introduce a trait to upgrade the indexes

crates/index-scheduler/src/scheduler/process_batch.rs

@@ -316,7 +316,10 @@ impl IndexScheduler {
                 Ok(vec![task])
             }
             Batch::UpgradeDatabase { mut tasks } => {
-                let ret = catch_unwind(AssertUnwindSafe(|| self.process_upgrade(progress)));
+                let KindWithContent::UpgradeDatabase { from } = tasks.last().unwrap().kind else {
+                    unreachable!();
+                };
+                let ret = catch_unwind(AssertUnwindSafe(|| self.process_upgrade(from, progress)));
                 match ret {
                     Ok(Ok(())) => (),
                     Ok(Err(e)) => return Err(Error::DatabaseUpgrade(Box::new(e))),

crates/index-scheduler/src/scheduler/process_upgrade/mod.rs

@@ -4,7 +4,11 @@ use meilisearch_types::milli::progress::{Progress, VariableNameStep};
 use crate::{Error, IndexScheduler, Result};
 
 impl IndexScheduler {
-    pub(super) fn process_upgrade(&self, progress: Progress) -> Result<()> {
+    pub(super) fn process_upgrade(
+        &self,
+        db_version: (u32, u32, u32),
+        progress: Progress,
+    ) -> Result<()> {
         #[cfg(test)]
         self.maybe_fail(crate::test_utils::FailureLocation::ProcessUpgrade)?;
 
@@ -19,9 +23,13 @@ impl IndexScheduler {
             ));
             let index = self.index(uid)?;
             let mut index_wtxn = index.write_txn()?;
-            let regen_stats =
-                milli::update::upgrade::upgrade(&mut index_wtxn, &index, progress.clone())
-                    .map_err(|e| Error::from_milli(e, Some(uid.to_string())))?;
+            let regen_stats = milli::update::upgrade::upgrade(
+                &mut index_wtxn,
+                &index,
+                db_version,
+                progress.clone(),
+            )
+            .map_err(|e| Error::from_milli(e, Some(uid.to_string())))?;
             if regen_stats {
                 let stats = crate::index_mapper::IndexStats::new(&index, &index_wtxn)
                     .map_err(|e| Error::from_milli(e, Some(uid.to_string())))?;

crates/milli/src/update/upgrade/mod.rs

@@ -1,32 +1,39 @@
 mod v1_12;
 
 use heed::RwTxn;
-use v1_12::{v1_12_3_to_v1_13, v1_12_to_v1_12_3};
+use v1_12::{V1_12_3_To_Current, V1_12_To_V1_12_3};
 
 use crate::progress::{Progress, VariableNameStep};
 use crate::{Index, InternalError, Result};
 
+trait UpgradeIndex {
+    /// Returns true if the index scheduler must regenerate its cached stats
+    fn upgrade(
+        &self,
+        wtxn: &mut RwTxn,
+        index: &Index,
+        original: (u32, u32, u32),
+        progress: Progress,
+    ) -> Result<bool>;
+    fn target_version(&self) -> (u32, u32, u32);
+}
+
 /// Return true if the cached stats of the index must be regenerated
-pub fn upgrade(wtxn: &mut RwTxn, index: &Index, progress: Progress) -> Result<bool> {
-    let from = index.get_version(wtxn)?;
-    let upgrade_functions = [
-        (
-            v1_12_to_v1_12_3 as fn(&mut RwTxn, &Index, Progress) -> Result<bool>,
-            "Upgrading from v1.12.(0/1/2) to v1.12.3",
-        ),
-        (
-            v1_12_3_to_v1_13 as fn(&mut RwTxn, &Index, Progress) -> Result<bool>,
-            "Upgrading from v1.12.3+ to v1.13",
-        ),
-    ];
+pub fn upgrade(
+    wtxn: &mut RwTxn,
+    index: &Index,
+    db_version: (u32, u32, u32),
+    progress: Progress,
+) -> Result<bool> {
+    let from = index.get_version(wtxn)?.unwrap_or(db_version);
+    let upgrade_functions: &[&dyn UpgradeIndex] = &[&V1_12_To_V1_12_3 {}, &V1_12_3_To_Current()];
 
     let start = match from {
-        // If there was no version it means we're coming from the v1.12
-        None | Some((1, 12, 0..=2)) => 0,
-        Some((1, 12, 3..)) => 1,
+        (1, 12, 0..=2) => 0,
+        (1, 12, 3..) => 1,
         // We must handle the current version in the match because in case of a failure some index may have been upgraded but not other.
-        Some((1, 13, _)) => return Ok(false),
-        Some((major, minor, patch)) => {
+        (1, 13, _) => return Ok(false),
+        (major, minor, patch) => {
             return Err(InternalError::CannotUpgradeToVersion(major, minor, patch).into())
         }
     };
@@ -34,14 +41,26 @@ pub fn upgrade(wtxn: &mut RwTxn, index: &Index, progress: Progress) -> Result<bo
     enum UpgradeVersion {}
     let upgrade_path = &upgrade_functions[start..];
 
+    let mut current_version = from;
+
     let mut regenerate_stats = false;
-    for (i, (upgrade_function, upgrade_msg)) in upgrade_path.iter().enumerate() {
+    for (i, upgrade) in upgrade_path.iter().enumerate() {
+        let target = upgrade.target_version();
         progress.update_progress(VariableNameStep::<UpgradeVersion>::new(
-            upgrade_msg.to_string(),
+            format!(
+                "Upgrading from v{}.{}.{} to v{}.{}.{}",
+                current_version.0,
+                current_version.1,
+                current_version.2,
+                target.0,
+                target.1,
+                target.2
+            ),
             i as u32,
             upgrade_path.len() as u32,
         ));
-        regenerate_stats |= (upgrade_function)(wtxn, index, progress.clone())?;
+        regenerate_stats |= upgrade.upgrade(wtxn, index, from, progress.clone())?;
+        current_version = target;
     }
 
     Ok(regenerate_stats)

crates/milli/src/update/upgrade/v1_12.rs

@@ -1,28 +1,56 @@
 use heed::RwTxn;
 
+use crate::constants::{VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH};
 use crate::progress::Progress;
 use crate::{make_enum_progress, Index, Result};
 
-// The field distribution was not computed correctly in the v1.12 until the v1.12.3
-pub(super) fn v1_12_to_v1_12_3(
-    wtxn: &mut RwTxn,
-    index: &Index,
-    progress: Progress,
-) -> Result<bool> {
-    make_enum_progress! {
-        enum FieldDistribution {
-            RebuildingFieldDistribution,
-        }
-    };
-    progress.update_progress(FieldDistribution::RebuildingFieldDistribution);
-    crate::update::new::reindex::field_distribution(index, wtxn, &progress)?;
-    Ok(true)
+use super::UpgradeIndex;
+
+#[allow(non_camel_case_types)]
+pub(super) struct V1_12_To_V1_12_3 {}
+
+impl UpgradeIndex for V1_12_To_V1_12_3 {
+    fn upgrade(
+        &self,
+        wtxn: &mut RwTxn,
+        index: &Index,
+        _original: (u32, u32, u32),
+        progress: Progress,
+    ) -> Result<bool> {
+        make_enum_progress! {
+            enum FieldDistribution {
+                RebuildingFieldDistribution,
+            }
+        };
+        progress.update_progress(FieldDistribution::RebuildingFieldDistribution);
+        crate::update::new::reindex::field_distribution(index, wtxn, &progress)?;
+        Ok(true)
+    }
+
+    fn target_version(&self) -> (u32, u32, u32) {
+        (1, 12, 3)
+    }
 }
 
-pub(super) fn v1_12_3_to_v1_13(
-    _wtxn: &mut RwTxn,
-    _index: &Index,
-    _progress: Progress,
-) -> Result<bool> {
-    Ok(false)
+#[allow(non_camel_case_types)]
+pub(super) struct V1_12_3_To_Current();
+
+impl UpgradeIndex for V1_12_3_To_Current {
+    fn upgrade(
+        &self,
+        _wtxn: &mut RwTxn,
+        _index: &Index,
+        _original: (u32, u32, u32),
+        _progress: Progress,
+    ) -> Result<bool> {
+        Ok(false)
+    }
+
+    fn target_version(&self) -> (u32, u32, u32) {
+        (
+            VERSION_MAJOR.parse().unwrap(),
+            VERSION_MINOR.parse().unwrap(),
+            VERSION_PATCH.parse().unwrap(),
+        )
+    }
 }