PurHur · PurHur · Jun 16, 2026 · Jun 16, 2026
diff --git a/docs/bootstrap-selfhost.md b/docs/bootstrap-selfhost.md
@@ -1,6 +1,6 @@
 # Self-host bootstrap roadmap
 
-**Gen-0 without Zend:** `BOOTSTRAP_M5_NO_ZEND=1 make bootstrap-selfhost-link` installs `prelinked/bootstrap-gen0/bin-compile-aot` and links `compiler_minimal` without `php bin/compile.php` ([#3053](https://github.com/PurHur/php-compiler/issues/3053)).
+**Gen-0 without Zend:** `BOOTSTRAP_M5_NO_ZEND=1 make bootstrap-selfhost-link` installs `prelinked/bootstrap-gen0/bin-compile-aot` and links `compiler_minimal` without `php bin/compile.php` ([#3053](https://github.com/PurHur/php-compiler/issues/3053)). **M5 lib spine compile:** `BOOTSTRAP_NO_ZEND_FALLBACK=1 make bootstrap-selfhost-lib-spine-smoke` (default in link script) refuses host `php bin/compile.php` on the spine emit path ([#8716](https://github.com/PurHur/php-compiler/issues/8716)).
 
 **Project north star:** The **compiler fully compiles itself** — native AOT from `lib/` (no `vendor/` at cold boot), then compiles PHP and rebuilds the next compiler revision without Zend. **M2 spine:** **2643/2643** Phase A inventory (`php script/bootstrap-spine-count.php`; `check-selfhost-spine-coverage-sync.php`). **M5 daily gate:** `make north-star5-verify-fast` (~1–2 min) ✅; **`--strict`** (~1h) pre-merge only. Committed `prelinked/bootstrap-gen0/` sidecars + vendor **3/3** cold boot. **Hot loop:** VM driver execute probe ~**20ms**; full spine relink only with `BOOTSTRAP_VM_DRIVER_EXECUTE_PROBE_FULL_LINK=1` ([#2201](https://github.com/PurHur/php-compiler/issues/2201)). **Living tracker:** [#1492](https://github.com/PurHur/php-compiler/issues/1492) (was [#1056](https://github.com/PurHur/php-compiler/issues/1056)) · **re-root doc:** [self-host-target.md](self-host-target.md) · **generation ladder:** [bootstrap-generations.md](bootstrap-generations.md) · **M5 fast path:** [bootstrap-m5-fast-path.md](bootstrap-m5-fast-path.md) · public status: [development-status § North star](https://purhur.github.io/php-compiler/development-status.html#north-star-self-host). Parent tracking: [#78](https://github.com/PurHur/php-compiler/issues/78) (roadmap), [#212](https://github.com/PurHur/php-compiler/issues/212) (closed umbrella).
 
@@ -39,7 +39,7 @@
 | Self-host native link | `./script/bootstrap-selfhost-link.sh` | ✅ `build/selfhost` prints `compiler_minimal bundle OK` ([#557](https://github.com/PurHur/php-compiler/issues/557), [#913](https://github.com/PurHur/php-compiler/issues/913)) |
 | M2 lib spine smoke lint | `./script/bootstrap-selfhost-lib-spine-smoke-lint.sh` or `make bootstrap-selfhost-lib-spine-smoke-lint` | ✅ spine entry AOT lint — skip SourceBundler on `-l` ([#8391](https://github.com/PurHur/php-compiler/issues/8391)); uses `PHP_COMPILER_LLVM_MEMORY_LIMIT` |
 | M2 spine coverage drift | `php script/check-selfhost-spine-coverage-sync.php` | ✅ **2643** Phase A inventory files covered; `SELFHOST_SPINE_COVERAGE_SYNC_GATE=1` ([#1945](https://github.com/PurHur/php-compiler/issues/1945), [#2840](https://github.com/PurHur/php-compiler/issues/2840))
-| M2 lib spine smoke native run | `./script/bootstrap-selfhost-lib-spine-smoke-link.sh` or `BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke` | ✅ `build/selfhost-lib-spine-smoke` prints `compiler_lib_spine_smoke bundle OK` |
+| M2 lib spine smoke native run | `./script/bootstrap-selfhost-lib-spine-smoke-link.sh` or `BOOTSTRAP_LIB_SPINE_SMOKE=1 make bootstrap-selfhost-lib-spine-smoke` | ✅ `build/selfhost-lib-spine-smoke` prints `compiler_lib_spine_smoke bundle OK`; link script sets `BOOTSTRAP_NO_ZEND_FALLBACK=1` — no Zend gen-0 fallback ([#8716](https://github.com/PurHur/php-compiler/issues/8716)) |
 | M2 lib spine VM `-r` smoke | `./script/bootstrap-selfhost-lib-spine-vm-smoke.sh` or `BOOTSTRAP_LIB_SPINE_VM_SMOKE=1 make bootstrap-selfhost-lib-spine-vm-smoke` | ✅ same binary + `PHP_COMPILER_VM_SPINE_SMOKE=1` prints `vm-spine-ok` ([#1846](https://github.com/PurHur/php-compiler/issues/1846); `ci-local.sh` default `BOOTSTRAP_LIB_SPINE_VM_SMOKE_GATE=1` ([#1867](https://github.com/PurHur/php-compiler/issues/1867)); set `0` to skip) |
 | M2 VM driver execute | `./script/bootstrap-selfhost-vm-driver-execute-probe.sh` or `make bootstrap-selfhost-vm-driver-execute-probe` | ✅ spine binary + `PHP_COMPILER_VM_DRIVER_EXECUTE=1` → `vm driver ok` ([#2201](https://github.com/PurHur/php-compiler/issues/2201)); **~20ms** when binary present (no relink on stale SHA); `BOOTSTRAP_VM_DRIVER_EXECUTE_PROBE_FULL_LINK=1` for full rebuild; `ci-local.sh` default `BOOTSTRAP_VM_DRIVER_EXECUTE_GATE=1` ([#2227](https://github.com/PurHur/php-compiler/issues/2227)); opt-out `BOOTSTRAP_VM_DRIVER_EXECUTE_GATE=0` |
 | M3 HelloWorld self-host probe lint | `php bin/compile.php -l test/selfhost/compiler_helloworld_smoke/main.php` | ✅ `compiler_compile_smoke` spine + `helloworld_compile_smoke` driver (linkable) |

diff --git a/lib/JIT/Builtin/ObGzhandlerJitRuntime.php b/lib/JIT/Builtin/ObGzhandlerJitRuntime.php
@@ -265,12 +265,13 @@ private static function emitResolveEncoding(Context $context, LlvmFunction $fn):
         $context->builder->branch($doneBb);
         $context->builder->positionAtEnd($resolveBb);
         $resolved = self::emitReadAcceptEncoding($context, $fn);
+        $resolveDoneBb = $context->builder->getInsertBlock();
         $context->builder->store($resolved, $encPtr);
         $context->builder->branch($doneBb);
         $context->builder->positionAtEnd($doneBb);
         $phi = $context->builder->phi($i64, 'ogz_enc');
         $phi->addIncoming($cached, $cachedBb);
-        $phi->addIncoming($resolved, $resolveBb);
+        $phi->addIncoming($resolved, $resolveDoneBb);
 
         return $phi;
     }

diff --git a/script/bootstrap-resolve-compile-invoke.sh b/script/bootstrap-resolve-compile-invoke.sh
@@ -21,6 +21,7 @@
 #   BOOTSTRAP_GEN0_ZEND_ONLY=1  — always php bin/compile.php (requires php on PATH)
 #   BOOTSTRAP_ALLOW_GEN0_ZEND=0 — refuse Zend when no native driver (empty build/)
 #   BOOTSTRAP_M5_NO_ZEND=1       — refuse Zend fallback (implies BOOTSTRAP_NO_ZEND_FALLBACK=1)
+#   BOOTSTRAP_NO_ZEND_FALLBACK=1 — refuse Zend on spine/M5 compile paths (#8716)
 #   BOOTSTRAP_USE_INVENTORY_DRIVER=1 — inventory argv driver only (#2894)
 set -euo pipefail
 
@@ -366,8 +367,9 @@ bootstrap_ensure_inventory_argv_driver() {
         return 0
       fi
     fi
-    if [[ "${BOOTSTRAP_M5_NO_ZEND:-0}" == "1" ]]; then
-      echo "bootstrap-ensure-inventory-argv-driver: BOOTSTRAP_M5_NO_ZEND=1 — prelinked inventory driver failed smoke (#3053)" >&2
+    if [[ "${BOOTSTRAP_M5_NO_ZEND:-0}" == "1" || "${BOOTSTRAP_NO_ZEND_FALLBACK:-0}" == "1" ]]; then
+      rm -f "${out}" "${root}/build/.m3_bin_compile_aot_blob"
+      echo "bootstrap-ensure-inventory-argv-driver: BOOTSTRAP_NO_ZEND_FALLBACK=1 — prelinked inventory driver failed smoke (#8716, #3053)" >&2
       return 1
     fi
   fi

diff --git a/script/bootstrap-selfhost-lib-spine-smoke-link.sh b/script/bootstrap-selfhost-lib-spine-smoke-link.sh
@@ -129,11 +129,24 @@ if [[ "${BOOTSTRAP_LIB_SPINE_SMOKE_USE_COMPILE_INVOKE:-0}" != "1" ]]; then
     echo "bootstrap-selfhost-lib-spine-smoke-link: compile invoker=${SPINE_COMPILE_DRIVER} (no vendor/ tree)" >&2
   else
     # Emit-helper build/bin-compile-aot (gen-2 spine) must not masquerade as inventory argv driver (#3012).
-    if ! bootstrap_ensure_inventory_argv_driver "${INVENTORY_ARGV_DRIVER}"; then
-      echo "bootstrap-selfhost-lib-spine-smoke-link: failed to ensure inventory argv driver ${INVENTORY_ARGV_DRIVER}" >&2
-      exit 1
+    if bootstrap_ensure_inventory_argv_driver "${INVENTORY_ARGV_DRIVER}"; then
+      SPINE_COMPILE_DRIVER="${INVENTORY_ARGV_DRIVER}"
+    else
+      echo "bootstrap-selfhost-lib-spine-smoke-link: inventory argv driver unavailable (no Zend — #8716); resolving native driver" >&2
+      if ! bootstrap_resolve_compile_driver || [[ "${BOOTSTRAP_COMPILE_DRIVER_MODE:-}" != "native" ]]; then
+        echo "bootstrap-selfhost-lib-spine-smoke-link: building compiled argv driver (bootstrap-selfhost-driver-smoke) to avoid Zend fallback" >&2
+        if ! ./script/bootstrap-selfhost-driver-smoke.sh >/dev/null; then
+          echo "bootstrap-selfhost-lib-spine-smoke-link: failed to build compiled driver (see stderr above)" >&2
+          exit 1
+        fi
+        if ! bootstrap_resolve_compile_driver || [[ "${BOOTSTRAP_COMPILE_DRIVER_MODE:-}" != "native" ]]; then
+          echo "bootstrap-selfhost-lib-spine-smoke-link: compiled driver still missing after driver-smoke (would require Zend fallback)" >&2
+          exit 1
+        fi
+      fi
+      SPINE_COMPILE_DRIVER="${BOOTSTRAP_COMPILE_DRIVER}"
+      echo "bootstrap-selfhost-lib-spine-smoke-link: compile invoker=${SPINE_COMPILE_DRIVER} (inventory prelinked smoke failed — #8716)" >&2
     fi
-    SPINE_COMPILE_DRIVER="${INVENTORY_ARGV_DRIVER}"
   fi
 
   # Best-effort segfault breadcrumbs (written before invoking the native driver).

diff --git a/test/unit/BootstrapLibSpineVmSmokeTest.php b/test/unit/BootstrapLibSpineVmSmokeTest.php
@@ -55,15 +55,16 @@ public function testCompilePhpSkipsSourceBundlerForSpineLint(): void
         $this->assertStringContainsString('!$skipBundle', $compile);
     }
 
-    public function testLibSpineLinkScriptSeedsSidecarsAndGen0Fallback(): void
+    public function testLibSpineLinkScriptSeedsSidecarsAndRefusesZendFallback(): void
     {
         $script = (string) file_get_contents(self::$root.'/script/bootstrap-selfhost-lib-spine-smoke-link.sh');
         $this->assertStringContainsString('bootstrap-gen0-install-prelinked-driver.sh', $script);
         $this->assertStringContainsString('ci_ensure_vendor_patches', $script);
         $this->assertStringContainsString('bootstrap_ensure_m3_compiler_lib_sidecar', $script);
-        $this->assertStringContainsString('PHP_COMPILER_M3_SIDECAR_HOST=1', $script);
+        $this->assertStringContainsString('export BOOTSTRAP_NO_ZEND_FALLBACK=1', $script);
+        $this->assertStringContainsString('inventory argv driver unavailable (no Zend — #8716)', $script);
         $this->assertStringContainsString('BOOTSTRAP_LIB_SPINE_SMOKE_GEN0_FALLBACK', $script);
-        $this->assertStringContainsString('gen-0 Zend fallback', $script);
+        $this->assertStringContainsString('BOOTSTRAP_NO_ZEND_FALLBACK:-0}" != "1"', $script);
     }
 
     public function testSpineEntryBundlesBinVmPhp(): void

diff --git a/test/unit/BootstrapSelfhostLinkTest.php b/test/unit/BootstrapSelfhostLinkTest.php
@@ -112,11 +112,16 @@ public function testLinkScriptUsesCompiledDriverResolver(): void
         $this->assertStringContainsString('falling back to Zend gen-0', $body);
         $this->assertStringContainsString('BOOTSTRAP_M5_NO_ZEND', $body);
         $this->assertStringContainsString(
-            'BOOTSTRAP_M5_NO_ZEND=1 — prelinked inventory driver failed smoke',
+            'BOOTSTRAP_NO_ZEND_FALLBACK=1 — prelinked inventory driver failed smoke',
             $body,
-            'inventory argv driver refuses Zend rebuild under M5 no-Zend (#3053)'
+            'inventory argv driver refuses Zend rebuild when no-Zend fallback (#8716, #3053)'
         );
 
+        $spineLink = (string) file_get_contents(self::$root.'/script/bootstrap-selfhost-lib-spine-smoke-link.sh');
+        $this->assertStringContainsString('export BOOTSTRAP_NO_ZEND_FALLBACK=1', $spineLink);
+        $this->assertStringContainsString('inventory argv driver unavailable (no Zend — #8716)', $spineLink);
+        $this->assertStringContainsString('BOOTSTRAP_NO_ZEND_FALLBACK:-0}" != "1"', $spineLink);
+
         $coldBoot = self::$root.'/script/bootstrap-selfhost-cold-boot-probe.sh';
         $this->assertFileExists($coldBoot);
         $this->assertStringContainsString('BOOTSTRAP_M5_NO_ZEND=1', (string) file_get_contents($coldBoot));