A browser page with controls on one side and the cross section on the other. Three separately classed layers: printed material, the cavities the stock passes through, and the stock drawn inside its cavity so the fit gap is visible. Under it the report and the design record, so the identity of a part is visible while tuning rather than discovered afterwards. Standard library only, no framework, no build step, no new dependency.
Binding comes from /etc/mechcomp/mechcomp.env, which already declared 10.20.0.10:8770. An earlier draft invented a port on 0.0.0.0, which would have placed a second unproxied plaintext copy beside the proxied one. The fallback with no env file is loopback, never every interface: behind a proxy, binding too narrowly fails loudly as a 502 and too widely fails silently as an open service.
Controls are filtered to the selected profile, with no catch all group. A knob that moves nothing is worse than an absent one.
Renderer tests assert what an eye cannot: the vertical flip happens exactly once, holes render as holes, and the cavity is larger than the stock inside it. Seven mutations on the renderer, all caught.
Result gains a record field with a default. Nothing existing moves and the report dict is untouched, so all 123 oracle cases are unmoved at 506 passed. A rejected profile still raises before this point and gets no record, which is correct because there is no model to preserve.
The record learns the stock and fit from the Geo the build actually used, so it describes what was built rather than what was asked for. Those agree today and the record will keep saying so if they ever stop.
code_revision resolves once per process from MECHCOMP_REVISION, then git rev-parse, then unknown. Never a guess: unknown tells you the part may not be reproducible, while a plausible wrong sha would send someone to the wrong commit. A dirty tree is reported as such, since a model built from uncommitted edits cannot be regenerated from a revision alone. Caching matters because assemble runs 123 times in the suite and would otherwise shell out to git twice per build.
The end to end test builds a part, renders its record, parses it back from nothing but the text, rebuilds from the parsed parameters, and asserts the report is identical key for key across five profiles. If that fails the record is a description rather than a recipe.
Method correction. The mutation harness had been letting pytest write bytecode, and a write landing inside one mtime tick could be masked by a stale pyc. That made one real defect appear to survive and, more importantly, means every mutation result reported earlier in this work was optimistic by an unknown amount. Rerun with bytecode disabled, all nine mutations caught. The earlier sets are worth rerunning under the corrected method.
A parametric compiler is meant to be tuned: print, measure the print, adjust, print again. That loop also destroys the value of everything already printed, because once a clearance moves the parts on the bench become unidentifiable and unreproducible. Configurability and reproducibility conflict unless something records what each part was made from.
The record carries the fully resolved parameter set at full precision, the stock and fit lines with whatever provenance exists, the code revision and the toolchain. Plain text, one fact per line, readable without this software.
It is deliberately not built from the report. geom.report rounds to six significant figures because that is what echo printed and the oracle records what was printed. A part cannot be regenerated from SECTION_AREA_MM2 equals 135.574. Inputs reproduce, outputs confirm: reported values are carried separately as verification, to be checked with a caliper against the actual part.
Two identities. input_id covers family, profile and parameters, the design intent. build_id adds code revision and toolchain. Shapely and GEOS are in build_id because boolean results on near degenerate geometry can shift between GEOS releases, which is the F-034 mechanism, and a record omitting them could not explain why the same numbers produced a different part. Timestamp, note and verification values are excluded from both.
Not on the build path. No profile imports it, so the frozen oracle cannot move. Twelve mutations tested and caught, including two defects of mine: the record carrying only overrides rather than the resolved set, and the toolchain never reaching build_id.
geom.records no longer computes the section, cavity or laminae. It calls mechcomp.stock, so the shape of a piece of stock is defined once. All 123 oracle cases unmoved: 482 passed. stock.py also becomes a leaf module, ending an import cycle with geom that resolved only by accident of ordering.
Three defects in f5651d3 corrected. Provenance raised on an empty source, which made an unattributed dimension unrepresentable and blocked the ordinary use of the tool: type what the caliper reads, print, measure the print, adjust. Provenance now records and travels with the output. Fit refused negative clearance on the argument that interference is not assemblable, which is a design judgement and not the compilers to make. Interference is now computed and reported. CATALOGUE read as a whitelist and is documented as starting points, with a test asserting an entry built from nothing is as valid as one pulled from the dict.
emt_template takes the diameter, fit, designation and note from the caller. There is no standards table and no lookup. A parametric compiler cannot require its subject to be catalogued before it will run.
STOCK.md section 5 amended, since the refusals were implementing it. An entry without provenance no longer fails to ship, it ships labelled unattributed. The principle that a number must not appear from nowhere looking authoritative survives; the door does not.
Tests compare records and stock against a hand transcription of the reference rather than against each other, which would be tautological after delegation. Mutation testing found four gaps before landing: a dropped lamina stacking offset, emt_template silently ignoring its fit argument, describe discarding the note exactly when provenance was unverified, and a guard on float arithmetic that asserted a tautology.
The compiler describes off-the-shelf hardware and generates the printed part that encloses, interfaces with, or augments it. The pallet strap is not the subject of the library, it is the first entry, and it was inlined into Geo rather than described. STOCK.md states what every entry must declare: designation, section, nominal versus actual, fit, stock tolerance, provenance.
Geo conflates three things. Width, thickness and count are the stock. Clearance is the fit, a property of the joint. The wall thicknesses are the printed part policy. This commit names the first two and leaves Geo untouched, so no profile imports the new module and the frozen oracle cannot move.
test_stock.py proves faithfulness by exact float equality against geom.records across 36 parameter combinations, 5 placements and 3 face modes. Mutation tested before landing: reversed vertex order, halved clearance, dropped lamina offset and a naive round cavity are each caught.
Round cavities are circumscribed rather than inscribed. A vertices on circle polygon lies inside the nominal diameter and bites into it by r times one minus cos 180 over n, about 9.6 micron at 9 mm radius and 48 facets, which is enough to stop a press fit. Conduit is deliberately absent from the catalogue until a measurement or citation exists.
The oracle records six significant figures, so the last digit of an area near 200 mm2 is worth 0.001 mm2. Every measured disagreement between port and reference is one, two or three units in that place. SECTION_AREA_MM2, VOLUME_MM3 and MASS_G are now bounded at 8 ULP of the expected value. Everything that positions material keeps the declared 1e-4 mm and remains exact in all 123 cases.
Option 1 scope kept, derivation rejected on measurement. Max |dA|/P over the accepted set is 1.434e-05 mm, one seven-hundredth of the 0.01 mm criterion, so a perimeter x 0.01 bound would have run 1800 to 4500 times the worst real discrepancy and caught nothing. Perimeter also anti-correlates with the error.
Suite 468 passed, 0 failed. The 30 expected failures are resolved, not suppressed. Mutation tested before landing: worst case uses 37.5 percent of its bound, 12 ULP offsets and 1e-4 relative scalings are caught in all 113 cases, 1e-6 and 1e-5 correctly are not.
Adds docs/ACCEPTANCE.md as the specification. Adds F-036, the venv interpreter error, same class as F-035. Corrects the F-034 per-profile distribution to Three-Fin 10, Y 7, A Frame 6, Rectangle 5, T 1, Four-Fin 1, which sums to the stated 30.
The PROFILE record, centred assembly, and three complete arrangements:
ring, spokes, fins. Each written for N members, exercised at N=3 and N=4.
Failure travels as an empty profile carrying one failing check, as in the
reference, so profile rejections and universal-check rejections stay in
one order-sensitive list and the first failure is what surfaces.
The section is cleaned before it is measured, not after. A Three-Fin
section carries 17 collinear vertices from exact butt joints; they are
harmless in 2D and leave zero-area triangles the tessellator cannot
resolve, so measuring first would report on geometry that is not what
gets extruded.
Centred now carries the shifted members. Measuring a shifted shell
against unshifted members reports every cavity as escaping the envelope,
a leak of the whole cavity area from geometry that is fine. That trap
caught me while smoke testing, so the opportunity is removed rather than
documented.
Verified against the oracle where the fillet does not affect the result:
SPOKE_RADIUS_MM 9.1713, FIN_CORE_SIDE_MM 13.4028, FIN_SETBACK_MM
3.77783, FIN_JUNCTION_WEB_MM 2.29919, RING_CORNER_R_MAX_MM 2.87663, the
ring edge vector, and both envelope dimensions all match to the recorded
digit. The solvers are right.
OPEN: with a junction fillet of 1.5 the Y section area is 135.572973
against a recorded 135.574, off by 0.001027 and just past the area
tolerance, while every other quantity for that case matches exactly.
Either the generator fillet default is not 1.5, or there is a difference
of about seven parts per million concentrated in the fillet. The
generator settles it.
35 tests. Nine mutations, two of which found real gaps: nothing asserted
that cleaning removed anything, and the spoke zero-fillet check was
untested.
Oracle acceptance still skips; 236 unchanged.
Checks as values, the five universal checks, metrics, ProfileRejected,
and the report block. Completes the shared layer; only the profiles and
build() remain.
Report numbers are rounded to six significant figures on the way out,
matching OpenSCAD echo, which is C %g at default precision. The oracle
records what OpenSCAD printed, not full-precision geometry.
This is load bearing rather than cosmetic. VOLUME_MM3 ends in _MM3, so
test_oracle.py compares it at the lengths tolerance of 1e-4 and not the
areas tolerance of 1e-3. Volume is section area times a 100 mm length,
so an unrounded port reporting 13557.402 against a recorded 13557.4
fails by twenty times the tolerance while being geometrically correct.
Verified against the oracle: across all 113 accepted cases the recorded
volume equals the rounded area times length to within 3.6e-12, which
holds only if volume is computed unrounded and rounded at print. That is
what this layer does.
The consequence is that geometry must agree with the reference to better
than one part in a million before rounding. Near a rounding boundary a
smaller error can still tip the last digit, and that will show up as a
single case failing by one unit in the last place rather than as
something mysterious.
28 tests. Nine mutations, all caught first pass, including rounding to
decimal places instead of significant figures and computing volume from
the already-rounded area.
Oracle acceptance still skips; 236 unchanged.
Face lines, structural butt joints, hull caps, concave fillets, the
derived bore, ring fit, ring envelope and section assembly. N-generic
throughout, as the reference is.
Junctions are structural, not cosmetic: one sleeve runs through its
neighbour and is cut flush against that member the far surface, so the
two share a full-width overlap whether or not a fillet is applied on
top. The bore is derived from the members own inside-wall lines rather
than a separately scaled shape, which is what makes the declared inside
wall exactly what remains beside each cavity.
43 tests. Mutation testing found two of the reference own warnings to be
load-bearing and untested by me. A bore that has turned inside out can
carry over a square millimetre of area, so the area guard alone accepts
it and only the interior-side test rejects it. And the ring fit really
does have a spurious lower branch: a thin triangle meets a 1.2 mm web at
relative scale 0.425, where members overhang their own corners and the
solve looks converged. Both now covered.
A third mutation was malformed on my part rather than a gap -- cutting
the cavities twice is idempotent -- and was replaced with one that does
change behaviour. Nine mutations caught.
Oracle acceptance still skips; 236 unchanged.
Booleans, decomposition, area, simplicity, hull, bounds, mitred offset
and vertex cleaning. Booleans go to GEOS, which is the reason Shapely was
chosen. The decomposition does not.
BOSL2 region_parts counts by nesting parity, not connectivity: a path
takes a level from how many others contain the midpoint of its first
edge, even levels are outer boundaries, their odd children are holes.
SECTION_PARTS == 1 is an exact assertion, and Shapely agreeing with that
count is a coincidence that holds for well-formed input and not
otherwise, so the decomposition is transcribed and both the part count
and the area derive from it.
is_region_simple is treated as a manifold precondition rather than a
diagnostic. An outline that touches itself measures perfectly and cannot
be tessellated, so it must fail here and not at export.
Developed against Shapely 2.1.2 / GEOS 3.13.1, matching CT 100. Boolean
results on near-degenerate geometry can shift between GEOS releases; if
the oracle ever disagrees by one part after an upgrade, look there first.
39 tests, all arithmetic on rectangles. Mutation run found a real gap:
nothing distinguished on-boundary from outside in the nesting probe until
a shared-edge case was added. Eight mutations now caught.
Oracle acceptance still skips; 236 unchanged.
Shapely has no corner rounding, so the round_corners -> _circlecorner ->
arc -> segs chain is transcribed from BOSL2 at the pinned commit
92d697c2, read from source rather than recalled. Also deduplicate,
path_merge_collinear, is_collinear and approx, which the cleanup path
depends on.
Segment counts are contract, not a quality setting. An arc becomes
straight segments and the count sets the enclosed area, compared against
the oracle at 1e-3 mm2 -- and the extruded solid is those segments, so
this is the definition of the surface. Both generators set $fn = facets
with facets = 48 and no oracle case overrides it, so segmentation
depends on swept angle alone. A right angle gives 12 points.
round_corners raises where BOSL2 asserts, rather than clamping: silently
fitting a roundover the reference refused would diverge without any
visible failure. sb_corner_radii exists to derive safe radii up front.
33 tests. The exact-fit boundary raises rather than passing, because
tan(45) is under 1 in both languages -- a test asserting the tidy
behaviour would have looked right and been wrong. Mutation run found a
real gap: nothing exercised the three-point floor on blunt corners until
a 170-degree case was added. Seven mutations now caught.
Oracle acceptance still skips; 236 unchanged.
Vectors, GEO and MEMBER records, member placement, sleeve and cavity
paths, exact polyline distance, corner-radius derivation, and the
monotone solver. Direct translation of legacy/openscad/lib/sb-geom.scad
at rev 8.0.0.
Angles stay in degrees, matching OpenSCAD, so every expression reads the
same as its source line. The 44 solver iterations, the 0.999 and 0.98
scale factors, the 0.05/179.95 cutoffs and the 1e9 sentinel are
reproduced exactly: they shaped the frozen oracle.
Region operations are not included -- they need a 2D boolean kernel and
follow with the Shapely layer.
49 unit tests, none of which touch the oracle. Harness proven by
mutation: radians for degrees, a shortened solver, a dropped scale
factor, a skipped crossing test and a flipped offset sign are each
caught. Oracle acceptance still skips; 236 unchanged.
Reference implementation of the strap-beam generators at revision 8.0.0, kept
so the acceptance oracle can be regenerated. Not a live target; the running
application has no OpenSCAD dependency.
The oracle holds 123 frozen cases, 113 accepted and 10 rejected, produced by
OpenSCAD 2021.01 with BOSL2 at 92d697c2. The ten rejections are part of the
contract: a port that accepts them is wrong.
tests/test_oracle.py specifies the port API and was written before the port,
so the interface follows from what must be verified rather than what is
convenient to implement. Proven by adversarial stub: a build() that rejects
everything passes all 10 rejection tests and fails all 226 acceptance tests.
TheRON
civicus-build