feat(gfql): same-path WHERE executor (restack)

[lmeyerov]

Summary

• add same-path WHERE executor (df_executor + same_path modules)
• add list-form g.gfql([...], where=...) support and empty-chain guard
• add extensive GFQL WHERE tests and mypy/lint fixes

Status

• Restack complete; supersedes feat(gfql): add same-path WHERE executor #912 (stack-merged)
• Base: master

Testing

• uv run python -m pytest graphistry/tests/compute/test_chain_where.py -q
• uv run env PYTHONPATH=. python -m pytest tests/gfql/ref/test_df_executor_patterns.py -q

WHERE Examples

• imports

from graphistry.compute import n, e_forward
from graphistry.compute.gfql.same_path_types import col, compare

• Equality across node aliases:
  • g.gfql([n(name="a"), e_forward(name="r"), n(name="c")], where=[compare(col("a", "owner_id"), "==", col("c", "id"))])
• Inequality across node aliases:
  • g.gfql([n(name="start"), e_forward(), n(name="end")], where=[compare(col("start", "score"), "<", col("end", "score"))])
• Edge-to-edge comparison in a multi-edge chain:
  • g.gfql([n(name="a"), e_forward(name="e1"), n(name="b"), e_forward(name="e2"), n(name="c")], where=[compare(col("e1", "weight"), ">=", col("e2", "weight"))])
• JSON/dict form (API/serialized usage):
  • {"chain": [...], "where": [{"eq": {"left": "a.owner_id", "right": "c.id"}}, {"gt": {"left": "start.score", "right": "end.score"}}]}

[lmeyerov]

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