Re: [Tarantool-patches] [PATCH v2 06/10] box: introduce stacked diagnostic area

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

Two more comments.

> diff --git a/test/box/error.test.lua b/test/box/error.test.lua
> index a0b7d3e78..1fdd6ed98 100644
> --- a/test/box/error.test.lua
> +++ b/test/box/error.test.lua
> @@ -108,4 +108,109 @@ box.error.new(err)
> +
>  space:drop()

1. You probably need to keep this 'space:drop()' after
the test related to it.

2. Also I did some double checking if there are no leaks. And came
up with that test:

====================
diff --git a/extra/exports b/extra/exports
index 9323996c1..f581026fb 100644
--- a/extra/exports
+++ b/extra/exports
@@ -43,6 +43,7 @@ tnt_iconv_close
 tnt_iconv
 exception_get_string
 exception_get_int
+get_error_count
 
 tarantool_lua_ibuf
 uuid_nil
diff --git a/src/lib/core/diag.c b/src/lib/core/diag.c
index 57da5da44..f5d3c8a18 100644
--- a/src/lib/core/diag.c
+++ b/src/lib/core/diag.c
@@ -31,6 +31,14 @@
 #include "diag.h"
 #include "fiber.h"
 
+int diag_error_count = 0;
+
+int
+get_error_count(void)
+{
+	return __atomic_load_n(&diag_error_count, __ATOMIC_SEQ_CST);
+}
+
 /* Must be set by the library user */
 struct error_factory *error_factory = NULL;
 
@@ -76,6 +84,7 @@ error_create(struct error *e,
 	     error_f destroy, error_f raise, error_f log,
 	     const struct type_info *type, const char *file, unsigned line)
 {
+	__atomic_add_fetch(&diag_error_count, 1, __ATOMIC_SEQ_CST);
 	e->destroy = destroy;
 	e->raise = raise;
 	e->log = log;
@@ -92,6 +101,7 @@ error_create(struct error *e,
 	e->errmsg[0] = '\0';
 	e->cause = NULL;
 	e->effect = NULL;
+
 }
 
 struct diag *
diff --git a/src/lib/core/diag.h b/src/lib/core/diag.h
index 665f492fa..bd4ddcf3e 100644
--- a/src/lib/core/diag.h
+++ b/src/lib/core/diag.h
@@ -47,11 +47,16 @@ enum {
 	DIAG_FILENAME_MAX = 256
 };
 
+extern int diag_error_count;
+
 struct type_info;
 struct error;
 
 typedef void (*error_f)(struct error *e);
 
+int
+get_error_count(void);
+
 /**
  * Error diagnostics needs to be equally usable in C and C++
  * code. This is why there is a common infrastructure for errors.
@@ -136,6 +141,7 @@ error_unref(struct error *e)
 		if (cause == NULL)
 			return;
 		to_delete = cause;
+		__atomic_add_fetch(&diag_error_count, -1, __ATOMIC_SEQ_CST);
 	}
 }
 
diff --git a/test/box/error.test.lua b/test/box/error.test.lua
index 1fdd6ed98..8f884c372 100644
--- a/test/box/error.test.lua
+++ b/test/box/error.test.lua
@@ -78,6 +78,25 @@ t;
 
 test_run:cmd("setopt delimiter ''");
 
+ffi = require('ffi')
+
+ffi.cdef[[						\
+	int 						\
+	get_error_count(void); 				\
+]]
+
+e1 = nil
+e2 = nil
+e3 = nil
+e4 = nil
+e5 = nil
+err = nil
+box.error.clear()
+collectgarbage('collect')
+collectgarbage('collect')
+
+errcount = ffi.C.get_error_count()
+
 -- gh-4778: don't add created via box.error.new() errors to
 -- Tarantool's diagnostic area.
 --
@@ -213,4 +232,20 @@ box.error.set(e1)
 box.error.clear()
 assert(e1.prev == e2)
 
+e1 = nil
+e2 = nil
+e3 = nil
+e4 = nil
+e5 = nil
+err = nil
+box.error.clear()
+
+collectgarbage('collect')
+collectgarbage('collect')
+
+errcount2 = ffi.C.get_error_count()
+
+errcount
+errcount2
+
 space:drop()
====================

errcount is 13, errcount2 is 17. Something is probably wrong.
I thought these were errors created before line

    gh-4778: don't add created via box.error.new() errors to

But the difference still should be 0. Because I nullified and
cleared all variables you use before and after the test. I tried
commenting out all the code before this line, and still get a
not 0 difference. I ask you to check why some errors are not
deleted.