Every surviving carrier now owns its artifacts: checked mkdir/mkdtemp/
fopen acquisition, one all-exit cleanup funnel per carrier, ENOENT-
tolerant checked unlinks, exact-path deletion (rm -rf only for an
owned pid-keyed dir or a .sepwork beneath one), and cleanup failure
fails a passing carrier without overwriting its diagnostic. In the
same pass the carriers adapt to the driver contract this branch lands:
--sep and WW_PKGCACHE are gone, -S and the /tmp/ww_run_<pid> scratch
contract are asserted, and rows whose runtime or reject coverage moved
to test/wcc/data fixtures or test/lang @test owners are trimmed to the
byte/artifact/diagnostic observations only they can make.
Repair and adaptation ride together because most files interleave both
in the same hunks; splitting would manufacture intermediate carrier
states that never existed and cannot run against either driver.
The driver searchpath is srcd-first (srcd = the entry file's directory).
A co-located black-box test lib/<mod>/<mod>test.ww makes srcd=lib/<mod>,
so resolving `import <mod>` hit the sibling-FILE branch lib/<mod>/<mod>.ww
and folded it inline into the consumer unit under the wrong module tag
("package <mod> does not match import path <importer>") — 7 lib-run tests
fail under separate compilation. The combined amalgamator tolerated the
co-location; only sep surfaced it.
Resolve a package directory-first: walk ALL searchpath entries for a
directory match, and only fall back to a file match if no directory
exists anywhere. A dir-package now beats a same-named sibling file (fixes
the self-named shadow), while a leaf package with no directory (e.g.
lib/encoding/hex) still resolves via its file. This realizes the driver's
"a module is the directory" intent; the originally-specced per-directory
suppression was rejected because it broke leaf packages (rob-pike). Both
stages (cmd/ww/main.c + selfhost twin). The dir-beats-earlier-file
precedence change is latent and loud-failing (#101).
Move-set: ww + ww_ww (driver) only; w6c_ww/wwdump_ww/w6a_ww/w6l_ww HOLD.
Gate: test/wcc/989_coloimport_sep.c (table-driven, both stages).
