DebugLoggingPlugin writes nothing for a failed run and keeps its state in memory #7890

🔴 Required Information

Describe the Bug:
DebugLoggingPlugin writes nothing for a run that fails, which is the run you most want to debug. The failed invocation's buffered entries, prompts included, also stay in memory for the life of the plugin.

The plugin buffers each invocation in _invocation_states, and writes and drops that state only in after_run_callback. The runner skips after_run_callback once a run raises (Runner._exec_with_plugin and workflow/_node_runner_utils.py) and calls on_run_error_callback instead, which this plugin doesn't implement. Every other plugin that keeps per-invocation state already handles it: BigQuery analytics, both ReflectAndRetry plugins, ModelConsultObservability and ForceEscalation.

Steps to Reproduce:

1. Register DebugLoggingPlugin(output_path="adk_debug.yaml") on an App.
2. Run an agent whose tool raises, e.g. ConnectionError("payment gateway timed out").

Expected Behavior:
adk_debug.yaml contains the failed invocation with its entries and the error, and the plugin's state for it is released.

Observed Behavior:

run failed: ConnectionError payment gateway timed out
debug file exists: False | bytes: 0
_invocation_states after the run: {'e-683b…': ['invocation_start', 'agent_start', 'llm_request', 'llm_response', 'event', 'tool_call', 'tool_error', 'event']}

Environment Details:

• ADK Library Version (pip show google-adk): 2.13.0 (also on main at e9e8f61)
• Desktop OS: macOS
• Python Version (python -V): 3.11.16

Model Information:

• Are you using LiteLLM: No
• Which model is being used: any (a fake BaseLlm in the repro)

🟡 Optional Information

Minimal Reproduction Code:

def charge_card(amount: int) -> dict:
  """Charges a card."""
  raise ConnectionError("payment gateway timed out")

plugin = DebugLoggingPlugin(output_path="adk_debug.yaml")
app = App(
    name="app",
    root_agent=LlmAgent(name="a", model=model_that_calls_charge_card, tools=[charge_card]),
    plugins=[plugin],
)
runner = InMemoryRunner(app=app)
# run_async(...) raises ConnectionError; adk_debug.yaml is never written and
# plugin._invocation_states still holds the invocation.

How often has this issue occurred?:

• Always (100%), for every run that raises