Our `null` expression, after the prepare stage, is redundant with a
`constant` expression containing the value NULL.
Remove it. Its role in the unprepared stage is taken over by
untyped_constant, which gains a new type_class enumeration to
represent it.
Some subtleties:
- Usually, handling of null and untyped_constant, or null and constant
was the same, so they are just folded into each other
- LWT "like" operator now has to discriminate between a literal
string and a literal NULL
- prepare and test_assignment were folded into the corresponing
untyped_constant functions. Some care had to be taken to preserve
error messages.
Closes#12118
It's interesting that prepare_expression
for column identifiers doesn't require a receiver.
I hope this won't break validation in the future.
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>
evaluating a bind variable should validate
collection values.
Test that bound collection values are validated,
even in case of a nested collection.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Test that evaluate(tuple_constructor) works
as expected.
It was necessary to implement a custom function
for serializing tuples, because some tests
require the tuple to contain unset_value
or an empty value, which is impossible
to express using the exisiting code.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Test that evaluate(collection_constructor) works as expected.
Added a bunch of utility methods for creating
collection values to expr_test_utils.hh.
I was forced to write custom serialization of
collections. I tried to use data_value,
but it doesn't allow to express unset_value
and empty values.
The custom serialization isnt actually used
in this specific commit, but it's needed
in the following ones.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Add tests which test that evaluate(column_value)
and evaluate(bind_variable) work as expected.
values of columns and bind variables are
kept in evaluation_inputs, so we need to mock
them in order for evaluate() to work.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Add unit test for evaluating expr::constant values.
evaluate(constant) just returns constant.value,
so there is no point in trying all the possible combinations.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Add a header file which will contain
utilities for writing expression tests.
For now it contains simple functions
like make_int_constant(), but there
are many more to come.
I feel like it's cleaner to put
all these functions in a separate
file instead of having them spread randomly
between tests.
It also enables code reuse so that
future expression tests can reuse
these functions instead of writing
them from scratch.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
When analyzing a WHERE clause, we want to separate individual
factors (usually relations), and later partition them into
partition key, clustering key, and regular column relations. The
first step is separation, for which this helper is added.
Currently, it is not required since the grammar supplies the
expression in separated form, but this will not work once it is
relaxed to allow any expression in the WHERE clause.
A unit test is added.
An expr::constant is an expression that happens to represent a constant,
so it's too heavyweight to be used for evaluation. Right now the extra
weight is just a type (which causes extra work by having to maintain
the shared_ptr reference count), but it will grow in the future to include
source location (for error reporting) and maybe other things.
Prior to e9b6171b5 ("Merge 'cql3: expr: unify left-hand-side and
right-hand-side of binary_operator prepares' from Avi Kivity"), we had
to use expr::constant since there was not enough type infomation in
expressions. But now every expression carries its type (in programming
language terms, expressions are now statically typed), so carrying types
in values is not needed.
So change evaluate() to return cql3::raw_value. The majority of the
patch just changes that. The rest deals with some fallout:
- cql3::raw_value gains a view() helper to convert to a raw_value_view,
and is_null_or_unset() to match with expr::constant and reduce further
churn.
- some helpers that worked on expr::constant and now receive a
raw_value now need the type passed via an additional argument. The
type is computed from the expression by the caller.
- many type checks during expression evaluation were dropped. This is
a consequence of static typing - we must trust the expression prepare
phase to perform full type checking since values no longer carry type
information.
Closes#10797
shape_type was used in prepare_expression to differentiate
between a few cases and create the correct receivers.
This was used by the relation class.
Now creating the correct receiver has been delegated to the caller
of prepare_expression and all bind_variables can be handled
in the same simple way.
shape_type is not needed anymore.
Not having it is better because it simplifies things.
Signed-off-by: cvybhu <jan.ciolek@scylladb.com>
Now that parser outputs expressions
it's much easier to check whether
expression printer works correctly.
We can prepare a bunch of strings
which will be parsed and then printed
back to string.
Then we can compare those strings.
It's much easier than creating
expresions to print manually.
The only downside is that this tests
only unprepared version of expression,
so instead of column_value there will
be unresolved identifier, insted of constant
untyped_constant etc.
Signed-off-by: cvybhu <jan.ciolek@scylladb.com>
expression::printer is used to print CQL expressions
in a pretty way that allows them to be parsed back
to the same representation.
There is a bunch of things that need to be changed when
compared to the current implementation of opreatorr<<(expression)
to output something parsable.
column names should be printed without 'unresolved_identifier()'
and sometimes they need to be quoted to perserve case sensitivity.
I needed to write new code for printing constant values
because the current one did debug printing
(e.g. a set was printed as '1; 2; 3').
A list of IN values should be printed inside () intead of [],
but because it is internally represented as a list it is
by default printed with [].
To fix this a temporary tuple_constructor is created and printed.
Signed-off-by: cvybhu <jan.ciolek@scylladb.com>
Adds a test with a vistior that can only be used as a rvalue.
Without std::forward in expr::visit this test doesn't compile.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Add tests for new expr::visit to ensure that it is working correctly.
expr::visit had a hidden bug where trying to return a reference
actually returned a reference to freed location on the stack,
so now there are tests to ensure that everything works.
Sadly the test `expr_visit_const_ref` also passes
before the fix, but at lest expr_visit_ref doesn't compile before the fix.
It would be better to test this by taking references returned
by std::visit and expr::visit and checking that they point
to the same address in memory, but I can't do this
because I would have to access private field of expression.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
