Self-host M2: native-link bin/vm.php + lib/AOT/Linker.php in spine smoke

[PurHur]

Problem

M2 spine native link is green on master after #2499 / #2502–#2504 (May 2026 harness):

script/apply-patches.sh
BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke
# stdout: compiler_lib_spine_smoke bundle OK
php bin/compile.php -l test/selfhost/compiler_lib_spine_smoke/main.php   # exit 0

Remaining M2 gap: only bin/vm.php is deferred from native-link smoke (SSOT script/bootstrap-spine-deferred-lib.php). Today the spine uses substitute test/bootstrap-aot/vm_run_smoke.php.

Path	Status	Notes
lib/AOT/Linker.php	✅ promoted	#2267 — real require_once in spine
bin/vm.php	🚧 deferred	Execute smoke #2201 after promotion

Coverage: 661 spine require_once / 657 inventory files (php script/bootstrap-spine-count.php); count semantics #2500.

Goal

1. Promote bin/vm.php to real require_once in test/selfhost/compiler_lib_spine_smoke/main.php with native link green
2. $spineNativeLinkDeferred → [] in script/bootstrap-spine-deferred-lib.php
3. Unblock Self-host M2: BootstrapVmDriver native execute smoke (post-#2134 bin/vm.php link) #2201 VM driver execute probe

Gates

Gate	Command	CI env
M2 spine compile+link	BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke	BOOTSTRAP_LIB_SPINE_SMOKE=1
M2 spine lint	php bin/compile.php -l test/selfhost/compiler_lib_spine_smoke/main.php	bootstrap-selfhost-lint.sh
M2 VM -r smoke	BOOTSTRAP_LIB_SPINE_VM_SMOKE=1 make bootstrap-selfhost-lib-spine-vm-smoke	BOOTSTRAP_LIB_SPINE_VM_SMOKE_GATE=1
Coverage	php script/check-selfhost-spine-coverage-sync.php --verbose	SELFHOST_SPINE_COVERAGE_SYNC_GATE=1
Deferred footnotes	php script/check-selfhost-spine-deferred-sync.php	SELFHOST_SPINE_DEFERRED_SYNC_GATE
M4 dry-run	./script/bootstrap-loop-probe.sh --dry-run	BOOTSTRAP_LOOP_PROBE_GATE=1

Files

Piece	Path
Spine bundle	test/selfhost/compiler_lib_spine_smoke/main.php
VM entry	bin/vm.php
Substitute (remove)	test/bootstrap-aot/vm_run_smoke.php
Deferred SSOT	script/bootstrap-spine-deferred-lib.php
Link script	script/bootstrap-selfhost-lib-spine-smoke-link.sh

Done when

• bin/vm.php is a real spine require_once; substitute removed or documented
• BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke stays green
• bootstrap_spine_native_link_deferred() returns []
• Self-host M2: BootstrapVmDriver native execute smoke (post-#2134 bin/vm.php link) #2201 probe can land

Repro

./script/docker-exec.sh -- bash -lc '
  script/apply-patches.sh
  BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke
'

Links

• Self-host M2: php-cfg UnionType parser — compiler_lib_spine_smoke compile fails #2499 ✅ · Self-host M2 slice: native-link lib/AOT/Linker.php in spine smoke (1/2 deferred paths) #2267 ✅ · Self-host M2: BootstrapVmDriver native execute smoke (post-#2134 bin/vm.php link) #2201 execute · Self-host: spine require_once count vs inventory SSOT drift (661/657) #2500 counts
• Epic Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 · M4 Self-host M4: Native gen-2 AOT emit without Zend fallback (post-#1498) #2075