Sometimes we want to defeat the expression optimizer's ability to
fold constant expressions. A bind variable is a convenient way to
do this, without the complexity of faking a schema and row inputs.
Add a helper to evaluate an expression with bind variable parameters,
doing all the paperwork for us.
A companion make_bind_variable() is added to likewise simplify
creating bind variables for tests.
The CQL protocol and specification call for lists with NULLs in
some places. For example, the statement:
```cql
UPDATE tab
SET x = 3
IF y IN (1, 2, NULL)
WHERE pk = 4
```
has a list `(1, 2, NULL)` that contains NULL. Although the syntax is tuple-like, the value is a list;
consider the same statement as a prepared statement:
```cql
UPDATE tab
SET x = :x
IF y IN :y_values
WHERE pk = :pk
```
`:y_values` must have a list type, since the number of elements is unknown.
Currently, this is done with special paths inside LWT that bypass normal
evaluation, but if we want to unify those paths, we must allow NULLs in
lists (except in storage). This series does that.
Closes#12411
* github.com:scylladb/scylladb:
test: materialized view: add test exercising synthetic empty-type columns
cql3: expr: relax evaluate_list() to allow allow NULL elements
types: allow lists with NULL
test: relax NULL check test predicate
cql3, types: validate listlike collections (sets, lists) for storage
types: make empty type deserialize to non-null value
expression tests often need to create instances of untyped_constant.
Creating them by hand is tedious because the required code is overly verbose.
Having convenience functions for it speeds up test writing.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Tests are similarly relaxed. A test is added in lwt_test to show
that insertion of a list with NULL is still rejected, though we
allow NULLs in IF conditions.
One test is changed from a list of longs to a list of ints, to
prevent churn in the test helper library.
Add a function which creates a mock instance
of data_dictionary::database.
prepare_expression requires a data_dictionary::database
as an argument, so unit tests for it need something
to pass there. make_data_dictionary_database can
be used to create an instance that is sufficient for tests.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
expr_test_utils.hh was a header file with helper methods for
expression tests. All functions were inline, because I didn't
know how to create and link a .cc file in test/boost.
Now the header is split into expr_test_utils.hh and expr_test_utils.cc
and moved to test/lib, which is designed to keep this kind of files.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
