fix(*) ensure fake requests filter chains are freed

Such as fake request passed to the FFI via the init_worker_by_lua fake
request.

src/common/lua/ngx_wasm_lua_ffi.c

@@ -191,7 +191,9 @@ ngx_http_wasm_ffi_set_property(ngx_http_request_t *r,
         return NGX_ERROR;
     }
 
-    pwctx = ngx_http_proxy_wasm.get_context(rctx);
+    pwctx = ngx_proxy_wasm_ctx(NULL, 0,
+                               NGX_PROXY_WASM_ISOLATION_STREAM,
+                               &ngx_http_proxy_wasm, rctx);
     if (pwctx == NULL) {
         return NGX_ERROR;
     }
@@ -208,14 +210,16 @@ ngx_http_wasm_ffi_get_property(ngx_http_request_t *r,
     ngx_proxy_wasm_ctx_t     *pwctx;
 
     if (ngx_http_wasm_rctx(r, &rctx) != NGX_OK) {
-        /*
+        /**
          * TODO: return code signifying "no plan attached to request" and co.
          * return associated constant as err/code from Lua lib
          */
         return NGX_ERROR;
     }
 
-    pwctx = ngx_http_proxy_wasm.get_context(rctx);
+    pwctx = ngx_proxy_wasm_ctx(NULL, 0,
+                               NGX_PROXY_WASM_ISOLATION_STREAM,
+                               &ngx_http_proxy_wasm, rctx);
     if (pwctx == NULL) {
         return NGX_ERROR;
     }

src/http/proxy_wasm/ngx_http_proxy_wasm.c

@@ -346,13 +346,23 @@ ngx_http_proxy_wasm_ecode(ngx_proxy_wasm_err_e ecode)
 }
 
 
+static void
+ngx_http_proxy_wasm_ctx_cleanup_handler(void *data)
+{
+    ngx_proxy_wasm_ctx_t  *pwctx = data;
+
+    ngx_proxy_wasm_ctx_destroy(pwctx);
+}
+
+
 static ngx_proxy_wasm_ctx_t *
 ngx_http_proxy_wasm_ctx(void *data)
 {
     ngx_proxy_wasm_ctx_t      *pwctx;
     ngx_http_wasm_req_ctx_t   *rctx = data;
     ngx_http_request_t        *r = rctx->r;
     ngx_http_wasm_loc_conf_t  *loc;
+    ngx_pool_cleanup_t        *cln;
 
     loc = ngx_http_get_module_loc_conf(r, ngx_http_wasm_module);
 
@@ -374,6 +384,16 @@ ngx_http_proxy_wasm_ctx(void *data)
 
         /* for on_request_body retrieval */
         rctx->data = pwctx;
+
+        if (rctx->fake_request) {
+            cln = ngx_pool_cleanup_add(pwctx->parent_pool, 0);
+            if (cln == NULL) {
+                return NULL;
+            }
+
+            cln->handler = ngx_http_proxy_wasm_ctx_cleanup_handler;
+            cln->data = pwctx;
+        }
     }
 
     return pwctx;