A fix and a test case for Bug#1042798 (box.truncate on non-linear pk)

src/box/box.lua

@@ -244,11 +244,15 @@ function box.on_reload_configuration()
     space_mt.replace = function(space, ...) return box.replace(space.n, ...) end
     space_mt.delete = function(space, ...) return box.delete(space.n, ...) end
     space_mt.truncate = function(space)
-        local pk = space.index[0].idx
-        local part_count = pk:part_count()
-        while #pk > 0 do
-            for k, v in pk.next, pk, nil do
-                space:delete(v:slice(0, part_count))
+        local pk = space.index[0]
+        while #pk.idx > 0 do
+            for _k, t in pk.idx.next, pk.idx, nil do
+                local key = {};
+                -- ipairs does not work because pk.key_field is zero-indexed
+                for _k2, key_field in pairs(pk.key_field) do
+                    table.insert(key, t[key_field.fieldno])
+                end
+                space:delete(unpack(key))
             end
         end
     end

test/big/lua.result

@@ -557,3 +557,37 @@ error: 'Duplicate key exists in unique index 1'
 lua box.space[1]:truncate()
 ---
 ...
+#
+# A test case for Bug #1042798
+# Truncate hangs when primary key is not in linear or starts at the first field
+# https://bugs.launchpad.net/tarantool/+bug/1042798
+#
+lua for k, f in pairs(box.space[23].index[0].key_field) do print(k, ' => ', f.fieldno) end
+---
+0 => 2
+1 => 1
+...
+lua box.insert(23, 1, 2, 3, 4)
+---
+ - 1: {2, 3, 4}
+...
+lua box.insert(23, 10, 20, 30, 40)
+---
+ - 10: {20, 30, 40}
+...
+lua box.insert(23, 20, 30, 40, 50)
+---
+ - 20: {30, 40, 50}
+...
+lua for _k, v in box.space[23]:pairs() do print(v) end
+---
+1: {2, 3, 4}
+10: {20, 30, 40}
+20: {30, 40, 50}
+...
+lua box.space[23]:truncate()
+---
+...
+lua for _k, v in box.space[23]:pairs() do print(v) end
+---
+...

test/big/lua.test

@@ -205,3 +205,20 @@ print """# Test that we print index number in error ER_INDEX_VIOLATION"""
 exec admin "lua box.space[1]:insert(1, 'hello', 'world')"
 exec admin "lua box.space[1]:insert(2, 'hello', 'world')"
 exec admin "lua box.space[1]:truncate()"
+
+print """#
+# A test case for Bug #1042798
+# Truncate hangs when primary key is not in linear or starts at the first field
+# https://bugs.launchpad.net/tarantool/+bug/1042798
+#"""
+
+# Print key fields in pk
+exec admin "lua for k, f in pairs(box.space[23].index[0].key_field) do print(k, ' => ', f.fieldno) end"
+exec admin "lua box.insert(23, 1, 2, 3, 4)"
+exec admin "lua box.insert(23, 10, 20, 30, 40)"
+exec admin "lua box.insert(23, 20, 30, 40, 50)"
+exec admin "lua for _k, v in box.space[23]:pairs() do print(v) end"
+# Truncate must not hang
+exec admin "lua box.space[23]:truncate()"
+# Empty result
+exec admin "lua for _k, v in box.space[23]:pairs() do print(v) end"

test/big/tarantool.cfg

@@ -243,3 +243,12 @@ space[19].index[0].key_field[0].fieldno = 0
 space[19].index[0].key_field[0].type = "NUM"
 space[19].index[0].key_field[1].fieldno = 2
 space[19].index[0].key_field[1].type = "NUM"
+
+# Space #23, https://bugs.launchpad.net/tarantool/+bug/1042798
+space[23].enabled = 1
+space[23].index[0].type = "TREE"
+space[23].index[0].unique = 1
+space[23].index[0].key_field[0].fieldno = 2
+space[23].index[0].key_field[0].type = "NUM"
+space[23].index[0].key_field[1].fieldno = 1
+space[23].index[0].key_field[1].type = "NUM"