Unify task/asset state storage between Core API and Execution API

[amoghrajesh]

---

Was generative AI tooling used to co-author this PR?

• Yes: claude sonnet 4.6

What problem are we solving?

Task and asset state written by workers (via the Execution API) is stored as JSON-encoded strings in the DB — e.g., the integer 42 is stored as "42", and the string "hello" as '"hello"'. The core API read path returned the raw DB string without decoding it, so callers saw '"hello"' instead of "hello" and "42" (a string) instead of 42 (an integer).

The write path had the inverse bug: values posted to the core API were stored without json.dumps, so a worker reading them back via the execution API would hit a JSONDecodeError.

Current behaviour

• GET /dags/{dag_id}/dagRuns/{run_id}/taskInstances/{task_id}/states and the equivalent asset state endpoints return raw JSON-encoded strings in the value field (e.g. ""hello"", "42" as a string).
• PUT on these endpoints stores the value as-is without JSON-encoding, so values written via the Core API are unreadable by workers.
• The value field on request/response models is typed as str, with no null or size validation.

Classic example is if I run this task:

@taskdefmy_task(**context: Context):
task_state=context["task_state"]
task_state.set("job_id", "12345")
task_state.set("secret-dict", {"key": "value"})
task_state.set("int_value", 42)
print("Fetching task states I stored earlier")
print("job_id:", task_state.get("job_id"))
print("secret-dict:", task_state.get("secret-dict"))
print("int_value:", task_state.get("int_value"))
my_task()

Core API call to get all task states returned this:

{
"task_states": [
{
"key": "int_value",
"value": "42",
"updated_at": "2026-05-26T10:07:01.872139Z",
"expires_at": "2026-06-25T10:07:01.868443Z"
},
{
"key": "job_id",
"value": "\"12345\"",
"updated_at": "2026-05-26T10:07:01.855922Z",
"expires_at": "2026-06-25T10:07:01.851283Z"
},
{
"key": "secret-dict",
"value": "{\"key\": \"value\"}",
"updated_at": "2026-05-26T10:07:01.864312Z",
"expires_at": "2026-06-25T10:07:01.860810Z"
}
],
"total_entries": 3
}

Proposed change

• value: str widened to value: JsonValue on all four core API datamodels (TaskStateBody, TaskStateResponse, AssetStateBody, AssetStateResponse).
• Write paths now call json.dumps(body.value) before passing to the backend, matching the execution API as introduced in Simplifing authoring of task and asset states by allowing JSON types #67418
• Read paths now call json.loads(r.value) when constructing responses, so callers receive native types (int, dict, list, bool, str).
• Body models now have validators rejecting null, non-finite floats (NaN, Inf, -Inf), and values whose serialized form exceeds 65535 bytes (preserving the old max_length constraint).

NOTE: The UI PR: #67292 sends in raw values as entered by user, so no impact there.

Testing

Test 1: Set using task execution, Get using core API and task execution should have same response type

Test 2: Value set using core API, getting via task execution and core API should have same response type

Set values using curl for this task:

@taskdefmy_task(**context: Context):
task_state=context["task_state"]
print("Fetching task states that are set by API")
print("str_value:", task_state.get("str_value"), type(task_state.get("str_value")))
print("dict-value:", task_state.get("dict-value"), type(task_state.get("dict-value")))
print("int_value:", task_state.get("int_value"), type(task_state.get("int_value")))
my_task()

---

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[amoghrajesh]

Thanks for reviews, merging this one

[github-actions]

Backport failed to create: airflow-ctl/v0-1-test. View the failure log Run details

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
❌	airflow-ctl/v0-1-test

You can attempt to backport this manually by running:

cherry_picker c1299bd airflow-ctl/v0-1-test

This should apply the commit to the airflow-ctl/v0-1-test branch and leave the commit in conflict state marking
the files that need manual conflict resolution.

After you have resolved the conflicts, you can continue the backport process by running:

cherry_picker --continue

If you don't have cherry-picker installed, see the installation guide.

[amoghrajesh]

No need to backport this