter_name: str) -> Set[Fork]:
         config_str = config.getoption(option_name)
         if not config_str:
             return set()
+
         forks_str = config_str.split(",")
-        for i in range(len(forks_str)):
-            forks_str[i] = forks_str[i].strip().capitalize()
-            if forks_str[i] == "Merge":
-                forks_str[i] = "Paris"
+        forks_str = [s.strip() for s in config_str.split(",")]
+        # Alias for "Merge"
+        forks_str = [("Paris" if s.lower() == "merge" else s) for s in forks_str]
 
         resulting_forks = set()
-
-        for fork in get_forks():
+        for fork in config.all_forks_with_transitions:
             if fork.name() in forks_str:
                 resulting_forks.add(fork)
 
@@ -490,18 +489,16 @@ def get_fork_option(config, option_name: str, parameter_name: str) -> Set[Fork]:
         pytest.exit("Invalid command-line options.", returncode=pytest.ExitCode.USAGE_ERROR)
 
     if single_fork:
-        forks_from = single_fork
-        forks_until = single_fork
+        selected_fork_set = single_fork
     else:
         if not forks_from:
             forks_from = get_forks_with_no_parents(forks)
         if not forks_until:
             forks_until = get_last_descendants(set(get_deployed_forks()), forks_from)
-
-    selected_fork_set = get_from_until_fork_set(forks, forks_from, forks_until)
-    for fork in list(selected_fork_set):
-        transition_fork_set = transition_fork_to(fork)
-        selected_fork_set |= transition_fork_set
+        selected_fork_set = get_from_until_fork_set(forks, forks_from, forks_until)
+        for fork in list(selected_fork_set):
+            transition_fork_set = transition_fork_to(fork)
+            selected_fork_set |= transition_fork_set
 
     config.selected_fork_set = selected_fork_set  # type: ignore
 

src/pytest_plugins/forks/tests/test_markers.py

@@ -112,6 +112,14 @@ def test_case(state_test):
             {"passed": 2, "failed": 0, "skipped": 0, "errors": 0},
             id="valid_at_transition_to,subsequent_forks=True,until",
         ),
+        pytest.param(
+            generate_test(
+                valid_at_transition_to='"Cancun"',
+            ),
+            ["--fork=ShanghaiToCancunAtTime15k"],
+            {"passed": 1, "failed": 0, "skipped": 0, "errors": 0},
+            id="valid_at_transition_to,--fork=transition_fork_only",
+        ),
     ],
 )
 def test_fork_markers(pytester, test_function: str, outcomes: dict, pytest_args: List[str]):