Fix Issue 1884: Ambiguous column reference and invalid AGT header
errors.

Note: This PR was created with AI tools and a human, or 2.

This commit addresses two related bugs that occur when using SET to store
graph elements (vertices, edges, paths) as property values:

Issue 1884 - "column reference is ambiguous" error:
When a Cypher query uses the same variable in both the SET expression RHS
and the RETURN clause (e.g., SET n.prop = n RETURN n), PostgreSQL would
report "column reference is ambiguous" because the variable appeared in
multiple subqueries without proper qualification.

Solution: The fix for this issue was already in place through the target
entry naming scheme that qualifies column references.

"Invalid AGT header value" offset error:
When deserializing nested VERTEX, EDGE, or PATH values stored in properties,
the system would fail with errors like "Invalid AGT header value: 0x00000041".
This occurred because ag_serialize_extended_type() did not include alignment
padding (padlen) in the agtentry length calculation for these types, while
fill_agtype_value() uses INTALIGN() when reading, causing offset mismatch.

Solution: Modified ag_serialize_extended_type() in agtype_ext.c to include
padlen in the agtentry length for VERTEX, EDGE, and PATH cases, matching
the existing pattern used for INTEGER, FLOAT, and NUMERIC types:

    *agtentry = AGTENTRY_IS_AGTYPE | (padlen + (AGTENTRY_OFFLENMASK & ...));

This ensures the serialized length accounts for alignment padding, allowing
correct deserialization of nested graph elements.

Appropriate regression tests were added to verify the fixes.

Co-authored by: Zainab Saad <105385638+Zainab-Saad@users.noreply.github.com>

modified:   regress/expected/cypher_set.out
modified:   regress/sql/cypher_set.sql
modified:   src/backend/parser/cypher_clause.c
modified:   src/backend/utils/adt/agtype_ext.c

Fix Issue 1884: Ambiguous column reference and invalid AGT header
errors.

Note: This PR was created with AI tools and a human, or 2.

This commit addresses two related bugs that occur when using SET to store
graph elements (vertices, edges, paths) as property values:

Issue 1884 - "column reference is ambiguous" error:
When a Cypher query uses the same variable in both the SET expression RHS
and the RETURN clause (e.g., SET n.prop = n RETURN n), PostgreSQL would
report "column reference is ambiguous" because the variable appeared in
multiple subqueries without proper qualification.

Solution: The fix for this issue was already in place through the target
entry naming scheme that qualifies column references.

"Invalid AGT header value" offset error:
When deserializing nested VERTEX, EDGE, or PATH values stored in properties,
the system would fail with errors like "Invalid AGT header value: 0x00000041".
This occurred because ag_serialize_extended_type() did not include alignment
padding (padlen) in the agtentry length calculation for these types, while
fill_agtype_value() uses INTALIGN() when reading, causing offset mismatch.

Solution: Modified ag_serialize_extended_type() in agtype_ext.c to include
padlen in the agtentry length for VERTEX, EDGE, and PATH cases, matching
the existing pattern used for INTEGER, FLOAT, and NUMERIC types:

    *agtentry = AGTENTRY_IS_AGTYPE | (padlen + (AGTENTRY_OFFLENMASK & ...));

This ensures the serialized length accounts for alignment padding, allowing
correct deserialization of nested graph elements.

Appropriate regression tests were added to verify the fixes.

Co-authored by: Zainab Saad <105385638+Zainab-Saad@users.noreply.github.com>

modified:   regress/expected/cypher_set.out
modified:   regress/sql/cypher_set.sql
modified:   src/backend/parser/cypher_clause.c
modified:   src/backend/utils/adt/agtype_ext.c

Fix Issue 1884: Ambiguous column reference and invalid AGT header
errors.

Note: This PR was created with AI tools and a human, or 2.

This commit addresses two related bugs that occur when using SET to store
graph elements (vertices, edges, paths) as property values:

Issue 1884 - "column reference is ambiguous" error:
When a Cypher query uses the same variable in both the SET expression RHS
and the RETURN clause (e.g., SET n.prop = n RETURN n), PostgreSQL would
report "column reference is ambiguous" because the variable appeared in
multiple subqueries without proper qualification.

Solution: The fix for this issue was already in place through the target
entry naming scheme that qualifies column references.

"Invalid AGT header value" offset error:
When deserializing nested VERTEX, EDGE, or PATH values stored in properties,
the system would fail with errors like "Invalid AGT header value: 0x00000041".
This occurred because ag_serialize_extended_type() did not include alignment
padding (padlen) in the agtentry length calculation for these types, while
fill_agtype_value() uses INTALIGN() when reading, causing offset mismatch.

Solution: Modified ag_serialize_extended_type() in agtype_ext.c to include
padlen in the agtentry length for VERTEX, EDGE, and PATH cases, matching
the existing pattern used for INTEGER, FLOAT, and NUMERIC types:

    *agtentry = AGTENTRY_IS_AGTYPE | (padlen + (AGTENTRY_OFFLENMASK & ...));

This ensures the serialized length accounts for alignment padding, allowing
correct deserialization of nested graph elements.

Appropriate regression tests were added to verify the fixes.

Co-authored by: Zainab Saad <105385638+Zainab-Saad@users.noreply.github.com>

modified:   regress/expected/cypher_set.out
modified:   regress/sql/cypher_set.sql
modified:   src/backend/parser/cypher_clause.c
modified:   src/backend/utils/adt/agtype_ext.c

Fix Issue 1884: Ambiguous column reference and invalid AGT header
errors.

Note: This PR was created with AI tools and a human, or 2.

This commit addresses two related bugs that occur when using SET to store
graph elements (vertices, edges, paths) as property values:

Issue 1884 - "column reference is ambiguous" error:
When a Cypher query uses the same variable in both the SET expression RHS
and the RETURN clause (e.g., SET n.prop = n RETURN n), PostgreSQL would
report "column reference is ambiguous" because the variable appeared in
multiple subqueries without proper qualification.

Solution: The fix for this issue was already in place through the target
entry naming scheme that qualifies column references.

"Invalid AGT header value" offset error:
When deserializing nested VERTEX, EDGE, or PATH values stored in properties,
the system would fail with errors like "Invalid AGT header value: 0x00000041".
This occurred because ag_serialize_extended_type() did not include alignment
padding (padlen) in the agtentry length calculation for these types, while
fill_agtype_value() uses INTALIGN() when reading, causing offset mismatch.

Solution: Modified ag_serialize_extended_type() in agtype_ext.c to include
padlen in the agtentry length for VERTEX, EDGE, and PATH cases, matching
the existing pattern used for INTEGER, FLOAT, and NUMERIC types:

    *agtentry = AGTENTRY_IS_AGTYPE | (padlen + (AGTENTRY_OFFLENMASK & ...));

This ensures the serialized length accounts for alignment padding, allowing
correct deserialization of nested graph elements.

Appropriate regression tests were added to verify the fixes.

Co-authored by: Zainab Saad <105385638+Zainab-Saad@users.noreply.github.com>

modified:   regress/expected/cypher_set.out
modified:   regress/sql/cypher_set.sql
modified:   src/backend/parser/cypher_clause.c
modified:   src/backend/utils/adt/agtype_ext.c

Fix Issue 1884: Ambiguous column reference and invalid AGT header
errors.

Note: This PR was created with AI tools and a human, or 2.

This commit addresses two related bugs that occur when using SET to store
graph elements (vertices, edges, paths) as property values:

Issue 1884 - "column reference is ambiguous" error:
When a Cypher query uses the same variable in both the SET expression RHS
and the RETURN clause (e.g., SET n.prop = n RETURN n), PostgreSQL would
report "column reference is ambiguous" because the variable appeared in
multiple subqueries without proper qualification.

Solution: The fix for this issue was already in place through the target
entry naming scheme that qualifies column references.

"Invalid AGT header value" offset error:
When deserializing nested VERTEX, EDGE, or PATH values stored in properties,
the system would fail with errors like "Invalid AGT header value: 0x00000041".
This occurred because ag_serialize_extended_type() did not include alignment
padding (padlen) in the agtentry length calculation for these types, while
fill_agtype_value() uses INTALIGN() when reading, causing offset mismatch.

Solution: Modified ag_serialize_extended_type() in agtype_ext.c to include
padlen in the agtentry length for VERTEX, EDGE, and PATH cases, matching
the existing pattern used for INTEGER, FLOAT, and NUMERIC types:

    *agtentry = AGTENTRY_IS_AGTYPE | (padlen + (AGTENTRY_OFFLENMASK & ...));

This ensures the serialized length accounts for alignment padding, allowing
correct deserialization of nested graph elements.

Appropriate regression tests were added to verify the fixes.

Co-authored by: Zainab Saad <105385638+Zainab-Saad@users.noreply.github.com>

modified:   regress/expected/cypher_set.out
modified:   regress/sql/cypher_set.sql
modified:   src/backend/parser/cypher_clause.c
modified:   src/backend/utils/adt/agtype_ext.c