SSI: prevent fallback from emitting twice

src/http/modules/ngx_http_ssi_filter_module.c

@@ -2232,12 +2232,30 @@ ngx_http_ssi_include(ngx_http_request_t *r, ngx_http_ssi_ctx_t *ctx,
 static ngx_int_t
 ngx_http_ssi_stub_output(ngx_http_request_t *r, void *data, ngx_int_t rc)
 {
-    ngx_chain_t  *out;
+    ngx_chain_t        *out;
+    ngx_http_ssi_ctx_t *ctx;
 
     if (rc == NGX_ERROR || r->connection->error || r->request_output) {
         return rc;
     }
 
+    ctx = ngx_http_get_module_ctx(r, ngx_http_ssi_filter_module);
+
+    if (ctx && ctx->stub_output_done) {
+        return NGX_OK;
+    }
+
+    if (ctx == NULL) {
+        ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_ssi_ctx_t));
+        if (ctx == NULL) {
+            return NGX_ERROR;
+        }
+
+        ngx_http_set_ctx(r, ctx, ngx_http_ssi_filter_module);
+    }
+
+    ctx->stub_output_done = 1;
+
     ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                    "ssi stub output: \"%V?%V\"", &r->uri, &r->args);
 

src/http/modules/ngx_http_ssi_filter_module.h

@@ -82,6 +82,8 @@ typedef struct {
     void                     *value_buf;
     ngx_str_t                 timefmt;
     ngx_str_t                 errmsg;
+
+    ngx_uint_t                stub_output_done;
 } ngx_http_ssi_ctx_t;
 
 

src/http/ngx_http_request.c

@@ -2526,7 +2526,6 @@ ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
 
     if (r != r->main && r->post_subrequest) {
         rc = r->post_subrequest->handler(r, r->post_subrequest->data, rc);
-        r->post_subrequest = NULL;
     }
 
     if (rc == NGX_ERROR