ABI Layer 3: NullSafe (level 4) — a deeper, context-sensitive query-safety checker#37
Merged
Merged
Conversation
…uarantee
Continues the flagship semantic-proof coverage (InjectionFree level 5,
SchemaBound level 2) with TypeCompat (level 3: "operand types compatible").
Adds `Typedqliser.ABI.TypeCompat`, to the same quality bar:
* a small SQL type universe (`SqlType`) and a typed column environment
(`ColEnv`) with a total `lookupType` resolver, reusing the existing
`Query`/`Pred`/`Value` AST;
* `ValueCompat`/`PredTypeCompat`/`QueryTypeCompat` — the proposition that
every WHERE comparison compares a column against a value of a matching
type (a bound parameter adopts the column's type; a literal is TInt; a
raw splice is TText). There is no constructor for a type clash, so a
mismatched comparison is uninhabited;
* `decQueryTypeCompat` — a sound + complete `Dec`, so a "Proven" TypeCompat
certificate is backed by a constructive witness and a type clash can
never be certified;
* `certifyTypeCompatSound` (a `Proven` verdict provably entails the
property); `typeCompatIsLevelThree : levelNat TypeCompat = 3`;
* positive control (a well-typed query, with the certifier computing to
`Proven`) and negative control (`name : Text` compared to an integer
literal provably cannot be certified).
Verified with idris2 0.7.0: `idris2 --build typedqliser-abi.ipkg` exits 0 with
zero warnings (all 7 modules). Adversarially checked — three deliberately-false
proofs (wrong level ordinal, a TInt literal certified against a TText column,
and a type-compatible witness for the clash query) are all rejected by the
type checker.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Adds Typedqliser.ABI.Invariants, a second, deeper, distinct machine-checked property over the existing Semantics query model (Query/Pred/Value reused verbatim). Where the Layer-2 flagship (Semantics.InjectionFree, level 5) is a purely structural property, NullSafe (level 4) is context-sensitive: a projected nullable column is safe only if the WHERE predicate guards it, with guards discovered by union under And and intersection under Or (disjunctive weakening). Includes a sound + complete decision procedure (decQueryNullSafe : Dec ...), a certifier proven sound (certifyNullSafeSound), the level-ordinal identity plus a proof it differs from InjectionFree, three positive controls and three non-vacuity controls (unguarded projection, And/union, Or/intersection). Builds clean with zero warnings; the deliberately-false adversarial proof is rejected. No believe_me/postulate/assert_total/%hint; %default total throughout. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Layer 3 (second, deeper invariant): adds NullSafe (level 4) as a real checker over the existing Layer-2 query AST. A projected nullable column is null-safe iff the WHERE predicate guards it — with guards discovered by union under
Andand intersection underOr(disjunctive weakening). Context-sensitive and distinct from the structural InjectionFree (level 5)/SchemaBound/TypeCompat checkers.New module
Typedqliser.ABI.Invariants(imports the Layer-2Semanticsmodel):QueryNullSafe, sound+completedecQueryNullSafe,certifyNullSafeSound, level identity (= 4), 3 positive + 3 non-vacuity controls.Testing
Idris2 0.7.0
--build→ exit 0, zero warnings (8 modules). Adversarial: a falseGuardedwitness for an unguarded query was rejected.build/removed. Nobelieve_me/postulate/sorry.🤖 Generated with Claude Code
https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Generated by Claude Code