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From: Cyrill Gorcunov via Tarantool-patches <tarantool-patches@dev.tarantool.org>
To: tml <tarantool-patches@dev.tarantool.org>
Cc: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Subject: [Tarantool-patches] [PATCH v14 05/12] module_cache: add comment about weird resolving
Date: Wed,  3 Feb 2021 01:12:00 +0300	[thread overview]
Message-ID: <20210202221207.383101-6-gorcunov@gmail.com> (raw)
In-Reply-To: <20210202221207.383101-1-gorcunov@gmail.com>

The module management is not obvious when reading
the code, mostly because of weird design in first
place which we can't change without breaking
backward compatibility.

Add a note about this into code itself otherwise
it is hard to understand why it works the way it
does.

Part-of #4642

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
 src/box/module_cache.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/box/module_cache.c b/src/box/module_cache.c
index 9e5670c03..60af290ae 100644
--- a/src/box/module_cache.c
+++ b/src/box/module_cache.c
@@ -418,6 +418,18 @@ int
 module_sym_call(struct module_sym *mod_sym, struct port *args,
 		struct port *ret)
 {
+	/*
+	 * The functions created with `box.schema.func`
+	 * help are not resolved immediately. Instead
+	 * they are deferred until first call. And when
+	 * call happens the we try to load a module and
+	 * resolve a symbol (which of course can fail if
+	 * there is no such module at all).
+	 *
+	 * While this is very weird (and frankly speaking
+	 * very bad design) we can't change it for backward
+	 * compatibility sake!
+	 */
 	if (mod_sym->addr == NULL) {
 		if (module_sym_load(mod_sym) != 0)
 			return -1;
-- 
2.29.2


  parent reply	other threads:[~2021-02-02 22:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 22:11 [Tarantool-patches] [PATCH v14 00/12] box: implement cmod Lua module Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:11 ` [Tarantool-patches] [PATCH v14 01/12] box/func: factor out c function entry structure Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:11 ` [Tarantool-patches] [PATCH v14 02/12] module_cache: move module handling into own subsystem Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:11 ` [Tarantool-patches] [PATCH v14 03/12] module_cache: direct update a cache value on reload Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:11 ` [Tarantool-patches] [PATCH v14 04/12] module_cache: rename calls to ref in module structure Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` Cyrill Gorcunov via Tarantool-patches [this message]
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 06/12] module_cache: module_reload - drop redundant parameter Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 07/12] module_cache: use references as a main usage counter Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 08/12] module_cache: make module to carry hash it belongs to Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 09/12] module_cache: use own hash for box.schema.func requests Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 10/12] module_cache: provide module_load/unload calls Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 11/12] box/cmod: implement cmod Lua module Cyrill Gorcunov via Tarantool-patches
2021-02-02 22:12 ` [Tarantool-patches] [PATCH v14 12/12] test: box/cfunc -- add cmod test Cyrill Gorcunov via Tarantool-patches

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