MATCH property constraints fail when a variable is referenced more than once.

[dehowef]

Describe the bug
Property Constraints throw an error when they are applied to a variable mentioned more than once.

How are you accessing AGE (Command line, driver, etc.)?
Commandline through postgresql.

What data setup do we need to do?
None

What is the necessary configuration info needed?

• Install Postgresql
• Install AGE

What is the command that caused the error?

SELECT * from cypher('my_graph_name', $$
  MATCH (a {prop: “val”})-[]- (a {prop2: “val2”})
$$) as (a agtype);

postgres=# SELECT * FROM cypher('pilots', $$ MATCH(a{prop:"val"})-[]-(a{prop2:"val2"}) RETURN a $$ ) AS (a agtype);
2023-03-03 09:05:16.444 PST [145400] ERROR:  variable a already exists at character 59
2023-03-03 09:05:16.444 PST [145400] STATEMENT:  SELECT * FROM cypher('pilots', $$ MATCH(a{prop:"val"})-[]-(a{prop2:"val2"}) RETURN a $$ ) AS (a agtype);
ERROR:  variable a already exists
LINE 1: ... FROM cypher('pilots', $$ MATCH(a{prop:"val"})-[]-(a{prop2:"...

Expected behavior
The property constraint must be evaluated.

Environment (please complete the following information):

• Version: 1.2.0

[Zainab-Saad]

This probably is not the bug rather the MATCH clause using same variable for the two vertices should be used to match self-loop on a vertex. MATCH(a)-[]-(a) and MATCH(a {prop: "value"})-[]-(a) would work fine as they are used for matching the self-loop but MATCH(a {prop :"value1")-[]-(a {prop : "value2"}) or MATCH(a {prop1 : "value1"})-[]-(a {prop2 : "value2"}) would through an error below as they are not matching any self-loop (because the properties are different for two vertices)

ERROR: variable a already exists

[dehowef]

This probably is not the bug rather the MATCH clause using same variable for the two vertices should be used to match self-loop on a vertex. MATCH(a)-[]-(a) and MATCH(a {prop: "value"})-[]-(a) would work fine as they are used for matching the self-loop but MATCH(a {prop :"value1")-[]-(a {prop : "value2"}) or MATCH(a {prop1 : "value1"})-[]-(a {prop2 : "value2"}) would through an error below as they are not matching any self-loop (because the properties are different for two vertices)

ERROR: variable a already exists

Respectfully, you are incorrect and it's a bug. Thank you

[dehowef]

This probably is not the bug rather the MATCH clause using same variable for the two vertices should be used to match self-loop on a vertex. MATCH(a)-[]-(a) and MATCH(a {prop: "value"})-[]-(a) would work fine as they are used for matching the self-loop but MATCH(a {prop :"value1")-[]-(a {prop : "value2"}) or MATCH(a {prop1 : "value1"})-[]-(a {prop2 : "value2"}) would through an error below as they are not matching any self-loop (because the properties are different for two vertices)

ERROR: variable a already exists

When a property constraint is placed on a variable, it is applied to the variable at hand. MATCH(a {prop :"value1")-[]-(a {prop : "value2"}) and MATCH(a {prop :"value1", prop2 : "value2"})-[]-(a ) are functionally equivalent and valid queries, what changes is the position with which the property constraint is being declared. A node can have many properties stored within them, and the variable declaration, in this case 'a', denotes that they should be the same vertex within this pattern.

If there is nothing returned by the pattern then it should return nothing rather than an error message.