Evaluation cache: every feature evaluation is kept by a key of its own inputs, the document context it reads and a digest of the model it starts from (bodies identified by the evaluation that made them, kept while passed through), shared with previews and scratch copies; setting a value back, undo, redo and repeated evaluations reuse results (a 20 × 20 patterned plate builds in 1.7 s instead of 7.5 s; undo/redo of a parameter edit 0 ms); cached and from-scratch evaluation compared in a test; numbers in docs/perf.md (solvecraft-cli bench-edit). Designs read now always get feature input names and occurrences filled in

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

docs/perf.md

@@ -38,3 +38,46 @@ What changed: rows scrolled out of view only reserve their height. They register
 and paint nothing (no text layout, icons or eye/fold buttons), so the cost follows the rows on
 screen rather than the rows in the tree. Scrolling, Find in Browser and drag and drop still see
 every row's place.
+
+# Recompute performance
+
+`solvecraft-cli bench-edit <script> <param> "(<old>) * 1.02"` builds a design from its script
+(timing the build), then times a parameter edit, setting the parameter back to its old
+expression, undo and redo. Each cell is before → after the evaluation cache, with the number of
+features recomputed in parentheses. Release build, on a machine shared with other build jobs (load average about 45; the
+times vary by ±50 % run to run, so compare the recompute counts and the zeros). "Early" edits a parameter of the
+first sketch or feature, "late" one of the last feature.
+
+| Design | Edit | Build | Edit | Set back | Undo | Redo |
+|---|---|---|---|---|---|---|
+| sample plate, 20 × 20 pattern | early (`width`) | 7587 ms (10) → 1764 ms (10) | 7969 ms (10) → 1691 ms (10) | 7557 ms (10) → 0 ms (0) | 6534 ms (0) → 0 ms (0) | 4570 ms (0) → 0 ms (0) |
+| sample plate, 20 × 20 pattern | late (`d9`) | 7870 ms (10) → 1699 ms (10) | 3944 ms (1) → 812 ms (1) | 4039 ms (1) → 0 ms (0) | 1464 ms (0) → 0 ms (0) | 1398 ms (0) → 0 ms (0) |
+| oracle 58 phone stand | early (`d1`) | 163 ms (6) → 140 ms (6) | 228 ms (5) → 140 ms (5) | 171 ms (5) → 0 ms (0) | 158 ms (0) → 0 ms (0) | 130 ms (0) → 0 ms (0) |
+| oracle 58 phone stand | late (`d4`) | 144 ms (6) → 195 ms (6) | 118 ms (1) → 118 ms (1) | 145 ms (1) → 0 ms (0) | 149 ms (0) → 0 ms (0) | 187 ms (0) → 0 ms (0) |
+| oracle 59 enclosure base | late (`d8`) | 11582 ms (11) → 11179 ms (11) | 5772 ms (1) → 5742 ms (1) | 5606 ms (1) → 0 ms (0) | 6023 ms (0) → 0 ms (0) | 6119 ms (0) → 0 ms (0) |
+| oracle 60 pipe flange | early (`d1`) | 8137 ms (7) → 8348 ms (7) | 7569 ms (6) → 10143 ms (6) | 8354 ms (6) → 0 ms (0) | 8607 ms (0) → 0 ms (0) | 10034 ms (0) → 0 ms (0) |
+| oracle 60 pipe flange | late (`d6`) | 7661 ms (7) → 11990 ms (7) | 67 ms (1) → 361 ms (1) | 69 ms (1) → 0 ms (0) | 84 ms (0) → 0 ms (0) | 66 ms (0) → 0 ms (0) |
+| oracle 61 shaft keyway | early (`d1`) | 1723 ms (6) → 3016 ms (6) | 1785 ms (5) → 2745 ms (5) | 1760 ms (5) → 2323 ms (5) | 1667 ms (0) → 0 ms (0) | 1719 ms (0) → 0 ms (0) |
+| oracle 61 shaft keyway | late (`d4`) | 1905 ms (6) → 2247 ms (6) | 1734 ms (1) → 2101 ms (1) | 1682 ms (1) → 0 ms (0) | 1719 ms (0) → 0 ms (0) | 1876 ms (0) → 0 ms (0) |
+| oracle 62 heat sink | early (`d1`) | 382 ms (6) → 643 ms (6) | 362 ms (5) → 697 ms (5) | 233 ms (5) → 568 ms (5) | 245 ms (0) → 0 ms (0) | 360 ms (0) → 0 ms (0) |
+| oracle 62 heat sink | late (`d5`) | 479 ms (6) → 688 ms (6) | 270 ms (1) → 657 ms (1) | 321 ms (1) → 0 ms (0) | 413 ms (0) → 0 ms (0) | 283 ms (0) → 0 ms (0) |
+| oracle 63 hinge knuckle | early (`d1`) | 1305 ms (8) → 1671 ms (8) | 1329 ms (7) → 2397 ms (7) | 1971 ms (7) → 0 ms (0) | 1705 ms (0) → 0 ms (0) | 1321 ms (0) → 0 ms (0) |
+| oracle 63 hinge knuckle | late (`d4`) | 1430 ms (8) → 2072 ms (8) | 1387 ms (1) → 2073 ms (1) | 1480 ms (1) → 0 ms (0) | 1192 ms (0) → 0 ms (0) | 1035 ms (0) → 0 ms (0) |
+
+What changed: every feature evaluation is cached by a key made of the feature's own inputs
+(definition and parameter values), the document context it may read (construction planes,
+sheet metal and plastic rules, components) and a digest of the model it starts from, in which
+each body is identified by the evaluation that produced it (bodies a feature passes through
+unchanged keep their identity). The same feature on the same inputs is never evaluated twice:
+setting a value back, undo, redo, a preview followed by the same command, and the repeated
+evaluations while a script builds the design all reuse earlier results. The cache is shared by a
+model and its copies (previews, scratch sessions) and keeps the last 4096 results.
+
+An edit still recomputes the edited feature and every later feature whose starting model
+changed; in these parts every later feature works on the edited body, so early edits recompute
+almost everything, as they must. `cached_evaluation_matches_from_scratch` checks that cached and
+from-scratch evaluation give the same models (bodies, volumes and areas to 1e-6, topology,
+errors) through edits, suppression, roll-back, undo and redo. Setting a sketch dimension back
+can still recompute (oracle 61, 62): solving the sketch moves its points by rounding noise, so
+its inputs are not exactly the old ones. Oracle 59's first parameter edit fails (a recipe
+expression the bench's `* 1.02` can't scale) and is left out.