Implement is set operator

[rareMaxim]

Description of the issue

In Virtual DocType filters "is set" and "is not set" not working.

Context information (for bug reports)

for example i see https://github.com/frappe/frappe/blob/develop/frappe/core/doctype/recorder/recorder.py#L67

this method call evaluate_filters(req, filters)]. Open this method:

frappe/frappe/utils/data.py

Line 1958 in 81785ae

if not compare(doc.get(f.fieldname), f.operator, f.value, f.fieldtype):

and we see its use operator_map dictionary

frappe/frappe/utils/data.py

Line 1933 in 81785ae

operator_map = {

. In this dictionary not operators "is set" and "is not set"

Output of bench version

(paste here)

Steps to reproduce the issue

1. Create Virtual DocType
2. Try use filter Is Set and Is Not Set

Observed result

Expected result

Stacktrace / full error message

(paste here)

Additional information

OS version / distribution, Frappe install method, etc.

[ankush]

If someone wants to take a stab at this:

• is set means some value is set. For nullable fields this means value is None or falsy like empty string. For numeric fields this doesn't make sense. is not set is just opposite of it.

[rareMaxim]

Anybody, pls add in

frappe/frappe/utils/data.py

Line 1933 in 81785ae

operator_map = {

line:

"is": lambda a, b: (a and (b == 'set')) or (not a and (b == 'not set')),

total:

operator_map = {
	# startswith
	"^": lambda a, b: (a or "").startswith(b),
	# in or not in a list
	"in": lambda a, b: operator.contains(b, a),
	"not in": lambda a, b: not operator.contains(b, a),
	# comparison operators
	"=": operator.eq,
	"!=": operator.ne,
	">": operator.gt,
	"<": operator.lt,
	">=": operator.ge,
	"<=": operator.le,
	"not None": lambda a, b: a is not None,
	"None": lambda a, b: a is None,
	"like": sql_like,
	"not like": lambda a, b: not sql_like(a, b),
	"is": lambda a, b: (a and (b == 'set')) or (not a and (b == 'not set')),
}