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.
build_one/buildone gain an explicit objstem: 'ww build -o X' derives
main.{combined.ww,s,o} beside X; 'ww run' uses its per-pid /tmp stem;
default no--o stays next-to-source (load-bearing for the make regen of
tracked combined.ww and the freshness gate). Realizes the redirect TODO
in 995_self_rebuild.c. Kills the concurrent-test torn-read race on
selfhost/cmd/<tool>/main.* (the 991 transient). 993/995/949 pass -o
into their per-pid workdirs; 949's '-o /dev/null' relied on the old
driver ignoring -o (audited: the only live driver case). Atomic
combined write (os.rename) deferred to its own commit - lib/os lacks
rename and that addition is an import-floor regen.
Both driver twins: an import that neither locates as a file nor is
satisfied by an inline 'package <name>' declaration in the unit is now
fatal "ww: cannot find package <name>" (was a silent skip that masked
dead imports and typos). The inline scan is a new every-line helper on
the uncapped comment-skip core - peekpackage stops at the first decl,
and single-file multi-package fixtures declare several. 949 pins both
branches (miss->fatal, inline->build+run); 993 adds ww_ww parity.
