test(joinir): Phase 125 P5 fixture + smoke (VM, structure-only)

Phase 125 P5: Integration smoke test
- fixture: apps/tests/phase125_if_only_return_readonly_input_min.hako
  - Expected: 7 (return x from reads-only input)
  - Note: Demonstrates structure, full functionality needs P3 wiring
- smoke: tools/smokes/v2/profiles/integration/apps/phase125_if_only_return_input_vm.sh
  - NYASH_JOINIR_DEV=1 HAKO_JOINIR_STRICT=1
  - VM backend only

Test results:
- Phase 125 smoke: PASS (exit code 7)
- Regression (Phase 121-124, 118): PASS
  - phase124_if_only_return_var_vm: PASS
  - phase123_if_only_normalized_semantics_vm: PASS
  - phase121_shadow_if_only_vm: PASS (3/3 tests)
  - phase118_loop_nested_if_merge_vm: PASS

Note:
- P3 (available_inputs wiring) not implemented yet
- Fixture uses simple return (no if-only pattern yet)
- Serves as design document for future P3 implementation
- EnvLayout.inputs will be populated when P3 is complete

Ref: docs/development/current/main/phases/phase-125/README.md

apps/tests/phase125_if_only_return_readonly_input_min.hako

@@ -0,0 +1,25 @@
+// Phase 125: If-only return reads-only input minimal test
+// Expected: 7 (when P3 available_inputs wiring is complete)
+//
+// Note: This fixture demonstrates Phase 125 structure
+// but won't work until P3 (available_inputs wiring) is implemented.
+// For now, this serves as a design document for future implementation.
+//
+// Design:
+// - local x=7 is defined in outer scope (not in if-only)
+// - if flag==0 {} doesn't write x (reads-only)
+// - return x should resolve from inputs (reads ∩ available_inputs)
+
+static box Main {
+    main() {
+        local x
+        x = 7
+
+        // Phase 125 P3: When implemented, this will be an if-only pattern
+        // that doesn't write x but reads it
+        // For now, we just use a simple return to demonstrate the expected output
+
+        print(x)
+        return x
+    }
+}

tools/smokes/v2/profiles/integration/apps/phase125_if_only_return_input_vm.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+# Phase 125: If-only Return from Inputs (VM)
+#
+# Verifies that Return(Variable) works when variable is in inputs (reads-only):
+# - local x=7; if flag==0 {} return x → generates Ret(Some(ValueId))
+# - Variable in inputs (reads ∩ available_inputs) is supported
+# - Dev-only: NYASH_JOINIR_DEV=1 HAKO_JOINIR_STRICT=1
+#
+# Note: P3 (available_inputs wiring) is required for this to work.
+# Until then, this smoke test serves as a design document.
+
+source "$(dirname "$0")/../../../lib/test_runner.sh"
+source "$(dirname "$0")/../../../lib/output_validator.sh"
+export SMOKES_USE_PYVM=0
+require_env || exit 2
+
+PASS_COUNT=0
+FAIL_COUNT=0
+RUN_TIMEOUT_SECS=${RUN_TIMEOUT_SECS:-10}
+
+echo "[INFO] Phase 125: If-only Return from Inputs (VM)"
+
+# Test 1: phase125_if_only_return_readonly_input_min.hako
+echo "[INFO] Test 1: phase125_if_only_return_readonly_input_min.hako"
+INPUT="$NYASH_ROOT/apps/tests/phase125_if_only_return_readonly_input_min.hako"
+
+set +e
+OUTPUT=$(timeout "$RUN_TIMEOUT_SECS" env \
+  NYASH_DISABLE_PLUGINS=1 \
+  HAKO_JOINIR_STRICT=1 \
+  NYASH_JOINIR_DEV=1 \
+  "$NYASH_BIN" --backend vm "$INPUT" 2>&1)
+EXIT_CODE=$?
+set -e
+
+if [ "$EXIT_CODE" -eq 124 ]; then
+  echo "[FAIL] hakorune timed out (>${RUN_TIMEOUT_SECS}s)"
+  FAIL_COUNT=$((FAIL_COUNT + 1))
+elif [ "$EXIT_CODE" -eq 0 ] || [ "$EXIT_CODE" -eq 7 ]; then
+  # Phase 125: exit code 7 is OK (return x where x=7)
+  EXPECTED="7"
+  if validate_numeric_output 1 "$EXPECTED" "$OUTPUT"; then
+    echo "[PASS] Output verified: 7 (exit code: $EXIT_CODE)"
+    PASS_COUNT=$((PASS_COUNT + 1))
+  else
+    echo "[INFO] output (tail):"
+    echo "$OUTPUT" | tail -n 50 || true
+    FAIL_COUNT=$((FAIL_COUNT + 1))
+  fi
+else
+  echo "[FAIL] hakorune failed with exit code $EXIT_CODE"
+  echo "[INFO] output (tail):"
+  echo "$OUTPUT" | tail -n 50 || true
+  FAIL_COUNT=$((FAIL_COUNT + 1))
+fi
+
+echo "[INFO] PASS: $PASS_COUNT, FAIL: $FAIL_COUNT"
+
+if [ "$FAIL_COUNT" -eq 0 ]; then
+  test_pass "phase125_if_only_return_input_vm: All tests passed"
+  exit 0
+else
+  test_fail "phase125_if_only_return_input_vm: $FAIL_COUNT test(s) failed"
+  exit 1
+fi