From c567636deb655415c1fce8daa323d18a22a892ae Mon Sep 17 00:00:00 2001
From: pedrocarlo <pedro.muniz.carlo@gmail.com>
Date: Mon, 21 Jul 2025 22:27:42 -0300
Subject: [PATCH] Adjust Transaction OpCode to accept schema cookie + check if
 cookie changed

---
 core/translate/mod.rs         |  4 +++-
 core/translate/transaction.rs |  8 +++++++-
 core/vdbe/builder.rs          |  7 ++++++-
 core/vdbe/execute.rs          | 11 ++++++++++-
 core/vdbe/explain.rs          |  4 ++--
 core/vdbe/insn.rs             |  5 +++--
 6 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/core/translate/mod.rs b/core/translate/mod.rs
index badbaac3b..e3a2eb940 100644
--- a/core/translate/mod.rs
+++ b/core/translate/mod.rs
@@ -123,7 +123,9 @@ pub fn translate_inner(
         ast::Stmt::Attach { expr, db_name, key } => {
             attach::translate_attach(&expr, &db_name, &key, schema, syms, program)?
         }
-        ast::Stmt::Begin(tx_type, tx_name) => translate_tx_begin(tx_type, tx_name, program)?,
+        ast::Stmt::Begin(tx_type, tx_name) => {
+            translate_tx_begin(tx_type, tx_name, &schema, program)?
+        }
         ast::Stmt::Commit(tx_name) => translate_tx_commit(tx_name, program)?,
         ast::Stmt::CreateIndex {
             unique,
diff --git a/core/translate/transaction.rs b/core/translate/transaction.rs
index 47fdc3df8..8a4e6ab21 100644
--- a/core/translate/transaction.rs
+++ b/core/translate/transaction.rs
@@ -1,3 +1,4 @@
+use crate::schema::Schema;
 use crate::translate::{ProgramBuilder, ProgramBuilderOpts};
 use crate::vdbe::insn::Insn;
 use crate::Result;
@@ -6,6 +7,7 @@ use turso_sqlite3_parser::ast::{Name, TransactionType};
 pub fn translate_tx_begin(
     tx_type: Option<TransactionType>,
     _tx_name: Option<Name>,
+    schema: &Schema,
     mut program: ProgramBuilder,
 ) -> Result<ProgramBuilder> {
     program.extend(&ProgramBuilderOpts {
@@ -22,7 +24,11 @@ pub fn translate_tx_begin(
             });
         }
         TransactionType::Immediate | TransactionType::Exclusive => {
-            program.emit_insn(Insn::Transaction { db: 0, write: true });
+            program.emit_insn(Insn::Transaction {
+                db: 0,
+                write: true,
+                schema_cookie: schema.schema_version,
+            });
             // TODO: Emit transaction instruction on temporary tables when we support them.
             program.emit_insn(Insn::AutoCommit {
                 auto_commit: false,
diff --git a/core/vdbe/builder.rs b/core/vdbe/builder.rs
index b9abed8ed..a71c01ceb 100644
--- a/core/vdbe/builder.rs
+++ b/core/vdbe/builder.rs
@@ -771,8 +771,13 @@ impl ProgramBuilder {
                 TransactionMode::Read => self.emit_insn(Insn::Transaction {
                     db: 0,
                     write: false,
+                    schema_cookie: 0, // TODO: placeholder until we have epilogue being called only in one place
+                }),
+                TransactionMode::Write => self.emit_insn(Insn::Transaction {
+                    db: 0,
+                    write: true,
+                    schema_cookie: 0, // TODO: placeholder until we have epilogue being called only in one place
                 }),
-                TransactionMode::Write => self.emit_insn(Insn::Transaction { db: 0, write: true }),
                 TransactionMode::None => {}
             }
 
diff --git a/core/vdbe/execute.rs b/core/vdbe/execute.rs
index 56bb30e23..c3bb8d5eb 100644
--- a/core/vdbe/execute.rs
+++ b/core/vdbe/execute.rs
@@ -1989,9 +1989,18 @@ pub fn op_transaction(
     _pager: &Rc<Pager>,
     mv_store: Option<&Arc<MvStore>>,
 ) -> Result<InsnFunctionStepResult> {
-    let Insn::Transaction { db, write } = insn else {
+    let Insn::Transaction {
+        db,
+        write,
+        schema_cookie,
+    } = insn
+    else {
         unreachable!("unexpected Insn {:?}", insn)
     };
+    let header_schema_cookie = header_accessor::get_schema_cookie(pager)?;
+    if header_schema_cookie != *schema_cookie {
+        return Err(LimboError::SchemaUpdated);
+    }
     let conn = program.connection.clone();
     if *write && conn._db.open_flags.contains(OpenFlags::ReadOnly) {
         return Err(LimboError::ReadOnly);
diff --git a/core/vdbe/explain.rs b/core/vdbe/explain.rs
index 0fefedcc2..b891632ae 100644
--- a/core/vdbe/explain.rs
+++ b/core/vdbe/explain.rs
@@ -647,11 +647,11 @@ pub fn insn_to_str(
                 0,
                 "".to_string(),
             ),
-            Insn::Transaction { db, write } => (
+            Insn::Transaction { db, write , schema_cookie} => (
                 "Transaction",
                 *db as i32,
                 *write as i32,
-                0,
+                *schema_cookie as i32,
                 Value::build_text(""),
                 0,
                 format!("iDb={db} write={write}"),
diff --git a/core/vdbe/insn.rs b/core/vdbe/insn.rs
index 6b41d1900..d3a326943 100644
--- a/core/vdbe/insn.rs
+++ b/core/vdbe/insn.rs
@@ -459,8 +459,9 @@ pub enum Insn {
 
     /// Start a transaction.
     Transaction {
-        db: usize,   // p1
-        write: bool, // p2
+        db: usize,          // p1
+        write: bool,        // p2
+        schema_cookie: u32, // p3
     },
 
     /// Set database auto-commit mode and potentially rollback.