Three things from walking a real dev cycle through 0063, all of which Jochen
caught by pushing on where I had glossed.
0064 -- a build edge is a third kind. Research 011 established presence and
instantiation, and both are RUNTIME edges: they answer what a module needs in
order to run. Delivery needs a different question -- what has to be rebuilt when
this changes -- and that relationship is fixed inside an artifact rather than
negotiated when it runs. So the graph as designed could not drive delivery,
which is the real reason 0063 was not approvable.
It is derived rather than declared, read from what a module actually imports,
because a declared list and the imports it describes drift and the imports are
the true ones. The runtime edges stay declared, and that asymmetry is not an
inconsistency: a runtime edge is an intention somebody has, a build edge is a
fact about code that exists.
It also makes design quality measurable. A module with many inbound build edges
is one whose every change is expensive, and the current shared library is
exactly that -- nobody could see it because nothing drew the edges.
0065 -- the core library is the mesh's domain. Jochen disagreed with 0030's
"types, not behaviour" and was right: that guard is aimed at the wrong thing. A
library everything depends on is a hub whether it holds types or code, and the
fan-in is what makes a change expensive. So types ship with the module that
owns them -- trading one wide edge for several narrow ones -- and the core
library holds what is true of the mesh regardless of context, which research
011 already found: a module, a node, an assignment.
The test is "would this still mean the same thing in a context that had never
heard of the one it came from". A node does; a pipeline stage does not.
Domain-driven is the point rather than the label: "who else might want this"
always answers yes, which is how the current one grew.
And it changes the check for the better. "The build output contains no runtime
code" would have enforced a rule now withdrawn. Inbound build edges is a
measurement rather than a prohibition, and it is visible while a hub is forming
rather than after.
0063 revised on both counts, plus a third: I had written "the lab judges it" as
though that were a step. A lab run takes tens of seconds, occupies a VM, and
fails for environmental reasons -- and a shared-library change produces dozens.
One expensive non-deterministic gate fails both ways, and neither failure looks
like itself. Verdicts are now tiered, and a run that failed environmentally is
explicitly not a verdict.
0063 also now carries what must exist before it can be implemented, rather than
leaving that to be discovered.
Jochen: don't rebuild the current coordinator, use it as a pitfall list. That
reframed the last open question rather than answering it.
0058 stopped deploy being a stage that pushes to nodes, and said plainly what
it did not fix: detection. A merge that created no pipeline, and nothing said
so. That is not a defect in the detector -- it is what happens when correctness
depends on an event ARRIVING.
0063 applies 0058's move one level up. The control plane holds what source
exists and what has been built from it, and builds the difference. A change
becomes a build because source is ahead of artifacts, which is a comparison
answerable at any moment. An event makes it fast; nothing makes it necessary,
so a missed webhook costs latency and cannot cost correctness.
The mesh becomes one idea at two layers: the control plane reconciles artifacts
against source, the host reconciles machine state against declarations. The
pipeline as a state machine disappears, and with it the stage list that a
verify step was once omitted from.
That reframing answered the three questions still open in 008, so it graduates
with all six closed. A deployed state is two comparisons rather than an event.
A verdict is about an ARTIFACT and gates whether it may be declared -- sharper
than the question expected. And "before self-hosting" mostly dissolves, because
a reconciler needs source and artifacts as bindings where a pipeline's stages
name their targets.
Four costs recorded, and one is a real risk rather than a trade: a reconciler
that cannot reach its target retries forever, and without something noticing,
the failure is silence -- the exact fault this removes, reintroduced elsewhere.
Also named: the run identity people actually use is lost, and "did my change go
out?" needs a replacement or this will be worse to live with than what it
replaces, whatever its properties.
jschoubben