coop/rose-ash
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

datalog: stratifier rejects recursion through aggregation (165/165)
Some checks failed
Test, Build, and Deploy / test-build-deploy (push) Failing after 53s
Details

Browse Source 
Bug: dl-check-stratifiable iterated body literals looking only for
explicit :neg literals, missing aggregate cycles. Now also walks
aggregates via dl-aggregate-dep-edge — q(N) :- count(N, X, q(X))
correctly errors out at saturation time.

3 new tests cover:
- recursion-through-aggregation rejected
- negation + aggregation coexist when in different strata
- min over empty derived relation produces no result
This commit is contained in:
giles
2026-05-08 09:13:10 +00:00
parent a63d67247a
commit b95d8c5a63
5 changed files with 76 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
lib/datalog/strata.sx
View File

@@ -197,18 +197,33 @@
(for-each
(fn
(lit)
(when
(and (dict? lit) (has-key? lit :neg))
(let ((tgt (dl-rel-name (get lit :neg))))
(when
(and (not (nil? tgt))
(dl-reach-cycle? reach head-rel tgt))
(set!
err
(str "non-stratifiable: relation " head-rel
" transitively depends through negation on "
tgt
" which depends back on " head-rel))))))
(cond
((and (dict? lit) (has-key? lit :neg))
(let ((tgt (dl-rel-name (get lit :neg))))
(when
(and (not (nil? tgt))
(dl-reach-cycle? reach head-rel tgt))
(set!
err
(str "non-stratifiable: relation " head-rel
" transitively depends through negation on "
tgt
" which depends back on " head-rel)))))
((dl-aggregate? lit)
(let ((edge (dl-aggregate-dep-edge lit)))
(when
(not (nil? edge))
(let ((tgt (get edge :rel)))
(when
(and (not (nil? tgt))
(dl-reach-cycle? reach head-rel tgt))
(set!
err
(str "non-stratifiable: relation "
head-rel
" aggregates over " tgt
" which depends back on "
head-rel)))))))))
(get rule :body)))))
(dl-rules db))
err)))))