Documentation
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Overview ¶
Package equiv implements a build-time DIFFERENTIAL equivalence gate for the optional-filters feature. Given a canonical query (with N optional equality clauses) and the 2^N constant-folded variants produced by the analyzer, it proves each variant equivalent to the canonical query by EXECUTING BOTH against a fresh in-process modernc SQLite seeded with a small deterministic dataset and asserting identical result rows.
This is differential (empirical) equivalence, NOT formal/SMT equivalence: it demonstrates the variant and the canonical agree on the seeded sample (which is chosen to cover NULL/non-NULL and boundary values for the filtered columns), and catches the realistic fold bugs (a dropped predicate, a wrong comparison operator, an off-by-one boundary). It does not prove equivalence over all possible databases. The seed is fully deterministic — no randomness — so a pass or failure is reproducible and the build is stable.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Param ¶
type Param struct {
// Name is the SQL named-param name (without the leading "@"), e.g. "min_age".
Name string
// Column is the filtered column the param compares against, e.g. "age". Used to
// pick boundary trial values from the seeded data.
Column string
// GoType is the resolved Go scalar type, used to choose representative trial
// values ("string" vs integer vs float).
GoType string
}
Param is one optional equality-filter param.
type Report ¶
type Report struct {
Mismatches []Mismatch
}
Report is the result of Check: a (possibly empty) list of mismatches.
func Check ¶
Check runs the differential equivalence gate for spec against catalog. It opens a fresh in-memory SQLite, loads the catalog DDL, seeds a deterministic sample dataset, then for each variant runs canonical-vs-variant over a set of trial param values and records any divergence. A non-nil error means the check could not be performed (e.g. a SQL prepare error); rows differing is reported via the Report, not the error.
type Spec ¶
type Spec struct {
// CanonicalSQL is the original query with all N optional clauses present, using
// @name-style named params for the optional filters (and any required params).
CanonicalSQL string
// Optional lists the optional equality-filter params, in bit order: bit i of a
// variant Mask corresponds to Optional[i].
Optional []Param
// Variants are the constant-folded variants, one per subset of Optional.
Variants []Variant
}
Spec is the input to Check: a canonical query plus its folded variants and the optional params they fold over.
type Variant ¶
type Variant struct {
// Mask identifies the subset of Optional present in this variant.
Mask int
// SQL is the folded statement referencing only the present optional params.
SQL string
// Present are the names (matching Param.Name) of the optional params kept in
// this variant, in bind order.
Present []string
}
Variant is one constant-folded SQL variant.
Source Files