From 34d8c1a903dc7f926291118c5286f399ffdc9f57 Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Mon, 20 Jan 2025 10:32:20 +0100
Subject: [PATCH] Make offline upgrade more flexible

---
 crates/meilitool/src/upgrade/mod.rs | 49 +++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 3 deletions(-)

diff --git a/crates/meilitool/src/upgrade/mod.rs b/crates/meilitool/src/upgrade/mod.rs
index 47ca2cbd9..51cb5f454 100644
--- a/crates/meilitool/src/upgrade/mod.rs
+++ b/crates/meilitool/src/upgrade/mod.rs
@@ -20,6 +20,34 @@ pub struct OfflineUpgrade {
 
 impl OfflineUpgrade {
     pub fn upgrade(self) -> anyhow::Result<()> {
+        // Adding a version?
+        //
+        // 1. Update the LAST_SUPPORTED_UPGRADE_FROM_VERSION and LAST_SUPPORTED_UPGRADE_TO_VERSION.
+        // 2. Add new version to the upgrade list if necessary
+        // 3. Use `no_upgrade` as index for versions that are compatible.
+
+        if self.current_version == self.target_version {
+            println!("Database is already at the target version. Exiting.");
+            return Ok(());
+        }
+
+        if self.current_version > self.target_version {
+            bail!(
+                "Cannot downgrade from {}.{}.{} to {}.{}.{}. Downgrade not supported",
+                self.current_version.0,
+                self.current_version.1,
+                self.current_version.2,
+                self.target_version.0,
+                self.target_version.1,
+                self.target_version.2
+            );
+        }
+
+        const FIRST_SUPPORTED_UPGRADE_FROM_VERSION: &str = "1.9.0";
+        const LAST_SUPPORTED_UPGRADE_FROM_VERSION: &str = "1.12.5";
+        const FIRST_SUPPORTED_UPGRADE_TO_VERSION: &str = "1.10.0";
+        const LAST_SUPPORTED_UPGRADE_TO_VERSION: &str = "1.12.5";
+
         let upgrade_list = [
             (
                 v1_9_to_v1_10 as fn(&Path, &str, &str, &str) -> Result<(), anyhow::Error>,
@@ -32,6 +60,8 @@ impl OfflineUpgrade {
             (v1_12_to_v1_12_3, "1", "12", "3"),
         ];
 
+        let no_upgrade: usize = upgrade_list.len();
+
         let (current_major, current_minor, current_patch) = &self.current_version;
 
         let start_at = match (
@@ -43,8 +73,11 @@ impl OfflineUpgrade {
             ("1", "10", _) => 1,
             ("1", "11", _) => 2,
             ("1", "12", x) if x == "0" || x == "1" || x == "2" => 3,
+            ("1", "12", x) if x == "3" || x == "4" || x == "5" => no_upgrade,
             _ => {
-                bail!("Unsupported current version {current_major}.{current_minor}.{current_patch}. Can only upgrade from v1.9 and v1.10")
+                bail!("Unsupported current version {current_major}.{current_minor}.{current_patch}. Can only upgrade from versions in range [{}-{}]",
+                      FIRST_SUPPORTED_UPGRADE_FROM_VERSION,
+                      LAST_SUPPORTED_UPGRADE_FROM_VERSION);
             }
         };
 
@@ -54,17 +87,27 @@ impl OfflineUpgrade {
             ("1", "10", _) => 0,
             ("1", "11", _) => 1,
             ("1", "12", x) if x == "0" || x == "1" || x == "2" => 2,
-            ("1", "12", "3") => 3,
+            ("1", "12", x) if x == "3" || x == "4" || x == "5" => 3,
             (major, _, _) if major.starts_with('v') => {
                 bail!("Target version must not starts with a `v`. Instead of writing `v1.9.0` write `1.9.0` for example.")
             }
             _ => {
-                bail!("Unsupported target version {target_major}.{target_minor}.{target_patch}. Can only upgrade to v1.10 and v1.11")
+                bail!("Unsupported target version {target_major}.{target_minor}.{target_patch}. Can only upgrade to versions in range [{}-{}]",
+                      FIRST_SUPPORTED_UPGRADE_TO_VERSION,
+                      LAST_SUPPORTED_UPGRADE_TO_VERSION);
             }
         };
 
         println!("Starting the upgrade from {current_major}.{current_minor}.{current_patch} to {target_major}.{target_minor}.{target_patch}");
 
+        if start_at == no_upgrade {
+            println!("No upgrade operation to perform, writing VERSION file");
+            create_version_file(&self.db_path, target_major, target_minor, target_patch)
+                .context("while writing VERSION file after the upgrade")?;
+            println!("Success");
+            return Ok(());
+        }
+
         #[allow(clippy::needless_range_loop)]
         for index in start_at..=ends_at {
             let (func, major, minor, patch) = upgrade_list[index];