ABI Layer 4: prove the FFI result-code seam is injective + faithful#38
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…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
Prove the FFI result-code encoding is SOUND: the C integer the Zig FFI returns faithfully round-trips back to the ABI value, and distinct ABI outcomes never collide on the wire. - intToResult / intToStatus: total decoders (if x == n over boolean Bits32 ==, which reduces on concrete literals). - resultRoundTrip / statusRoundTrip: lossless encoding, proved by Refl. - resultToIntInjective / statusToIntInjective: injectivity DERIVED from the round-trip via a local justInj + cong. - Positive controls (decodeOk/decodeNullPointer/decodeUnknown/decodeProven) and machine-checked non-vacuity controls (okNotError, schemaNotNull, provenNotRefuted) refuting collisions of distinct codes. Genuine total proof: no believe_me / postulate / assert_total / sorry. Builds clean with zero warnings; a false seam claim is rejected by --check. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>
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Summary
Layer 4 (seal the ABI↔FFI seam): proves the FFI result-code encoding (
resultToInt) is a sound, lossless wire encoding — decoderintToResultwithresultRoundTrip, from whichresultToIntInjectiveis derived. Distinct ABI outcomes never collide on the C wire. Complements the structuralabi-ffi-gate.py.New module
Typedqliser.ABI.FfiSeam(importsTypes). Positive + non-vacuity controls.Testing
Idris2 0.7.0
--build→ exit 0, zero warnings (9 modules). Adversarial rejection confirmed.build/removed. Nobelieve_me/postulate/sorry.🤖 Generated with Claude Code
https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx
Generated by Claude Code