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code" would have enforced a rule now withdrawn.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.
The tiers were settled and the product was named, but the repositories
themselves existed only in a research sketch. That had already caused two
problems.
ADR 0029 makes the lab phase 0 of the migration and could not say where it
lives, because no record named a repository.
And the sketch contradicted an accepted record: it listed mesh-hq while
ADR 0028 had decided novox/hq and explicitly rejected that name. A design
resting on research is resting on something that can change without a
decision. Corrected in the research too.
The naming rule, which both earlier records implied and neither stated: a
repository belonging to a product carries that product's prefix; a
company-scoped one does not. That is why this repository is hq and the
mesh's are mesh-*.
Seven repositories recorded — host, substrate, control, surfaces, sdk, lab,
and this one. The lab gets its own: it ships to nobody, outlives any single
tier, and drives virtualisation on a workstation, which nothing else does.
Inside the host it would couple development tooling to a shipped
component; inside the control plane the bootstrap scenario would depend on
a tier that does not exist when it is needed.
Tier 4 is deliberately not decided. Whether the catalogue is one
repository, one per domain or one per application stays open from ADR 0015
and is blocked on research 005 — how many repositories hold domains cannot
be answered before knowing what the domains are. mesh-catalog appears in
the sketch and is not decided by this record.
The cost is stated rather than glossed: seven release cadences where there
is one, and cross-repository changes that used to be one commit.
jschoubben