Show collation in lua index object

Show collation name (if present) in space.index.name.parts[no].

Fix #2862 part 4

src/box/lua/space.cc

@@ -205,6 +205,11 @@ lbox_fillspace(struct lua_State *L, struct space *space, int i)
 			lua_pushboolean(L, part->is_nullable);
 			lua_setfield(L, -2, "is_nullable");
 
+			if (part->coll != NULL) {
+				lua_pushstring(L, part->coll->name);
+				lua_setfield(L, -2, "collation");
+			}
+
 			lua_settable(L, -3); /* index[k].parts[j] */
 		}
 

test/box/misc.result

@@ -1017,6 +1017,19 @@ not not s:create_index('test3', {parts = {{3, 'string', collation = 'UnIcOdE'}}}
 ---
 - true
 ...
+s:create_index('test4', {parts = {{4, 'string'}}}).parts
+---
+- - type: string
+    is_nullable: false
+    fieldno: 4
+...
+s:create_index('test5', {parts = {{5, 'string', collation = 'Unicode'}}}).parts
+---
+- - type: string
+    is_nullable: false
+    collation: unicode
+    fieldno: 5
+...
 s:drop()
 ---
 ...

test/box/misc.test.lua

@@ -278,4 +278,6 @@ s = box.schema.space.create('test')
 not not s:create_index('test1', {parts = {{1, 'string', collation = 'Unicode'}}})
 not not s:create_index('test2', {parts = {{2, 'string', collation = 'UNICODE'}}})
 not not s:create_index('test3', {parts = {{3, 'string', collation = 'UnIcOdE'}}}) -- I'd prefer to panic on that
+s:create_index('test4', {parts = {{4, 'string'}}}).parts
+s:create_index('test5', {parts = {{5, 'string', collation = 'Unicode'}}}).parts
 s:drop()