`math_dialog_sync_form()` wrote the label and then moved a node whose source
names an unacquired channel -- a mutation that changes what
`math_dialog_problem()` reports. With the sync re-entry now guarded, the nested
call that used to repair the label is suppressed, so the line kept describing a
source that had just been fixed and left `Apply` insensitive until the next
mutation. The reconcile moves above the write and the dropdown reuses its list.
A review of the whole node editor. The hit test measured the distance to the
24 curve samples rather than to the segments between them, so a wire spanning
several rows was unpickable between two samples -- the probe now places its
boxes 280 units apart and prints the nearest sample's own 8.4 against a 3.0
tolerance, which the point test would have missed. A refused connection said
nothing: the message is now carried in `MathDialog::refusal` and shown once by
the single writer of the label, and a self-wire is refused through the real
drag-end path instead of only through `math_connect()`.
Two defects were found only by the new assertions. `math_dialog_sync()`
re-entered itself -- `gtk_drop_down_set_selected()` emits `notify::selected`
for a programmatic set too, and the handler answers by syncing again, which
consumed the refusal before it could be drawn -- so the body is now guarded
one level deep. And a deleted node left `selected_wire` naming an index that
afterwards belongs to a different wire, so `Delete` cleared an input on the
wrong node.
A node is placed in the first free grid cell rather than at the end of the
list's own cell, so a node added after a delete no longer lands on top of a
survivor; the label ellipsizes with a tooltip rather than wrapping, because a
wrapped line makes the dialog's height depend on the text in it.
Each invariant records what went wrong rather than only the rule: a port hit
that lost its node, a hit test at the identity view that asserts nothing, a
`Delete` that must not fall through to the selected node, and a column pitch
too narrow for a wire's own tread. The warning baseline drops to four.
The file was 1967 lines and is auto-loaded into every context, so every
session paid for the whole of it to reach one invariant. It now carries the
project's goal, the three facts that are always relevant, and a table of
contents; the body is fourteen files under docs/claude/ reached by link
rather than by import, so nothing is loaded until it is asked for.
The content is moved verbatim -- the only edits are each file's own header
and the cross-references that became cross-file ("see the invariant below"
is now a link to the file that owns it).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>