Use sys.version_info to guard imports (#1177)

**Pull Request Checklist**
- [ ] Fixes #<!--issue number goes here-->
- [ ] Tests added
- [ ] Documentation/examples added
- [X] [Good commit messages](https://cbea.ms/git-commit/) and/or PR
title

**Description of PR**
Currently, conditional imports that depend on Python version are using
`try/except ImportError` to import from `typing_extensions` on older
Python versions. This is not natively supported by typecheckers, forcing
use of error suppression, and losing potential validation of downstream
code. (Additionally, pyright is erroneously flagging a lot of code that
uses `Annotated` with "Call expression not allowed in type expression,
making it harder to spot real issues in VSCode.)

This PR refactors these conditional imports to use the recommended `if
sys.version_info >= (3, minor):` pattern instead.

See also: [mypy issue
comment](python/mypy#1393 (comment)),
[pyright issue
comment](microsoft/pyright#4160 (comment))

Signed-off-by: Alice Purcell <alicederyn@gmail.com>

docs/examples/workflows/experimental/script_annotations_artifact_custom_volume.md

@@ -8,14 +8,12 @@ This example will reuse the outputs volume across script steps.
 === "Hera"
 
     ```python linenums="1"
-    from hera.workflows.artifact import ArtifactLoader
-    from hera.workflows.volume import Volume
-
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
+    import sys
 
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
     from hera.shared import global_config
     from hera.workflows import (
@@ -28,6 +26,8 @@ This example will reuse the outputs volume across script steps.
         models as m,
         script,
     )
+    from hera.workflows.artifact import ArtifactLoader
+    from hera.workflows.volume import Volume
 
     global_config.experimental_features["script_annotations"] = True
 

docs/examples/workflows/experimental/script_annotations_artifact_loaders.md

@@ -9,13 +9,14 @@
 
     ```python linenums="1"
     import json
+    import sys
     from pathlib import Path
     from typing import Dict
 
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
     from hera.shared import global_config
     from hera.workflows import Artifact, ArtifactLoader, Parameter, Steps, Workflow, script

docs/examples/workflows/experimental/script_annotations_artifact_outputs_defaults.md

@@ -8,14 +8,12 @@ This example will reuse the outputs volume across script steps.
 === "Hera"
 
     ```python linenums="1"
-    from hera.workflows.artifact import ArtifactLoader
-    from hera.workflows.volume import Volume
-
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
+    import sys
 
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
     from hera.shared import global_config
     from hera.workflows import (
@@ -25,6 +23,8 @@ This example will reuse the outputs volume across script steps.
         Workflow,
         script,
     )
+    from hera.workflows.artifact import ArtifactLoader
+    from hera.workflows.volume import Volume
 
     global_config.experimental_features["script_annotations"] = True
 

docs/examples/workflows/experimental/script_annotations_artifact_passing.md

@@ -8,14 +8,14 @@ This example will reuse the outputs volume across script steps.
 === "Hera"
 
     ```python linenums="1"
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
-
-
+    import sys
     from pathlib import Path
 
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
+
     from hera.shared import global_config
     from hera.workflows import (
         Artifact,

docs/examples/workflows/experimental/script_annotations_inputs.md

@@ -8,12 +8,13 @@
 === "Hera"
 
     ```python linenums="1"
+    import sys
     from typing import Dict
 
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
     from hera.shared import global_config
     from hera.workflows import Artifact, ArtifactLoader, Parameter, Steps, Workflow, script

docs/examples/workflows/experimental/script_annotations_outputs.md

@@ -8,14 +8,15 @@
 === "Hera"
 
     ```python linenums="1"
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
-
+    import sys
     from pathlib import Path
     from typing import Tuple
 
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
+
     from hera.shared import global_config
     from hera.workflows import Artifact, Parameter, RunnerScriptConstructor, Steps, Workflow, script
 

docs/examples/workflows/experimental/script_runner_io.md

@@ -8,6 +8,13 @@
 === "Hera"
 
     ```python linenums="1"
+    import sys
+
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
+
     try:
         from pydantic.v1 import BaseModel
     except ImportError:
@@ -18,11 +25,6 @@
     from hera.workflows.archive import NoneArchiveStrategy
     from hera.workflows.io import Input, Output
 
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
-
     global_config.experimental_features["script_pydantic_io"] = True
 
 

docs/examples/workflows/scripts/callable_script.md

@@ -8,18 +8,18 @@
 === "Hera"
 
     ```python linenums="1"
+    import sys
     from typing import List, Union
 
-    from hera.shared.serialization import serialize
-
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
     from pydantic import BaseModel
 
     from hera.shared import global_config
+    from hera.shared.serialization import serialize
     from hera.workflows import Parameter, Script, Steps, Workflow, script
 
     # Note, setting constructor to runner is only possible if the source code is available

docs/examples/workflows/scripts/callable_script_v1.md

@@ -8,21 +8,21 @@
 === "Hera"
 
     ```python linenums="1"
+    import sys
     from typing import List, Union
 
-    from hera.shared.serialization import serialize
+    if sys.version_info >= (3, 9):
+        from typing import Annotated
+    else:
+        from typing_extensions import Annotated
 
-    try:
-        from typing import Annotated  # type: ignore
-    except ImportError:
-        from typing_extensions import Annotated  # type: ignore
     try:
         from pydantic.v1 import BaseModel
     except (ImportError, ModuleNotFoundError):
         from pydantic import BaseModel
 
-
     from hera.shared import global_config
+    from hera.shared.serialization import serialize
     from hera.workflows import Parameter, RunnerScriptConstructor, Script, Steps, Workflow, script
 
     # Note, setting constructor to runner is only possible if the source code is available

examples/workflows/experimental/script_annotations_artifact_custom_volume.py

@@ -1,13 +1,11 @@
 """This example will reuse the outputs volume across script steps."""
 
-from hera.workflows.artifact import ArtifactLoader
-from hera.workflows.volume import Volume
-
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
+import sys
 
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from hera.shared import global_config
 from hera.workflows import (
@@ -20,6 +18,8 @@
     models as m,
     script,
 )
+from hera.workflows.artifact import ArtifactLoader
+from hera.workflows.volume import Volume
 
 global_config.experimental_features["script_annotations"] = True
 

examples/workflows/experimental/script_annotations_artifact_loaders.py

@@ -1,11 +1,12 @@
 import json
+import sys
 from pathlib import Path
 from typing import Dict
 
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from hera.shared import global_config
 from hera.workflows import Artifact, ArtifactLoader, Parameter, Steps, Workflow, script

examples/workflows/experimental/script_annotations_artifact_outputs_defaults.py

@@ -1,13 +1,11 @@
 """This example will reuse the outputs volume across script steps."""
 
-from hera.workflows.artifact import ArtifactLoader
-from hera.workflows.volume import Volume
-
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
+import sys
 
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from hera.shared import global_config
 from hera.workflows import (
@@ -17,6 +15,8 @@
     Workflow,
     script,
 )
+from hera.workflows.artifact import ArtifactLoader
+from hera.workflows.volume import Volume
 
 global_config.experimental_features["script_annotations"] = True
 

examples/workflows/experimental/script_annotations_artifact_passing.py

@@ -1,13 +1,13 @@
 """This example will reuse the outputs volume across script steps."""
 
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
-
-
+import sys
 from pathlib import Path
 
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
+
 from hera.shared import global_config
 from hera.workflows import (
     Artifact,

examples/workflows/experimental/script_annotations_inputs.py

@@ -1,9 +1,10 @@
+import sys
 from typing import Dict
 
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from hera.shared import global_config
 from hera.workflows import Artifact, ArtifactLoader, Parameter, Steps, Workflow, script

examples/workflows/experimental/script_annotations_outputs.py

@@ -1,11 +1,12 @@
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
-
+import sys
 from pathlib import Path
 from typing import Tuple
 
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
+
 from hera.shared import global_config
 from hera.workflows import Artifact, Parameter, RunnerScriptConstructor, Steps, Workflow, script
 

examples/workflows/experimental/script_runner_io.py

@@ -1,3 +1,10 @@
+import sys
+
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
+
 try:
     from pydantic.v1 import BaseModel
 except ImportError:
@@ -8,11 +15,6 @@
 from hera.workflows.archive import NoneArchiveStrategy
 from hera.workflows.io import Input, Output
 
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
-
 global_config.experimental_features["script_pydantic_io"] = True
 
 

examples/workflows/scripts/callable_script.py

@@ -1,15 +1,15 @@
+import sys
 from typing import List, Union
 
-from hera.shared.serialization import serialize
-
-try:
-    from typing import Annotated  # type: ignore
-except ImportError:
-    from typing_extensions import Annotated  # type: ignore
+if sys.version_info >= (3, 9):
+    from typing import Annotated
+else:
+    from typing_extensions import Annotated
 
 from pydantic import BaseModel
 
 from hera.shared import global_config
+from hera.shared.serialization import serialize
 from hera.workflows import Parameter, Script, Steps, Workflow, script
 
 # Note, setting constructor to runner is only possible if the source code is available