Build in migration rejection

Author: macalinao

programs/migrator/src/account_contexts.rs

@@ -95,6 +95,16 @@ pub struct ApproveMigration<'info> {
     pub approver: Signer<'info>,
 }
 
+#[derive(Accounts)]
+pub struct RejectMigration<'info> {
+    /// The migrator.
+    pub migrator: Account<'info, Migrator>,
+    /// The migration.
+    pub migration: Account<'info, Migration>,
+    /// [Migrator::approver].
+    pub approver: Signer<'info>,
+}
+
 #[derive(Accounts)]
 #[instruction(bump: u8, title: String, description: String)]
 pub struct ProposeMigration<'info> {

programs/migrator/src/account_validators.rs

@@ -6,7 +6,7 @@ use solana_program::{
 use vipers::{assert_keys, invariant, program_err, unwrap_opt, validate::Validate};
 
 use crate::{
-    account_contexts::{NewMigrator, ReserveProgramID},
+    account_contexts::{NewMigrator, RejectMigration, ReserveProgramID},
     bpf_loader_upgradeable::UpgradeableLoaderAccount,
     ApproveMigration, ApprovedMigration, DeployProgram, LiveProgram, ProposeMigration,
     UndeployedProgram, UpgradeProgram,
@@ -79,6 +79,22 @@ impl<'info> Validate<'info> for ApproveMigration<'info> {
             "migration.migrator"
         );
         assert_keys!(self.migrator.approver, self.approver, "migrator.approver");
+        require!(self.migration.executed_at == -1, MigrationAlreadyExecuted);
+
+        Ok(())
+    }
+}
+
+impl<'info> Validate<'info> for RejectMigration<'info> {
+    fn validate(&self) -> ProgramResult {
+        assert_keys!(
+            self.migration.migrator,
+            self.migration,
+            "migration.migrator"
+        );
+        assert_keys!(self.migrator.approver, self.approver, "migrator.approver");
+        require!(self.migration.executed_at == -1, MigrationAlreadyExecuted);
+
         Ok(())
     }
 }

programs/migrator/src/instructions/approver.rs

@@ -129,9 +129,30 @@ pub fn approve_migration(ctx: Context<ApproveMigration>, deadline: i64) -> Progr
         deadline > Clock::get()?.unix_timestamp,
         ExpiryMustBeInFuture
     );
+
+    // un-reject if the migration was rejected.
+    let migration = &mut ctx.accounts.migration;
+    if migration.rejected_at != -1 {
+        migration.rejected_at = -1;
+    }
+
     let migrator = &mut ctx.accounts.migrator;
-    migrator.approver = ctx.accounts.approver.key();
     migrator.pending_migration = ctx.accounts.migration.key();
     migrator.approval_expires_at = deadline;
     Ok(())
 }
+
+/// Rejects the current [Migration].
+pub fn reject_migration(ctx: Context<RejectMigration>) -> ProgramResult {
+    let migration = &mut ctx.accounts.migration;
+    migration.rejected_at = Clock::get()?.unix_timestamp;
+
+    // cancel migration if it's the pending one
+    let migrator = &mut ctx.accounts.migrator;
+    if migrator.pending_migration.key() == migration.key() {
+        migrator.pending_migration = Pubkey::default();
+        migrator.approval_expires_at = -1;
+    }
+
+    Ok(())
+}

programs/migrator/src/lib.rs

@@ -53,6 +53,11 @@ pub mod migrator {
         ctx.accounts.validate()?;
         instructions::approver::approve_migration(ctx, deadline)
     }
+    /// Approves a [Migration].
+    pub fn reject_migration(ctx: Context<RejectMigration>) -> ProgramResult {
+        ctx.accounts.validate()?;
+        instructions::approver::reject_migration(ctx)
+    }
 
     //////////////////////////////////////////
     // Public instructions