Add a NoOp operation in index update

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

@@ -28,7 +28,11 @@ pub fn upgrade_index_scheduler(
     let current_minor = to.1;
     let current_patch = to.2;
 
-    let upgrade_functions: &[&dyn UpgradeIndexScheduler] = &[&ToCurrentNoOp {}];
+    let upgrade_functions: &[&dyn UpgradeIndexScheduler] = &[
+        // This is the last upgrade function, it will be called when the index is up to date.
+        // any other upgrade function should be added before this one.
+        &ToCurrentNoOp {},
+    ];
 
     let start = match from {
         (1, 12, _) => 0,

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

@@ -8,6 +8,7 @@ use v1_13::{V1_13_0_To_V1_13_1, V1_13_1_To_Latest_V1_13};
 use v1_14::Latest_V1_13_To_Latest_V1_14;
 use v1_15::Latest_V1_14_To_Latest_V1_15;
 
+use crate::constants::{VERSION_MAJOR, VERSION_MINOR, VERSION_PATCH};
 use crate::progress::{Progress, VariableNameStep};
 use crate::{Index, InternalError, Result};
 
@@ -42,6 +43,9 @@ where
         &V1_13_1_To_Latest_V1_13 {},
         &Latest_V1_13_To_Latest_V1_14 {},
         &Latest_V1_14_To_Latest_V1_15 {},
+        // This is the last upgrade function, it will be called when the index is up to date.
+        // any other upgrade function should be added before this one.
+        &ToCurrentNoOp {},
     ];
 
     let start = match from {
@@ -51,7 +55,7 @@ where
         (1, 13, _) => 4,
         (1, 14, _) => 5,
         // We must handle the current version in the match because in case of a failure some index may have been upgraded but not other.
-        (1, 15, _) => 5,
+        (1, 15, _) => 6,
         (major, minor, patch) => {
             return Err(InternalError::CannotUpgradeToVersion(major, minor, patch).into())
         }
@@ -87,3 +91,22 @@ where
 
     Ok(regenerate_stats)
 }
+
+#[allow(non_camel_case_types)]
+struct ToCurrentNoOp {}
+
+impl UpgradeIndex for ToCurrentNoOp {
+    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, VERSION_MINOR, VERSION_PATCH)
+    }
+}