SqliteSpanExporter drops a span's status and events, so an exception that ended a run is lost (2.11.0) #7484

🔴 Required Information

Describe the Bug:
SqliteSpanExporter (telemetry/sqlite_span_exporter.py), the exporter that "exports spans to a local SQLite database" for local development, does not store a span's status or its events. OpenTelemetry keeps an exception in both: start_as_current_span sets the status to ERROR with the exception's description, and records an exception event with its type, message and stack trace. ADK does the same in trace_tool_call and node_tracing. The spans table has no column for either, and _row_to_readable_span rebuilds each span without them. So a run that fails leaves spans that read back as if nothing went wrong: status UNSET, no events. The error that stopped the run, the main thing a local trace is kept for, is lost.

Steps to Reproduce:

1. pip install "google-adk==2.11.0" (opentelemetry-sdk 1.42.1)
2. Run the script below. It needs no key or network.
3. It ends a span with an exception, exports it with SqliteSpanExporter, and reads it back with get_all_spans_for_session.

Expected Behavior:
The span reads back with status ERROR, its description, and the exception event (type, message, stack trace).

Observed Behavior:

columns: ['span_id', 'trace_id', 'parent_span_id', 'name', 'start_time_unix_nano', 'end_time_unix_nano', 'session_id', 'invocation_id', 'attributes_json']
status read back: UNSET
events read back: []

The table on main is the same.

Environment Details:

• ADK Library Version (pip show google-adk): 2.11.0
• Desktop OS: Linux
• Python Version (python -V): 3.11.13

Model Information:

• Are you using LiteLLM: No
• Which model is being used: not relevant (any span)

🟡 Optional Information

Regression: Not known.

Minimal Reproduction Code:

"""SqliteSpanExporter drops a span's status and events (exceptions)."""

import sqlite3
import tempfile
from pathlib import Path

from google.adk.telemetry.sqlite_span_exporter import SqliteSpanExporter
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import SimpleSpanProcessor

db = str(Path(tempfile.mkdtemp()) / "spans.db")
exporter = SqliteSpanExporter(db_path=db)
provider = TracerProvider()
provider.add_span_processor(SimpleSpanProcessor(exporter))
tracer = provider.get_tracer("repro")

try:
    with tracer.start_as_current_span(
        "call_llm", attributes={"gcp.vertex.agent.session_id": "s1"}
    ):
        raise ValueError("model: claude-sonnet-9-9 not found")
except ValueError:
    pass

columns = [r[1] for r in sqlite3.connect(db).execute("PRAGMA table_info(spans)")]
print("columns:", columns)
(span,) = exporter.get_all_spans_for_session("s1")
print("status read back:", span.status.status_code.name)
print("events read back:", list(span.events))

Possible fix: add status_code, status_description and events_json columns (with ALTER TABLE ... ADD COLUMN for an existing file), write them in export, and restore them in _row_to_readable_span.

How often has this issue occurred?: Always (100%).