[njs] Modules: fixed promise events handling.

[Alexander Borisov]

details:   https://hg.nginx.org/njs/rev/fac7e5dc8009
branches:  
changeset: 1575:fac7e5dc8009
user:      Alexander Borisov <alexander.borisov at nginx.com>
date:      Thu Nov 26 21:43:17 2020 +0300
description:
Modules: fixed promise events handling.

Previously, promise chain might not be invoked at all in some cases.
Specifically, this happened in HTTP module if promise chain did not start
with a r.subrequest() invocation.

The fix is to always process all pending promise events after the main module
function.

This closes #359 issue on GitHub.

diffstat:

 nginx/ngx_js.c |  6 +-----
 src/njs_vm.c   |  2 +-
 2 files changed, 2 insertions(+), 6 deletions(-)

diffs (28 lines):

diff -r a141a29417dc -r fac7e5dc8009 nginx/ngx_js.c
--- a/nginx/ngx_js.c	Thu Nov 26 11:36:03 2020 +0000
+++ b/nginx/ngx_js.c	Thu Nov 26 21:43:17 2020 +0300
@@ -79,11 +79,7 @@ ngx_js_call(njs_vm_t *vm, ngx_str_t *fna
         return NGX_ERROR;
     }
 
-    if (njs_vm_pending(vm)) {
-        return NGX_AGAIN;
-    }
-
-    return NGX_OK;
+    return njs_vm_run(vm);
 }
 
 
diff -r a141a29417dc -r fac7e5dc8009 src/njs_vm.c
--- a/src/njs_vm.c	Thu Nov 26 11:36:03 2020 +0000
+++ b/src/njs_vm.c	Thu Nov 26 21:43:17 2020 +0300
@@ -578,7 +578,7 @@ njs_vm_handle_events(njs_vm_t *vm)
 
     } while (!njs_queue_is_empty(promise_events));
 
-    return njs_posted_events(vm) ? NJS_AGAIN : NJS_OK;
+    return njs_vm_pending(vm) ? NJS_AGAIN : NJS_OK;
 }