The layout modules moved to library when they were promoted, and three of my
files still named the old paths: the two new whiteboard components, which were
written before the move landed, and the geometry check, which was written after
it and still copied the old import from its neighbours.
GiBoundedSet also carried an unresolved conflict — markers and all — committed by
a cherry-pick loop of mine that resolved generated output automatically and swept
the source conflict along with it. The file had both imports of the same symbol,
one of them pointing at a deleted path. It parsed, so the SFC check passed; only
the bundler would have caught it, and only at the point where it could not
resolve the file.
The lesson is about the loop, not the file: resolving one class of conflict
automatically is fine, but `git add -A` afterwards does not distinguish the
conflicts you meant to resolve from the ones you did not. A loop that stages
everything needs to refuse when a marker is still present.
Three properties, each with the arm that catches its own defect: the bounded
set's gap survives projection, the drawing stays inside the Mercator clamp, and
a radius expressed in map units doubles with every zoom level.
The first arm taught me something I had assumed the opposite of. It narrowed the
gap to a tenth of a percent expecting the margins to go negative. They stayed
positive: the projection is conformal, so it preserves the ratio exactly, and a
narrow gap survives just as an eight percent one does. There is no distortion for
it to be eaten by.
So "the gap survives projection" is close to a tautology, and a check resting on
it alone would look like a guard while testing almost nothing. What can actually
fail is the ordering of the constants, and that is what the arm now poisons. The
narrowing case is kept as a passing assertion rather than deleted, because the
fact that it is safe is worth stating: the boundary cannot be eroded by the
projection, only by someone editing the numbers.
The clamp arm holds for every chart at once. The ceiling belongs to
extentFraction alone, not to a chart's extent — the scale is extentFraction over
extent and the outermost point sits at the extent, so the product is always the
fraction. Asserted across four extents, identical to three decimals.
