[tarantool-patches] Re: [PATCH] box: fix bug with module_reload() without box.cfg{}

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Hi! Thanks for the patch! See 5 comments below.

On 05/02/2019 01:17, Roman Khabibov wrote:
> Fix bug with segfault when use module_reload() before box.cfg{}.

1. Instead of duplicating commit title, it is usually
better to describe here a reason why the bug existed.

> 
> Closes #3770
> 
> Branch: https://github.com/tarantool/tarantool/tree/romanhabibov/gh-3770-module-reload
> Issue: https://github.com/tarantool/tarantool/issues/3770

2. Please, put branch and issue links after '---'.

> ---

Here.

>   src/box/func.c                | 3 +++
>   test/box/func_reload.result   | 9 +++++++++
>   test/box/func_reload.test.lua | 5 +++++
>   3 files changed, 17 insertions(+)
> 
> diff --git a/src/box/func.c b/src/box/func.c
> index a817851fd..ee6dd55dc 100644
> --- a/src/box/func.c
> +++ b/src/box/func.c
> @@ -301,6 +301,9 @@ module_sym(struct module *module, const char *name)
>   int
>   module_reload(const char *package, const char *package_end, struct module **module)
>   {
> +	if (!modules)
> +		return -1;

3. As you know, we use == NULL instead of ! when dealing with pointers.

4. Instead of checking for modules != NULL in each public func.h function,
it is better to move module_init() call from box_cfg_xc() to box_init(). Then
main() will create modules hash.

> +
>   	struct module *old_module = module_cache_find(package, package_end);
>   	if (old_module == NULL) {
>   		/* Module wasn't loaded - do nothing. */
> diff --git a/test/box/func_reload.test.lua b/test/box/func_reload.test.lua
> index 8906898ec..00fe8cf48 100644
> --- a/test/box/func_reload.test.lua
> +++ b/test/box/func_reload.test.lua
> @@ -1,3 +1,8 @@
> +-- gh-3770 Check no segfault with module_reload() without box.cfg{}.
> +
> +box.internal.module_reload('')
> +box.internal.module_reload('xxx')

5. Not-tap tests are always run with already called box.cfg(),
so these lines here will work regardless of your patch. Please,
move it to a tap test, in app-tap directory. Now I do not see
there any existing and suitable file for this test, so you
should create a new one. For example, app-tap/func.test.lua.

> +
>   fio  = require('fio')
>   net = require('net.box')
>   fiber = require('fiber')
> -- 
> 2.17.1
> 
>