Merge branch 'main' of git.stroblme.de:Fluksio/app

The two sides both touched `submit_ready`'s readiness check, for unrelated
reasons, so the conflict is textual rather than semantic and both changes
stand:

- `831a537` completes a node that is not ready instead of passing over it,
  so a producer that can never run stops stranding its consumers.
- the audit branch has `_is_node_ready` return the values it read, so the
  node runs on them instead of asking state for the same keys again.

Merged as: read once, keep the values whether or not the answer is yes, and
take the not-ready branch from `831a537`. Its reasoning holds under the
merge — by the time readiness is consulted, `in_degree` is zero and every
in-wave producer has finished, so the answer cannot change later in the
wave.

Also fixes a fixture this branch added: the module-scoped row cleanup in
`tests/conftest.py` assumed a schema, and `tests/flow` overrides `db` with a
no-op because those tests need no database. It only showed when that
directory ran on its own.

746 tests green, and each directory green alone. Engine throughput is
unchanged by the merge (559 msg/s on the memory backend, against 639 before
it and 262 at the start of the audit).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6hPWS6YEbT1P8LxhhFb2T

backend/fluksio/flow/pipeline.py

@@ -1352,12 +1352,30 @@ class Pipeline:
                         continue
                     ready_inputs: dict[str, Any] | None = None
                     if check_ready:
+                        # The values are kept whether or not the answer is yes:
+                        # a node that may run reads them below instead of
+                        # asking state for the same keys again.
                         ready, ready_inputs = self._is_node_ready(n, state)
                         if not ready:
-                            if n.synchronous:
-                                # Not ready now; a later trigger may make it
-                                # ready.
-                                skipped.add(n)
+                            # Completed, not merely passed over: a later trigger
+                            # may still make it ready, but not running is not
+                            # the same as blocking. Whatever it last published
+                            # is in state, and a consumer reading that alongside
+                            # something this wave *did* publish has every right
+                            # to run on the pair.
+                            #
+                            # Passing over it held that consumer for the whole
+                            # wave, and a node that can never be ready — an
+                            # input nothing has ever published — took its
+                            # consumers out for good. On this house
+                            # `plugs.pump_run` waits on a watering pulse that
+                            # only exists at 02:00, and it sits upstream of
+                            # `dmx.switches`: every boiler, plug and appliance
+                            # command reached its own message and stopped there,
+                            # reaching the DMX universe only in the occasional
+                            # wave the pump node happened not to be part of.
+                            complete(n)
+                            progressed = True
                             continue
                     if replay and entry_id and self._already_done(entry_id, n):
                         # Its side effect happened on an earlier delivery; its
@@ -1379,17 +1397,23 @@ class Pipeline:
 
                 for n in completed:
                     result = node_futures.pop(n).result()
-                    # A node returning nothing (rate limiting, an error) stops
-                    # propagation along its branch.
-                    if result is not None:
-                        # Before the decrement: a consumer freed by this node
-                        # is judged on what it just published.
-                        if fresh is not None:
-                            fresh.update(result)
-                        for consumer in edges[n]:
-                            if consumer in target_nodes:
-                                in_degree[consumer] -= 1
-                        submit_ready(executor)
+                    # Before the decrement: a consumer freed by this node is
+                    # judged on what it just published.
+                    if result is not None and fresh is not None:
+                        fresh.update(result)
+                    # Decremented whatever it returned. A node that published
+                    # nothing — rate limited, unchanged, or failed — has not
+                    # *blocked* its consumers; it has merely given them nothing
+                    # to read, and `untouched` above is the accurate test of
+                    # that. Holding the count instead made a quiet producer
+                    # veto a noisy sibling: `dmx.switches` reads both boilers
+                    # through report-by-exception nodes, so the kitchen one
+                    # staying silent — which is almost always — kept the main
+                    # boiler's command from ever reaching the DMX universe.
+                    for consumer in edges[n]:
+                        if consumer in target_nodes:
+                            in_degree[consumer] -= 1
+                    submit_ready(executor)
 
         if self._node_pool is not None:
             # The execution service owns a long-lived pool; building one per

backend/tests/conftest.py

@@ -7,7 +7,7 @@ from typing import Any
 import pytest
 from cryptography.hazmat.primitives.asymmetric import rsa
 from fastapi.testclient import TestClient
-from sqlalchemy import delete
+from sqlalchemy import delete, inspect
 from sqlalchemy.engine import make_url
 from sqlmodel import Session, select
 
@@ -89,6 +89,11 @@ def _clean_engine_rows() -> Generator[None, None, None]:
     between modules bounds it to where the writes actually come from.
     """
     yield
+    # `tests/flow` overrides `db` with a no-op — the engine holds no database
+    # state, so those tests build no schema — and there is nothing to clear
+    # there. Running that directory on its own is how that shows.
+    if not inspect(engine).has_table("run"):
+        return
     with Session(engine) as session:
         for model in _ENGINE_TABLES:
             session.execute(delete(model))

backend/tests/flow/test_pipeline.py

@@ -206,3 +206,150 @@ def test_only_advisory_codes_are_flagged_advisory():
 
     assert hook.advisory is True
     assert cycle.advisory is False
+
+
+def test_a_producer_that_cannot_run_does_not_strand_its_consumer():
+    """One wave, two producers of one consumer, and one of them never ready.
+
+    The house's shape: a battery reading wakes the boiler arbiter and the
+    watering-pump trigger in the same wave, and the DMX encoder reads both. The
+    pump waits on a pulse that only exists at 02:00, so it is never ready — and
+    passing over it used to leave the encoder unreachable, which put every
+    boiler and plug command into its message and no further.
+    """
+    ran = []
+
+    power = make_node(
+        "cerbo", "power", lambda params: {"batt_v": 50.3}, provides=[spec("batt_v")]
+    )
+
+    def arbitrate(batt_v, params):
+        ran.append("boiler")
+        return {"boiler_on": 1.0}
+
+    boiler = make_node(
+        "arbiter",
+        "boiler",
+        arbitrate,
+        requires=[spec("power.batt_v")],
+        provides=[spec("boiler_on")],
+    )
+
+    # Woken by the same wave; `pump_for` has never been published.
+    pump = make_node(
+        "pump_run",
+        "plugs",
+        lambda batt_v, pump_for, params: {"pump": 1.0},
+        requires=[spec("power.batt_v"), spec("plugs.pump_for")],
+        provides=[spec("pump")],
+    )
+
+    def encode(boiler_on, pump, params):
+        ran.append("encoder")
+        return {"dmx_boiler": boiler_on}
+
+    encoder = make_node(
+        "switches",
+        "dmx",
+        encode,
+        requires=[spec("boiler.boiler_on"), spec("plugs.pump")],
+        provides=[spec("dmx_boiler")],
+    )
+
+    pipeline = Pipeline(nodes=[power, boiler, pump, encoder])
+    pipeline.state["plugs.pump"] = 0.0
+
+    power.inject()
+
+    assert ran == ["boiler", "encoder"]
+    assert pipeline.state["dmx.dmx_boiler"] == 1.0
+
+
+def test_a_quiet_producer_does_not_veto_a_noisy_sibling():
+    """Two report-by-exception producers, one consumer, and only one with news.
+
+    The house reads both boilers into one DMX encoder through `rbe` nodes. The
+    kitchen boiler is unchanged almost always, so it returns nothing — and
+    while that held the encoder's dependency count up, the main boiler's
+    command reached its message and got no further.
+    """
+    ran = []
+
+    power = make_node(
+        "cerbo", "power", lambda params: {"batt_v": 50.3}, provides=[spec("batt_v")]
+    )
+    water = make_node(
+        "water_changed",
+        "boiler",
+        lambda batt_v, params: {"water_boiler": 1.0},
+        requires=[spec("power.batt_v")],
+        provides=[spec("water_boiler")],
+    )
+    # Unchanged, so its rbe publishes nothing this wave.
+    kitchen = make_node(
+        "kitchen_changed",
+        "boiler",
+        lambda batt_v, params: None,
+        requires=[spec("power.batt_v")],
+        provides=[spec("kitchen_boiler")],
+    )
+
+    def encode(water_boiler, kitchen_boiler, params):
+        ran.append("switches")
+        return {"dmx_water_boiler": 255.0 if water_boiler else 0.0}
+
+    encoder = make_node(
+        "switches",
+        "dmx",
+        encode,
+        requires=[spec("boiler.water_boiler"), spec("boiler.kitchen_boiler")],
+        provides=[spec("dmx_water_boiler")],
+    )
+
+    pipeline = Pipeline(nodes=[power, water, kitchen, encoder])
+    pipeline.state["boiler.water_boiler"] = 0.0
+    pipeline.state["boiler.kitchen_boiler"] = 0.0
+
+    power.inject()
+
+    assert ran == ["switches"]
+    assert pipeline.state["dmx.dmx_water_boiler"] == 255.0
+
+
+def test_a_consumer_of_only_quiet_producers_still_does_not_run():
+    """The other half of it: freeing a consumer is not the same as running it.
+
+    Nothing it reads was refreshed, so it must stay put — otherwise every wave
+    would re-run the whole graph on values it has already seen.
+    """
+    ran = []
+
+    power = make_node(
+        "cerbo", "power", lambda params: {"batt_v": 50.3}, provides=[spec("batt_v")]
+    )
+    quiet = make_node(
+        "changed",
+        "boiler",
+        lambda batt_v, params: None,
+        requires=[spec("power.batt_v")],
+        provides=[spec("water_boiler")],
+    )
+
+    def encode(water_boiler, params):
+        ran.append("switches")
+        return {"dmx_water_boiler": 255.0}
+
+    encoder = make_node(
+        "switches",
+        "dmx",
+        encode,
+        requires=[spec("boiler.water_boiler")],
+        provides=[spec("dmx_water_boiler")],
+    )
+
+    pipeline = Pipeline(nodes=[power, quiet, encoder])
+    pipeline.state["boiler.water_boiler"] = 0.0
+
+    power.inject()
+
+    assert ran == []