Fix case with invalid pagination (#138)

This quite strange that it didn't shoot before.
However, we introduced a merger usage so behaviour was changed a
bit. So pagination over primary key were broken and this patch
fixes it and introduces test for it.

Author: olegrok

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 * Fixed not finding field in tuple on `crud.update` if
   there are `is_nullable` fields in front of it that were added
   when the schema was changed for Tarantool version <= 2.2.
+
+* Pagination over multipart primary key.
 
 ### Added
 

crud/select/comparators.lua

@@ -141,26 +141,16 @@ end
 
 function comparators.gen_func(cmp_operator, key_parts)
     local cmp_func = array_cmp_funcs_by_operators[cmp_operator]
-    if cmp_func == nil then
-        return nil, ComparatorsError:new('Unsupported operator %q', cmp_operator)
-    end
-
-    local func, err = gen_array_cmp_func(cmp_func, key_parts)
-    if err ~= nil then
-        return nil, ComparatorsError:new('Failed to generate comparator function %q', cmp_operator)
-    end
+    ComparatorsError:assert(cmp_func ~= nil, 'Unsupported operator %q', cmp_operator)
 
-    return func
+    return gen_array_cmp_func(cmp_func, key_parts)
 end
 
 function comparators.gen_tuples_comparator(cmp_operator, key_parts, field_names, space_format)
     local updated_key_parts = comparators.update_key_parts_by_field_names(
             space_format, field_names, key_parts
     )
-    local keys_comparator, err = comparators.gen_func(cmp_operator, updated_key_parts)
-    if err ~= nil then
-        return nil, ComparatorsError:new("Failed to generate comparator function: %s", err)
-    end
+    local keys_comparator = comparators.gen_func(cmp_operator, updated_key_parts)
 
     return function(lhs, rhs)
         local lhs_key = utils.extract_key(lhs, updated_key_parts)

crud/select/compat/select_old.lua

@@ -135,12 +135,9 @@ local function build_select_iterator(space_name, user_conditions, opts)
     -- generator of tuples comparator needs field_names and space_format
     -- to update fieldno in each part in cmp_key_parts because storage result contains
     -- fields in order specified by field_names
-    local tuples_comparator, err = select_comparators.gen_tuples_comparator(
+    local tuples_comparator = select_comparators.gen_tuples_comparator(
         cmp_operator, cmp_key_parts, plan.field_names, space_format
     )
-    if err ~= nil then
-        return nil, SelectError:new("Failed to generate comparator function: %s", err)
-    end
 
     -- filter space format by plan.field_names (user defined fields + primary key + scan key)
     -- to pass it user as metadata

crud/select/executor.lua

@@ -1,12 +1,10 @@
 local errors = require('errors')
-local log = require('log')
 
 local dev_checks = require('crud.common.dev_checks')
 local select_comparators = require('crud.select.comparators')
 
 local utils = require('crud.common.utils')
 
-local ScrollToAfterError = errors.new_class('ScrollToAfterError')
 local ExecuteSelectError = errors.new_class('ExecuteSelectError')
 
 local executor = {}
@@ -17,10 +15,7 @@ local function scroll_to_after_tuple(gen, space, scan_index, tarantool_iter, aft
     local scroll_key_parts = utils.merge_primary_key_parts(scan_index.parts, primary_index.parts)
 
     local cmp_operator = select_comparators.get_cmp_operator(tarantool_iter)
-    local scroll_comparator, err = select_comparators.gen_tuples_comparator(cmp_operator, scroll_key_parts)
-    if err ~= nil then
-        return nil, ScrollToAfterError:new("Failed to generate comparator to scroll: %s", err)
-    end
+    local scroll_comparator = select_comparators.gen_tuples_comparator(cmp_operator, scroll_key_parts)
 
     while true do
         local tuple
@@ -59,11 +54,9 @@ function executor.execute(space, index, filter_func, opts)
             value = opts.after_tuple
         else
             local cmp_operator = select_comparators.get_cmp_operator(opts.tarantool_iter)
-            local scan_comparator, err = select_comparators.gen_tuples_comparator(cmp_operator, index.parts)
-            if err ~= nil then
-                log.warn("Failed to generate comparator for scan value: %s", err)
-            elseif scan_comparator(opts.after_tuple, opts.scan_value) then
-                local after_tuple_key = utils.extract_key(opts.after_tuple, index.parts)
+            local scan_comparator = select_comparators.gen_tuples_comparator(cmp_operator, index.parts)
+            local after_tuple_key = utils.extract_key(opts.after_tuple, index.parts)
+            if scan_comparator(after_tuple_key, opts.scan_value) then
                 value = after_tuple_key
             end
         end

test/entrypoint/srv_select.lua

@@ -104,6 +104,28 @@ package.preload['customers-storage'] = function()
                 if_not_exists = true,
             })
 
+            local book_translation = box.schema.space.create('book_translation', {
+                format = {
+                    { name = 'id', type = 'unsigned' },
+                    { name = 'bucket_id', type = 'unsigned' },
+                    { name = 'language', type = 'string' },
+                    { name = 'edition', type = 'integer' },
+                    { name = 'translator', type = 'string' },
+                    { name = 'comments', type = 'string', is_nullable = true },
+                },
+                if_not_exists = true,
+            })
+
+            book_translation:create_index('id', {
+                parts = { 'id', 'language', 'edition' },
+                if_not_exists = true,
+            })
+
+            book_translation:create_index('bucket_id', {
+                parts = { 'bucket_id' },
+                unique = false,
+                if_not_exists = true,
+            })
         end,
     }
 end

test/integration/select_test.lua

@@ -610,6 +610,51 @@ pgroup:add('test_composite_index', function(g)
     t.assert_equals(err, nil)
     local objects = crud.unflatten_rows(result.rows, result.metadata)
     t.assert_equals(objects, helpers.get_objects_by_idxs(customers, {2, 1})) -- in full_name order
+
+    -- first 1
+    local result, err = g.cluster.main_server.net_box:call('crud.select', {'customers', conditions, {first = 1}})
+    t.assert_equals(err, nil)
+    local objects = crud.unflatten_rows(result.rows, result.metadata)
+    t.assert_equals(objects, helpers.get_objects_by_idxs(customers, {2})) -- in full_name order
+
+    -- first 1 with full specified key
+    local result, err = g.cluster.main_server.net_box:call('crud.select',
+            {'customers', {{'==', 'full_name', {'Elizabeth', 'Johnson'}}}, {first = 1}})
+    t.assert_equals(err, nil)
+    local objects = crud.unflatten_rows(result.rows, result.metadata)
+    t.assert_equals(objects, helpers.get_objects_by_idxs(customers, {2})) -- in full_name order
+end)
+
+pgroup:add('test_composite_primary_index', function(g)
+    local book_translation = helpers.insert_objects(g, 'book_translation', {
+        {
+            id = 5,
+            language = 'Ukrainian',
+            edition = 55,
+            translator = 'Mitro Dmitrienko',
+            comments = 'Translation 55',
+        }
+    })
+    t.assert_equals(#book_translation, 1)
+
+    local conditions = {{'=', 'id', {5, 'Ukrainian', 55}}}
+
+    local result, err = g.cluster.main_server.net_box:call('crud.select', {'book_translation', conditions})
+    t.assert_equals(err, nil)
+    t.assert_equals(#result.rows, 1)
+
+    local result, err = g.cluster.main_server.net_box:call('crud.select', {'book_translation', conditions, {first = 2}})
+    t.assert_equals(err, nil)
+    t.assert_equals(#result.rows, 1)
+
+    local result, err = g.cluster.main_server.net_box:call('crud.select', {'book_translation', conditions, {first = 1}})
+    t.assert_equals(err, nil)
+    t.assert_equals(#result.rows, 1)
+
+    local result, err = g.cluster.main_server.net_box:call('crud.select',
+            {'book_translation', conditions, {first = 1, after = result.rows[1]}})
+    t.assert_equals(err, nil)
+    t.assert_equals(#result.rows, 0)
 end)
 
 pgroup:add('test_select_with_batch_size_1', function(g)