The wcc test drivers ran `ww build <bare-/tmp src>` with no -o, so the
compiler's <stem>.sepwork scratch landed beside the source and was never
cleaned: unbounded /tmp growth (2195 stale dirs observed) that fills tmpfs
and fabricates phantom test failures + silent harness aborts, and for
in-repo fixture builds leaked .sepwork into the tracked tree.
Each leaking build now writes its source + output inside a per-invocation
tmpdir, passes -o <tmpdir>/<stem> so the .sepwork lands inside it, and
rm -rf's the tmpdir on every exit path -- including fopen-fail and the
expected-fail reject builds (scratch is mkdir'd before the build can fail).
`ww run` and explicit-`-o`/byte-id helpers are left as-is; the 990/993
byte-id comparison logic is byte-for-byte unchanged.
Two items filed separately (this commit holds the no-Makefile / no-main.c
rail):
- #13: a stale <src>.s byte-id readback (749) silently no-ops since
separate-compile emits .s to <ostem>.sepwork/__root.s; documented inline.
- #14: build-system Makefile recipes build selfhost/cmd/*/main.ww with no
-o and leak main.sepwork in-tree (bounded, gitignored; own commit).
One concern -- sepwork leak hygiene -- across 228 drivers; uniform
transform applied per-file and two-round reviewed. make test: all 402
passed, zero net-new /tmp scratch, zero test-driven in-repo .sepwork.
append/insert of a struct-LITERAL value evaluated the literal's field
exprs AFTER the grow, so a field reading the destination (e.g. len(xs))
saw the grown length. Both stages, #263 gate-blind (cs==ww byte-identical,
both wrong — runtime is the only net). #50 fixed the scalar/boxing value
arm; the struct-lit arm still post-grew.
Fix (mirror #50, both stages): resolve the struct, fill the literal into a
fresh per-site scratch (@appendstructscr, sized esz, survives rt_ensure +
nested-append clobber) BEFORE the grow, then copy scratch -> post-grow slot.
The copy uses the precise descending 8/4/2/1 ladder (the proven N_IDENT
struct arm directly below), NOT a raw 8B-word block copy: a struct's size
rounds to maxalign (check.c:916), so a sub-8B struct packs at a 4/2/1B
slice stride and an 8B copy over-writes past the slot — at a power-of-2
capacity boundary that clobbers the adjacent allocation (heap corruption,
both stages). The ladder never reads past esz (no uninit high bytes) nor
writes past the slot; esz=8 stays a single MOVQ (byte-id preserved).
insert() rides by construction: both stages desugar it to append and
re-dispatch into this arm. The #49 aplace path already uses the precise
ladder (verified, not exposed). #59 closes the last composite-value
eval-order hole in append/insert.
Pin: 946_append_structlit_evalorder_run — append / insert / narrow-neighbor
(i32-field at the cap boundary with an adjacent-allocation survival assert)
rows, each base-fail at 39432f7 and post-pass with cs==ww byte-id.
