fix: thread dialect through schemaOrEmpty into all six native handlers

The dialect parameter was passed through the tool layer but dropped at
the schema resolution step. Six native handlers (validate, check, fix,
semantics, equivalence, correct) called schemaOrEmpty() without dialect,
so the fallback empty schema always used the default dialect.

Fix: add optional dialect param to schemaOrEmpty() and pass it to
Schema.fromDdl(). Update all six handlers to forward params.dialect.

Co-Authored-By: Vijay Yadav <vjyadav194@gmail.com>

Author: VJ-yadav

packages/opencode/src/altimate/native/altimate-core.ts

@@ -88,7 +88,7 @@ export function registerAll(): void {
   // 1. altimate_core.validate
   register("altimate_core.validate", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const raw = await core.validate(params.sql, schema)
       const data = toData(raw)
       return ok(true, data)
@@ -167,7 +167,7 @@ export function registerAll(): void {
   // 6. altimate_core.check — composite: validate + lint + scan_sql
   register("altimate_core.check", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const validation = await core.validate(params.sql, schema)
       const lintResult = core.lint(params.sql, schema)
       const safety = core.scanSql(params.sql)
@@ -185,7 +185,7 @@ export function registerAll(): void {
   // 7. altimate_core.fix
   register("altimate_core.fix", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const raw = await core.fix(params.sql, schema, params.max_iterations ?? undefined)
       const data = toData(raw)
       return ok(true, data)
@@ -209,7 +209,7 @@ export function registerAll(): void {
   // 9. altimate_core.semantics
   register("altimate_core.semantics", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const raw = await core.checkSemantics(params.sql, schema)
       const data = toData(raw)
       return ok(true, data)
@@ -232,7 +232,7 @@ export function registerAll(): void {
   // 11. altimate_core.equivalence
   register("altimate_core.equivalence", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const raw = await core.checkEquivalence(params.sql1, params.sql2, schema)
       const data = toData(raw)
       return ok(true, data)
@@ -280,7 +280,7 @@ export function registerAll(): void {
   // 15. altimate_core.correct
   register("altimate_core.correct", async (params) => {
     try {
-      const schema = schemaOrEmpty(params.schema_path, params.schema_context)
+      const schema = schemaOrEmpty(params.schema_path, params.schema_context, params.dialect)
       const raw = await core.correct(params.sql, schema)
       const data = toData(raw)
       return ok(true, data)

packages/opencode/src/altimate/native/schema-resolver.ts

@@ -111,12 +111,15 @@ export function resolveSchema(
 /**
  * Resolve a Schema, falling back to a minimal empty schema when none is provided.
  * Use this for functions that require a non-null Schema argument.
+ * When a dialect is provided, it is passed to Schema.fromDdl() so the fallback
+ * empty schema uses the correct SQL dialect for validation/analysis.
  */
 export function schemaOrEmpty(
   schemaPath?: string,
   schemaContext?: Record<string, any>,
+  dialect?: string,
 ): Schema {
   const s = resolveSchema(schemaPath, schemaContext)
   if (s !== null) return s
-  return Schema.fromDdl("CREATE TABLE _empty_ (id INT);")
+  return Schema.fromDdl("CREATE TABLE _empty_ (id INT);", dialect || undefined)
 }