[Tarantool-patches] [PATCH V3 3/7] error: send custom type in IProto

[Leonid Vasiliev]

Error custom type features were added to the public
Lua API in the previous commits. This one makes the new attribute
being sent in IProto.

Co-authored-by: Vladislav Shpilevoy<v.shpilevoy at tarantool.org>

Needed for #4398

@TarantoolBot document
Title: New error object attributes in IProto

Error objects in IProto already have 2 fields:
`IPROTO_ERROR_CODE = 0x01` and `IPROTO_ERROR_MESSAGE = 0x02`.

Now added:

`IPROTO_ERROR_CUSTOM_TYPE = 0x03`.

It's optional, have MP_STR type, and speak for themselves.
Custom error type is error object attribute.
This is what a user specifies in
`box.error.new({type = <custom_type>})` or
`box.error.new(<custom_type>)`.
---
 extra/exports              |  1 +
 src/box/iproto_constants.h |  1 +
 src/box/lua/net_box.lua    | 14 +++++++++++---
 src/box/xrow.c             |  9 ++++++++-
 test/box/error.result      | 40 ++++++++++++++++++++++++++++++++++++++++
 test/box/error.test.lua    | 17 +++++++++++++++++
 6 files changed, 78 insertions(+), 4 deletions(-)

diff --git a/extra/exports b/extra/exports
index 9467398..b01b437 100644
--- a/extra/exports
+++ b/extra/exports
@@ -242,6 +242,7 @@ box_error_last
 box_error_clear
 box_error_set
 error_set_prev
+error_set_traceback
 box_latch_new
 box_latch_delete
 box_latch_lock
diff --git a/src/box/iproto_constants.h b/src/box/iproto_constants.h
index 7ed8296..1fca97b 100644
--- a/src/box/iproto_constants.h
+++ b/src/box/iproto_constants.h
@@ -154,6 +154,7 @@ enum iproto_ballot_key {
 enum iproto_error_key {
 	IPROTO_ERROR_CODE = 0x01,
 	IPROTO_ERROR_MESSAGE = 0x02,
+	IPROTO_ERROR_CUSTOM_TYPE = 0x03,
 };
 
 #define bit(c) (1ULL<<IPROTO_##c)
diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
index 07fa54c..95f9cf8 100644
--- a/src/box/lua/net_box.lua
+++ b/src/box/lua/net_box.lua
@@ -10,6 +10,11 @@ local urilib   = require('uri')
 local internal = require('net.box.lib')
 local trigger  = require('internal.trigger')
 
+ffi.cdef[[
+void
+error_set_traceback(struct error *e, const char *traceback);
+]]
+
 local band              = bit.band
 local max               = math.max
 local fiber_clock       = fiber.clock
@@ -47,6 +52,7 @@ local IPROTO_ERROR_KEY     = 0x31
 local IPROTO_ERROR_STACK   = 0x52
 local IPROTO_ERROR_CODE    = 0x01
 local IPROTO_ERROR_MESSAGE = 0x02
+local IPROTO_ERROR_CUSTOM_TYPE = 0x03
 local IPROTO_GREETING_SIZE = 128
 local IPROTO_CHUNK_KEY     = 128
 local IPROTO_OK_KEY        = 0
@@ -285,9 +291,11 @@ local function create_transport(host, port, user, password, callback,
                 local prev = nil
                 for i = #self.response, 1, -1 do
                     local error = self.response[i]
-                    local code = error[IPROTO_ERROR_CODE]
-                    local msg = error[IPROTO_ERROR_MESSAGE]
-                    local new_err = box.error.new({code = code, reason = msg})
+                    local new_err = box.error.new({
+                        type = error[IPROTO_ERROR_CUSTOM_TYPE],
+                        code = error[IPROTO_ERROR_CODE],
+                        reason = error[IPROTO_ERROR_MESSAGE],
+                    })
                     new_err:set_prev(prev)
                     prev = new_err
                 end
diff --git a/src/box/xrow.c b/src/box/xrow.c
index 5494b41..a717da6 100644
--- a/src/box/xrow.c
+++ b/src/box/xrow.c
@@ -494,11 +494,18 @@ mpstream_iproto_encode_error(struct mpstream *stream, const struct error *error)
 	mpstream_encode_uint(stream, IPROTO_ERROR_STACK);
 	mpstream_encode_array(stream, err_cnt);
 	for (const struct error *it = error; it != NULL; it = it->cause) {
-		mpstream_encode_map(stream, 2);
+		uint32_t map_size = 2;
+		const char *custom_type = box_error_custom_type(it);
+		map_size += (custom_type != NULL);
+		mpstream_encode_map(stream, map_size);
 		mpstream_encode_uint(stream, IPROTO_ERROR_CODE);
 		mpstream_encode_uint(stream, box_error_code(it));
 		mpstream_encode_uint(stream, IPROTO_ERROR_MESSAGE);
 		mpstream_encode_str(stream, it->errmsg);
+		if (custom_type != NULL) {
+			mpstream_encode_uint(stream, IPROTO_ERROR_CUSTOM_TYPE);
+			mpstream_encode_str(stream, custom_type);
+		}
 	}
 }
 
diff --git a/test/box/error.result b/test/box/error.result
index b717a4f..ced227f 100644
--- a/test/box/error.result
+++ b/test/box/error.result
@@ -949,3 +949,43 @@ e = box.error.new({type = string.rep('a', 128)})
  | ---
  | - 63
  | ...
+
+--
+-- Check how custom error type are passed through
+-- IProto.
+--
+netbox = require('net.box')
+ | ---
+ | ...
+box.schema.user.grant('guest', 'super')
+ | ---
+ | ...
+c = netbox.connect(box.cfg.listen)
+ | ---
+ | ...
+_, e = pcall(c.call, c, 'box.error', {                                          \
+    {code = 123, type = 'TestType', reason = 'Test reason'}   \
+})
+ | ---
+ | ...
+e = e:unpack()
+ | ---
+ | ...
+e.trace = nil
+ | ---
+ | ...
+e
+ | ---
+ | - code: 123
+ |   type: TestType
+ |   custom_type: TestType
+ |   message: Test reason
+ |   base_type: CustomError
+ | ...
+
+c:close()
+ | ---
+ | ...
+box.schema.user.revoke('guest', 'super')
+ | ---
+ | ...
diff --git a/test/box/error.test.lua b/test/box/error.test.lua
index fe40518..b71ab52 100644
--- a/test/box/error.test.lua
+++ b/test/box/error.test.lua
@@ -278,3 +278,20 @@ e:unpack()
 -- Try too long type name.
 e = box.error.new({type = string.rep('a', 128)})
 #e.type
+
+--
+-- Check how custom error type are passed through
+-- IProto.
+--
+netbox = require('net.box')
+box.schema.user.grant('guest', 'super')
+c = netbox.connect(box.cfg.listen)
+_, e = pcall(c.call, c, 'box.error', {                                          \
+    {code = 123, type = 'TestType', reason = 'Test reason'}   \
+})
+e = e:unpack()
+e.trace = nil
+e
+
+c:close()
+box.schema.user.revoke('guest', 'super')
-- 
2.7.4