chore(ruff): bump ruff to 0.16.2 and clear surfaced lint (#26359)

## Summary & Motivation

Bumps `ruff` from `0.15.15` to `0.16.2` and clears the lint/format diff
the new version surfaces. This is a bigger bump than usual because
0.16.0 made two significant default-behavior changes: the default lint
rule set expanded from 59 to 413 rules, and the formatter now formats
Python code blocks in Markdown files.

## Pin sites and lockfiles

All six pin sites updated: root `pyproject.toml`,
`dagster-oss/python_modules/dagster/pyproject.toml` (×2: `test` and
`ruff` extras), `python_modules/purina/pyproject.toml`,
`public/skills/dagster-skills-evals/pyproject.toml`, and
`required-version` in `dagster-oss/config/ruff.toml`.

Beyond the usual two lockfiles (root `uv.lock` via `just
rebuild_uv_lock_file`, dagster's via `update_lockfiles.py`), seven more
dagster-oss lockfiles pinned the old ruff through their path dependency
on dagster's extras and were relocked with `update_lockfiles.py`:
`docs`, `examples/docs_snippets`, `examples/with_great_expectations`,
`examples/assets_pandas_type_metadata`,
`examples/docs_projects/project_components_pdf_extraction`,
`libraries/dagster-ge`, and `libraries/dagster-dg-cli`. These would
otherwise fail lockfile-staleness checks in CI.

## Lint changes

`just ruff` at 0.16.2 found 178 diagnostics; 108 auto-fixed at default
safety and 48 more with `--unsafe-fixes`. The autofix diff is dominated
by RUF036 (`None` moved to the end of unions, newly stabilized) plus
assorted comprehension cleanups, stale-`noqa` removals, and typing
modernization. One explanatory comment dropped by the union-reordering
fix in `dagster_shared/serdes/serdes.py` was restored by hand.

Hand fixes for the non-autofixable residue:

- **UP035** in `_core/types/{config_schema,dagster_type,decorator}.py`:
replaced deprecated `typing.AbstractSet` with `collections.abc.Set as
AbstractSet` (existing repo convention) and `typing.Type` with builtin
`type`.
- **B020/PLR1704** in `_core/types/python_dict.py`: renamed a loop
variable that shadowed the `value` argument it iterates.
- **DTZ005** in `project_multi_tenant` schedules and the
`databricks-delta` lakehouse component: `datetime.now()` →
`datetime.now(timezone.utc)` (demo-data timestamps and schedule-tag
fallbacks are now tz-aware).

Config-level ignores where the newly-defaulted rules are wrong for the
context:

- `project_dspy`: `BLE001` (example code deliberately catches broad
exceptions when scoring LLM output) and `RUF012` (same class-attribute
false-positive class the shared config ignores globally). These files
are embedded in docs via snippet markers, so `noqa` comments would leak
into rendered docs.
- `dagster-skills-evals`: `PLR0917` (too-many-positional-arguments,
newly stabilized) alongside the existing `PLR0913` ignore — typer CLI
commands legitimately take many parameters.
- `project_multi_tenant`: `UP017` — the project targets py311 so ruff
wants `datetime.UTC`, but the ty master env type-checks examples at
Python 3.10 (dagster's minimum) where that symbol doesn't exist.

## Markdown formatting

102 `.md` files had their Python code fences reformatted (~1,700 lines)
by the new default Markdown formatting. Kept rather than excluded via
`format.exclude`: CI's `ruff format --check` enforces it, and the repo
precedent (0.15.0 bump) was to adopt new formatter defaults wholesale.
Spot-checked the largest diffs (`MIGRATION.md`, `CHANGES.md`, docs
guides) — all benign style normalization inside valid-Python fences.

## Test Plan

- [x] `just ruff` clean (`All checks passed!`, formatter no-op on second
run).
- [x] `just ty` clean (`Found 0 errors / Found 0 warnings`, 7257 files)
across all three ty environments — confirms the unsafe-fix import
deletions and the `typing.AbstractSet`/`typing.Type` replacements don't
break annotation resolution.
- [x] `rg` confirms no lockfile anywhere still references
`ruff==0.15.15`.

Internal-RevId: 56253058f2358df14a7a0ea4345dbf4eca23f75c

Author: smackesey

.claude/coding_conventions.md

@@ -39,6 +39,7 @@ from contextlib import contextmanager
 from dagster._core.definitions import JobDefinition
 from dagster._utils.error import DagsterError
 
+
 @contextmanager
 def my_function():
     job = JobDefinition(...)
@@ -51,6 +52,7 @@ def my_function():
 def my_function():
     from dagster._core.definitions import JobDefinition
     from dagster._utils.error import DagsterError
+
     job = JobDefinition(...)
 ```
 
@@ -68,6 +70,7 @@ if TYPE_CHECKING:
 def create_job():
     # Import here to avoid circular dependency
     from dagster._core.definitions import JobDefinition
+
     return JobDefinition(...)
 ```
 
@@ -154,13 +157,16 @@ def my_command():
 ```python
 _service: Optional[MyService] = None
 
+
 def get_service() -> Optional[MyService]:
     return _service
 
+
 def initialize_service():
     global _service
     _service = MyService()
 
+
 def some_function():
     service = get_service()  # Hidden dependency
 ```
@@ -171,6 +177,7 @@ def some_function():
 def create_service() -> MyService:
     return MyService()
 
+
 def some_function(service: MyService):  # Explicit dependency
     service.do_something()
 ```
@@ -187,6 +194,7 @@ from typing import Literal
 
 DiagnosticsLevel = Literal["off", "error", "info", "debug"]
 
+
 def create_service(level: DiagnosticsLevel = "off") -> MyService:
     return MyService(level=level)
 ```
@@ -330,13 +338,18 @@ def _get_asset_value_with_fallback(context, asset_key, default_value):
     so we use exception handling to detect this case.
     """
     try:
-        return context.instance.get_latest_materialization_event(asset_key).asset_materialization.metadata
+        return context.instance.get_latest_materialization_event(
+            asset_key
+        ).asset_materialization.metadata
     except Exception:
         return default_value
 
+
 # BAD: Exception control flow exposed in main logic
 try:
-    metadata = context.instance.get_latest_materialization_event(asset_key).asset_materialization.metadata
+    metadata = context.instance.get_latest_materialization_event(
+        asset_key
+    ).asset_materialization.metadata
 except Exception:
     metadata = default_value
 ```
@@ -457,11 +470,13 @@ return parse_asset_key_from_string(key_str)
 # ✅ GOOD: Using click.echo for CLI output
 import click
 
+
 @click.command()
 def my_command():
     click.echo("Processing started...")
     click.echo(f"Found {count} items")
 
+
 # ❌ BAD: Using print in CLI code
 @click.command()
 def my_command():

CHANGES.md

@@ -1247,7 +1247,7 @@ This version of Dagster inadvertently did not include the webapp code in the pub
   ```python
   @dg.asset(deps=[the_asset])
   def the_downstream_asset(context: dg.AssetExecutionContext):
-    return context.load_asset_value(dg.AssetKey("the_asset"))
+      return context.load_asset_value(dg.AssetKey("the_asset"))
   ```
 - Expose asset_selection parameter for `submit_job_execution` function in DagsterGraphQLClient, thanks [@brunobbaraujo](https://github.com/brunobbaraujo)!
 - Large error stack traces from Dagster events will be automatically truncated if the message or stack trace exceeds 500kb. The exact value of the truncation can be overridden by setting the `DAGSTER_EVENT_ERROR_FIELD_SIZE_LIMIT` environment variable.
@@ -3148,10 +3148,12 @@ This version of Dagster resulted in errors when trying to launch runs that targe
   ```python
   from dagster import asset, Definitions
 
+
   @asset
   def my_asset(): ...
 
-  defs = Definitions(assets=[my_asset, my_asset]) # Deduped into just one AssetsDefinition.
+
+  defs = Definitions(assets=[my_asset, my_asset])  # Deduped into just one AssetsDefinition.
   ```
 
 - [dagster-embedded-elt] Adds translator options for dlt integration to override auto materialize policy, group name, owners, and tags
@@ -4855,8 +4857,8 @@ meta:
 - `AssetExecutionContext` is now a subclass of `OpExecutionContext`, not a type alias. The code
 
 ```python
-def my_helper_function(context: AssetExecutionContext):
-    ...
+def my_helper_function(context: AssetExecutionContext): ...
+
 
 @op
 def my_op(context: OpExecutionContext):
@@ -4870,13 +4872,12 @@ will cause type checking errors. To migrate, update type hints to respect the ne
 ```python
 ## old
 @op
-def my_op(context: AssetExecutionContext):
-    ...
+def my_op(context: AssetExecutionContext): ...
+
 
 ## correct
 @op
-def my_op(context: OpExecutionContext):
-    ...
+def my_op(context: OpExecutionContext): ...
 ```
 
 - [ui] We have removed the option to launch an asset backfill as a single run. To achieve this behavior, add `backfill_policy=BackfillPolicy.single_run()` to your assets.
@@ -5078,8 +5079,7 @@ def my_op(context: OpExecutionContext):
 
   ```python
   @asset_check(asset=my_asset)
-  def my_check(my_asset) -> AssetCheckResult:
-      ...
+  def my_check(my_asset) -> AssetCheckResult: ...
   ```
 
 - [Breaking] `AssetCheckSpec` now takes `asset=` instead of `asset_key=`, and can accept either a key or an asset definition.
@@ -5453,9 +5453,7 @@ def my_op(context: OpExecutionContext):
 
 ```python
 dbt_manifest.build_schedule(
-  job_name="materialize_dbt_models",
-  cron_schedule="0 0 * * *",
-  dbt_select="fqn:*"
+    job_name="materialize_dbt_models", cron_schedule="0 0 * * *", dbt_select="fqn:*"
 )
 ```
 
@@ -5663,13 +5661,16 @@ models:
   class GreetingConfig(Config):
       message: str
 
+
   @op
   def greeting_op(config: GreetingConfig):
       print(config.message)
 
+
   class HelloConfig(Config):
       name: str
 
+
   @configured(greeting_op)
   def hello_op(config: HelloConfig):
       return GreetingConfig(message=f"Hello, {config.name}!")
@@ -6230,10 +6231,12 @@ models:
   class MyResource(ConfigurableResource):
       pass
 
+
   @op
   def my_op(x: int, y: int, my_resource: MyResource) -> int:
       return x + y
 
+
   my_op(4, 5, my_resource=MyResource())
   ```
 
@@ -6608,13 +6611,14 @@ Stay tuned, as this is only the first part of the overhaul. We’ll be adding mo
 ```python
 from dagster import asset, job, op
 
+
 @asset
-def emails_to_send():
-    ...
+def emails_to_send(): ...
+
 
 @op
-def send_emails(emails) -> None:
-    ...
+def send_emails(emails) -> None: ...
+
 
 @job
 def send_emails_job():