box: user.grant error should be versatile

Error message on granted privileges was not flexible and
did not distinguish between universal or any other privileges
leaving either 'nil' or simply '' at the end.

Closes #714

src/box/errcode.h

@@ -141,7 +141,7 @@ struct errcode_record {
 	/* 86 */_(ER_SESSION_CLOSED,		"Session is closed") \
 	/* 87 */_(ER_ROLE_LOOP,			"Granting role '%s' to role '%s' would create a loop") \
 	/* 88 */_(ER_GRANT,			"Incorrect grant arguments: %s") \
-	/* 89 */_(ER_PRIV_GRANTED,		"User '%s' already has %s access on %s '%s'") \
+	/* 89 */_(ER_PRIV_GRANTED,		"User '%s' already has %s access on %s%s") \
 	/* 90 */_(ER_ROLE_GRANTED,		"User '%s' already has role '%s'") \
 	/* 91 */_(ER_PRIV_NOT_GRANTED,		"User '%s' does not have %s access on %s '%s'") \
 	/* 92 */_(ER_ROLE_NOT_GRANTED,		"User '%s' does not have role '%s'") \

src/box/lua/schema.lua

@@ -2408,6 +2408,9 @@ local function grant(uid, name, privilege, object_type,
                privilege == 'execute' then
                 box.error(box.error.ROLE_GRANTED, name, object_name)
             else
+                if object_type ~= 'universe' then
+                    object_name = string.format(" '%s'", object_name)
+                end
                 box.error(box.error.PRIV_GRANTED, name, privilege,
                           object_type, object_name)
             end

test/box/access.result

@@ -532,7 +532,7 @@ box.space._priv:select{id}
 ...
 box.schema.user.grant('user', 'read', 'universe')
 ---
-- error: User 'user' already has read access on universe ''
+- error: User 'user' already has read access on universe
 ...
 box.space._priv:select{id}
 ---
@@ -738,7 +738,7 @@ box.schema.user.grant('guest', 'read,write,execute', 'universe')
 ...
 box.schema.user.grant('guest', 'read,write,execute', 'universe')
 ---
-- error: User 'guest' already has read,write,execute access on universe ''
+- error: User 'guest' already has read,write,execute access on universe
 ...
 box.schema.user.grant('guest', 'read,write,execute', 'universe', '', { if_not_exists = true })
 ---
@@ -2108,3 +2108,29 @@ box.space._priv:delete{1, 'universe', 0}
 ---
 - error: 'Incorrect grant arguments: can''t revoke universe from the admin user'
 ...
+--
+-- gh-714: box.schema.user.grant error should be versatile,
+-- i.e. error on universally granted privileges shouldn't
+-- include any redundant details and/or symbols.
+--
+box.schema.user.grant('guest', 'read,write,execute', 'universe')
+---
+...
+box.schema.user.grant('guest', 'read,write,execute', 'universe')
+---
+- error: User 'guest' already has read,write,execute access on universe
+...
+-- Expected behavior of grant() error shouldn't change otherwise.
+sp = box.schema.create_space('not_universe')
+---
+...
+box.schema.user.grant('guest', 'read,write,execute', 'space', 'not_universe')
+---
+...
+box.schema.user.grant('guest', 'read,write,execute', 'space', 'not_universe')
+---
+- error: User 'guest' already has read,write,execute access on space 'not_universe'
+...
+sp:drop()
+---
+...

test/box/access.test.lua

@@ -806,3 +806,17 @@ box.schema.user.drop("user3")
 -- instance could not bootstrap nor recovery.
 --
 box.space._priv:delete{1, 'universe', 0}
+
+--
+-- gh-714: box.schema.user.grant error should be versatile,
+-- i.e. error on universally granted privileges shouldn't
+-- include any redundant details and/or symbols.
+--
+box.schema.user.grant('guest', 'read,write,execute', 'universe')
+box.schema.user.grant('guest', 'read,write,execute', 'universe')
+
+-- Expected behavior of grant() error shouldn't change otherwise.
+sp = box.schema.create_space('not_universe')
+box.schema.user.grant('guest', 'read,write,execute', 'space', 'not_universe')
+box.schema.user.grant('guest', 'read,write,execute', 'space', 'not_universe')
+sp:drop()