[Tarantool-patches] [PATCH 2/7] box/error: introduce box.error.set() method

[Nikita Pettik]

box.error.set(err) sets err to instance's diagnostics area. Argument err
is supposed to be instance of error object. This method is required
since we are going to avoid adding created via box.error.new() errors to
Tarantool's diagnostic area.

Needed for #1148
Part of #4778
---
 src/box/lua/error.cc   | 15 +++++++++++++++
 src/lua/error.c        |  2 +-
 src/lua/error.h        |  3 +++
 test/box/misc.result   | 34 ++++++++++++++++++++++++++++++++++
 test/box/misc.test.lua | 14 ++++++++++++++
 5 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/box/lua/error.cc b/src/box/lua/error.cc
index fc53a40f4..7311cb2ce 100644
--- a/src/box/lua/error.cc
+++ b/src/box/lua/error.cc
@@ -154,6 +154,17 @@ luaT_error_clear(lua_State *L)
 	return 0;
 }
 
+static int
+luaT_error_set(lua_State *L)
+{
+	if (lua_gettop(L) == 0)
+		return luaL_error(L, "Usage: box.error.set(error)");
+	struct error *e = luaL_checkerror(L, 1);
+	assert(e != NULL);
+	diag_set_error(&fiber()->diag, e);
+	return 0;
+}
+
 static int
 lbox_errinj_set(struct lua_State *L)
 {
@@ -268,6 +279,10 @@ box_lua_error_init(struct lua_State *L) {
 			lua_pushcfunction(L, luaT_error_new);
 			lua_setfield(L, -2, "new");
 		}
+		{
+			lua_pushcfunction(L, luaT_error_set);
+			lua_setfield(L, -2, "set");
+		}
 		lua_setfield(L, -2, "__index");
 	}
 	lua_setmetatable(L, -2);
diff --git a/src/lua/error.c b/src/lua/error.c
index d82e78dc4..18a990a88 100644
--- a/src/lua/error.c
+++ b/src/lua/error.c
@@ -53,7 +53,7 @@ luaL_iserror(struct lua_State *L, int narg)
 	return e;
 }
 
-static struct error *
+struct error *
 luaL_checkerror(struct lua_State *L, int narg)
 {
 	struct error *error = luaL_iserror(L, narg);
diff --git a/src/lua/error.h b/src/lua/error.h
index 64fa5eba3..16cdaf7fe 100644
--- a/src/lua/error.h
+++ b/src/lua/error.h
@@ -65,6 +65,9 @@ luaT_pusherror(struct lua_State *L, struct error *e);
 struct error *
 luaL_iserror(struct lua_State *L, int narg);
 
+struct error *
+luaL_checkerror(struct lua_State *L, int narg);
+
 void
 tarantool_lua_error_init(struct lua_State *L);
 
diff --git a/test/box/misc.result b/test/box/misc.result
index 5ac5e0f26..48c00aadc 100644
--- a/test/box/misc.result
+++ b/test/box/misc.result
@@ -290,6 +290,40 @@ type(err.errno)
 ---
 - nil
 ...
+-- gh-4778: don't add created via box.error.new() errors to
+-- Tarantool's diagnostic area.
+--
+err = box.error.new({code = 111, reason = "cause"})
+---
+...
+assert(box.error.last() ~= err)
+---
+- error: assertion failed!
+...
+box.error.set(err)
+---
+...
+assert(box.error.last() == err)
+---
+- true
+...
+-- Consider wrong or tricky inputs to box.error.set()
+--
+box.error.set(1)
+---
+- error: 'Invalid argument #1 (error expected, got number)'
+...
+box.error.set(nil)
+---
+- error: 'Invalid argument #1 (error expected, got nil)'
+...
+box.error.set(box.error.last())
+---
+...
+assert(box.error.last() == err)
+---
+- true
+...
 ----------------
 -- # box.stat
 ----------------
diff --git a/test/box/misc.test.lua b/test/box/misc.test.lua
index e1c2f990f..cb7b775fc 100644
--- a/test/box/misc.test.lua
+++ b/test/box/misc.test.lua
@@ -91,6 +91,20 @@ type(err.errno)
 err = box.error.new(box.error.PROC_LUA, "errno")
 type(err.errno)
 
+-- gh-4778: don't add created via box.error.new() errors to
+-- Tarantool's diagnostic area.
+--
+err = box.error.new({code = 111, reason = "cause"})
+assert(box.error.last() ~= err)
+box.error.set(err)
+assert(box.error.last() == err)
+-- Consider wrong or tricky inputs to box.error.set()
+--
+box.error.set(1)
+box.error.set(nil)
+box.error.set(box.error.last())
+assert(box.error.last() == err)
+
 ----------------
 -- # box.stat
 ----------------
-- 
2.15.1