Module validate 

Positioned, reusable schema validation — the single semantic-diagnostics authority for a parsed Schema.

Why this lives in forgedb-parser

Schema validation logically belongs next to the diagnostic vocabulary (ValidationError / Position) in [forgedb-validation], and epic #173 (WS2b) originally proposed extending that crate. But forgedb-validation cannot see the Schema AST: forgedb-parser already depends on forgedb-validation (for Position/ValidationError), so a reverse dependency would be a cycle. The AST lives here, so the walk that validates it lives here too — reusing the diagnostic types and naming predicates from forgedb-validation. The split is: validation crate = diagnostic types + reusable predicates; parser = the AST and the walk that applies them.

The single authority

validate_schema is the one implementation of ForgeDB’s schema-level semantic rules. It is consumed by:

• the parser itself (crate::Parser::parse runs it fail-fast to preserve its Result<Schema, String> contract), and
• the CLI forgedb validate command and the LSP, which call it directly on a Parser::parse_unvalidated AST to surface all diagnostics with positions instead of just the first.

Everything it reports is a property of the assembled Schema (names, duplicates, cross-references, type constraints). Purely syntactic errors (unexpected tokens, malformed directives, empty models, composite-index arity) remain fatal in the parser’s structural pass and never reach here.

Callers that also need filesystem checks (component-file existence) or advisory lints (no id / no timestamp) layer those on top — those are not pure-schema diagnostics and stay in the CLI.

Functions

collect_naming_errors

Naming-convention diagnostics: PascalCase model/struct/enum names and enum variants, snake_case field names.

collect_structure_errors

Structural / reference diagnostics: duplicate names (model/struct/enum, fields within a container, enum variants), relation targets resolve, struct/enum type references resolve, structs contain only fixed-size types, and composite-index / projection field references exist.

validate_schema

Run the full positioned semantic validation of a parsed schema and return every diagnostic (naming + structural). Does not fail fast.