Merge 94a1f5a8ea into 057fcb3993

* Remove unreachable code

* Add `indices` field to `MatchBounds`

For matches inside arrays, this field holds the indices of the array
elements that matched. For example, searching for `cat` inside
`{ "a": ["dog", "cat", "fox"] }` would return `indices: [1]`. For nested
arrays, this contains multiple indices, starting with the one for the
top-most array. For matches in fields without arrays, `indices` is not
serialized (does not exist) to save space.

crates/index-scheduler/src/lib.rs

@@ -84,6 +84,8 @@ pub struct Query {
     pub limit: Option<u32>,
     /// The minimum [task id](`meilisearch_types::tasks::Task::uid`) to be matched
     pub from: Option<u32>,
+    /// The order used to return the tasks. By default the newest tasks are returned first and the boolean is `false`.
+    pub reverse: Option<bool>,
     /// The allowed [statuses](`meilisearch_types::tasks::Task::status`) of the matched tasls
     pub statuses: Option<Vec<Status>>,
     /// The allowed [kinds](meilisearch_types::tasks::Kind) of the matched tasks.
@@ -126,6 +128,7 @@ impl Query {
             Query {
                 limit: None,
                 from: None,
+                reverse: None,
                 statuses: None,
                 types: None,
                 index_uids: None,
@@ -706,7 +709,12 @@ impl IndexScheduler {
         let mut tasks = self.all_task_ids(rtxn)?;
 
         if let Some(from) = &query.from {
-            tasks.remove_range(from.saturating_add(1)..);
+            let range = if query.reverse.unwrap_or_default() {
+                u32::MIN..*from
+            } else {
+                from.saturating_add(1)..u32::MAX
+            };
+            tasks.remove_range(range);
         }
 
         if let Some(status) = &query.statuses {
@@ -826,7 +834,11 @@ impl IndexScheduler {
         )?;
 
         if let Some(limit) = query.limit {
-            tasks = tasks.into_iter().rev().take(limit as usize).collect();
+            tasks = if query.reverse.unwrap_or_default() {
+                tasks.into_iter().take(limit as usize).collect()
+            } else {
+                tasks.into_iter().rev().take(limit as usize).collect()
+            };
         }
 
         Ok(tasks)
@@ -951,10 +963,13 @@ impl IndexScheduler {
         let rtxn = self.env.read_txn()?;
 
         let (tasks, total) = self.get_task_ids_from_authorized_indexes(&rtxn, &query, filters)?;
-        let tasks = self.get_existing_tasks(
+        let tasks = if query.reverse.unwrap_or_default() {
-            &rtxn,
+            Box::new(tasks.into_iter()) as Box<dyn Iterator<Item = u32>>
-            tasks.into_iter().rev().take(query.limit.unwrap_or(u32::MAX) as usize),
+        } else {
-        )?;
+            Box::new(tasks.into_iter().rev()) as Box<dyn Iterator<Item = u32>>
+        };
+        let tasks =
+            self.get_existing_tasks(&rtxn, tasks.take(query.limit.unwrap_or(u32::MAX) as usize))?;
 
         let ProcessingTasks { started_at, processing, .. } =
             self.processing_tasks.read().map_err(|_| Error::CorruptedTaskQueue)?.clone();

crates/meilisearch-types/src/error.rs

@@ -318,6 +318,7 @@ InvalidTaskBeforeStartedAt            , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskCanceledBy                 , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskFrom                       , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskLimit                      , InvalidRequest       , BAD_REQUEST ;
+InvalidTaskReverse                    , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskStatuses                   , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskTypes                      , InvalidRequest       , BAD_REQUEST ;
 InvalidTaskUids                       , InvalidRequest       , BAD_REQUEST  ;

crates/meilisearch/src/routes/tasks.rs

@@ -42,6 +42,8 @@ pub struct TasksFilterQuery {
     pub limit: Param<u32>,
     #[deserr(default, error = DeserrQueryParamError<InvalidTaskFrom>)]
     pub from: Option<Param<TaskId>>,
+    #[deserr(default, error = DeserrQueryParamError<InvalidTaskReverse>)]
+    pub reverse: Option<Param<bool>>,
 
     #[deserr(default, error = DeserrQueryParamError<InvalidTaskUids>)]
     pub uids: OptionStarOrList<u32>,
@@ -73,6 +75,7 @@ impl TasksFilterQuery {
         Query {
             limit: Some(self.limit.0),
             from: self.from.as_deref().copied(),
+            reverse: self.reverse.as_deref().copied(),
             statuses: self.statuses.merge_star_and_none(),
             types: self.types.merge_star_and_none(),
             index_uids: self.index_uids.map(|x| x.to_string()).merge_star_and_none(),
@@ -142,6 +145,7 @@ impl TaskDeletionOrCancelationQuery {
         Query {
             limit: None,
             from: None,
+            reverse: None,
             statuses: self.statuses.merge_star_and_none(),
             types: self.types.merge_star_and_none(),
             index_uids: self.index_uids.map(|x| x.to_string()).merge_star_and_none(),
@@ -701,14 +705,14 @@ mod tests {
         {
             let params = "from=12&limit=15&indexUids=toto,tata-78&statuses=succeeded,enqueued&afterEnqueuedAt=2012-04-23&uids=1,2,3";
             let query = deserr_query_params::<TasksFilterQuery>(params).unwrap();
-            snapshot!(format!("{:?}", query), @r###"TasksFilterQuery { limit: Param(15), from: Some(Param(12)), uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: List([Succeeded, Enqueued]), index_uids: List([IndexUid("toto"), IndexUid("tata-78")]), after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }"###);
+            snapshot!(format!("{:?}", query), @r###"TasksFilterQuery { limit: Param(15), from: Some(Param(12)), reverse: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: List([Succeeded, Enqueued]), index_uids: List([IndexUid("toto"), IndexUid("tata-78")]), after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }"###);
         }
         {
             // Stars should translate to `None` in the query
             // Verify value of the default limit
             let params = "indexUids=*&statuses=succeeded,*&afterEnqueuedAt=2012-04-23&uids=1,2,3";
             let query = deserr_query_params::<TasksFilterQuery>(params).unwrap();
-            snapshot!(format!("{:?}", query), @"TasksFilterQuery { limit: Param(20), from: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: Star, index_uids: Star, after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }");
+            snapshot!(format!("{:?}", query), @"TasksFilterQuery { limit: Param(20), from: None, reverse: None, uids: List([1, 2, 3]), canceled_by: None, types: None, statuses: Star, index_uids: Star, after_enqueued_at: Other(2012-04-24 0:00:00.0 +00:00:00), before_enqueued_at: None, after_started_at: None, before_started_at: None, after_finished_at: None, before_finished_at: None }");
         }
         {
             // Stars should also translate to `None` in task deletion/cancelation queries

crates/meilisearch/src/search/mod.rs

@@ -1733,7 +1733,10 @@ fn format_fields(
     // select the attributes to retrieve
     let displayable_names =
         displayable_ids.iter().map(|&fid| field_ids_map.name(fid).expect("Missing field name"));
-    permissive_json_pointer::map_leaf_values(&mut document, displayable_names, |key, value| {
+    permissive_json_pointer::map_leaf_values(
+        &mut document,
+        displayable_names,
+        |key, array_indices, value| {
             // To get the formatting option of each key we need to see all the rules that applies
             // to the value and merge them together. eg. If a user said he wanted to highlight `doggo`
             // and crop `doggo.name`. `doggo.name` needs to be highlighted + cropped while `doggo.age` is only
@@ -1764,6 +1767,7 @@ fn format_fields(
                 format,
                 &mut infos,
                 compute_matches,
+                array_indices,
                 locales,
             );
 
@@ -1772,7 +1776,8 @@ fn format_fields(
                     matches.insert(key.to_owned(), infos);
                 }
             }
-    });
+        },
+    );
 
     let selectors = formatted_options
         .keys()
@@ -1790,13 +1795,14 @@ fn format_value(
     format_options: Option<FormatOptions>,
     infos: &mut Vec<MatchBounds>,
     compute_matches: bool,
+    array_indices: &[usize],
     locales: Option<&[Language]>,
 ) -> Value {
     match value {
         Value::String(old_string) => {
             let mut matcher = builder.build(&old_string, locales);
             if compute_matches {
-                let matches = matcher.matches();
+                let matches = matcher.matches(array_indices);
                 infos.extend_from_slice(&matches[..]);
             }
 
@@ -1808,51 +1814,15 @@ fn format_value(
                 None => Value::String(old_string),
             }
         }
-        Value::Array(values) => Value::Array(
+        // `map_leaf_values` makes sure this is only called for leaf fields
-            values
+        Value::Array(_) => unreachable!(),
-                .into_iter()
+        Value::Object(_) => unreachable!(),
-                .map(|v| {
-                    format_value(
-                        v,
-                        builder,
-                        format_options.map(|format_options| FormatOptions {
-                            highlight: format_options.highlight,
-                            crop: None,
-                        }),
-                        infos,
-                        compute_matches,
-                        locales,
-                    )
-                })
-                .collect(),
-        ),
-        Value::Object(object) => Value::Object(
-            object
-                .into_iter()
-                .map(|(k, v)| {
-                    (
-                        k,
-                        format_value(
-                            v,
-                            builder,
-                            format_options.map(|format_options| FormatOptions {
-                                highlight: format_options.highlight,
-                                crop: None,
-                            }),
-                            infos,
-                            compute_matches,
-                            locales,
-                        ),
-                    )
-                })
-                .collect(),
-        ),
         Value::Number(number) => {
             let s = number.to_string();
 
             let mut matcher = builder.build(&s, locales);
             if compute_matches {
-                let matches = matcher.matches();
+                let matches = matcher.matches(array_indices);
                 infos.extend_from_slice(&matches[..]);
             }
 

crates/meilisearch/tests/search/formatted.rs

@@ -208,7 +208,10 @@ async fn format_nested() {
                         "doggos.name": [
                           {
                             "start": 0,
-                            "length": 5
+                            "length": 5,
+                            "indices": [
+                              0
+                            ]
                           }
                         ]
                       }

crates/meilisearch/tests/tasks/errors.rs

@@ -279,6 +279,55 @@ async fn task_bad_from() {
     "###);
 }
 
+#[actix_rt::test]
+async fn task_bad_reverse() {
+    let server = Server::new_shared();
+
+    let (response, code) = server.tasks_filter("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Invalid value in parameter `reverse`: could not parse `doggo` as a boolean, expected either `true` or `false`",
+      "code": "invalid_task_reverse",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_task_reverse"
+    }
+    "###);
+
+    let (response, code) = server.tasks_filter("reverse=*").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Invalid value in parameter `reverse`: could not parse `*` as a boolean, expected either `true` or `false`",
+      "code": "invalid_task_reverse",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#invalid_task_reverse"
+    }
+    "###);
+
+    let (response, code) = server.cancel_tasks("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Unknown parameter `reverse`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
+      "code": "bad_request",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#bad_request"
+    }
+    "###);
+
+    let (response, code) = server.delete_tasks("reverse=doggo").await;
+    snapshot!(code, @"400 Bad Request");
+    snapshot!(response, @r###"
+    {
+      "message": "Unknown parameter `reverse`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
+      "code": "bad_request",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#bad_request"
+    }
+    "###);
+}
+
 #[actix_rt::test]
 async fn task_bad_after_enqueued_at() {
     let server = Server::new_shared();

crates/meilisearch/tests/tasks/mod.rs

@@ -62,6 +62,44 @@ async fn list_tasks() {
     assert_eq!(response["results"].as_array().unwrap().len(), 2);
 }
 
+#[actix_rt::test]
+async fn list_tasks_pagination_and_reverse() {
+    let server = Server::new().await;
+    // First of all we want to create a lot of tasks very quickly. The fastest way is to delete a lot of unexisting indexes
+    let mut last_task = None;
+    for i in 0..10 {
+        let index = server.index(format!("test-{i}"));
+        last_task = Some(index.create(None).await.0.uid());
+    }
+    server.wait_task(last_task.unwrap()).await;
+
+    let (response, code) = server.tasks_filter("limit=3").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[9, 8, 7]");
+
+    let (response, code) = server.tasks_filter("limit=3&from=1").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[1, 0]");
+
+    // In reversed order
+
+    let (response, code) = server.tasks_filter("limit=3&reverse=true").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[0, 1, 2]");
+
+    let (response, code) = server.tasks_filter("limit=3&from=8&reverse=true").await;
+    assert_eq!(code, 200);
+    let results = response["results"].as_array().unwrap();
+    let task_ids: Vec<_> = results.iter().map(|ret| ret["uid"].as_u64().unwrap()).collect();
+    snapshot!(format!("{task_ids:?}"), @"[8, 9]");
+}
+
 #[actix_rt::test]
 async fn list_tasks_with_star_filters() {
     let server = Server::new().await;
@@ -193,131 +231,6 @@ async fn list_tasks_status_and_type_filtered() {
     assert_eq!(response["results"].as_array().unwrap().len(), 2);
 }
 
-#[actix_rt::test]
-async fn get_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.tasks_filter("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `limit`, `from`, `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("from=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `from`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_from",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_from"
-    }
-    "###);
-
-    let (response, code) = server.tasks_filter("beforeStartedAt=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `beforeStartedAt`: `pied` is an invalid date-time. It should follow the YYYY-MM-DD or RFC 3339 date-time format.",
-      "code": "invalid_task_before_started_at",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_before_started_at"
-    }
-    "###);
-}
-
-#[actix_rt::test]
-async fn delete_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.delete_tasks("").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Query parameters to filter the tasks to delete are missing. Available query parameters are: `uids`, `indexUids`, `statuses`, `types`, `canceledBy`, `beforeEnqueuedAt`, `afterEnqueuedAt`, `beforeStartedAt`, `afterStartedAt`, `beforeFinishedAt`, `afterFinishedAt`.",
-      "code": "missing_task_filters",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#missing_task_filters"
-    }
-    "###);
-
-    let (response, code) = server.delete_tasks("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.delete_tasks("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-}
-
-#[actix_rt::test]
-async fn cancel_task_filter_error() {
-    let server = Server::new().await;
-
-    let (response, code) = server.cancel_tasks("").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Query parameters to filter the tasks to cancel are missing. Available query parameters are: `uids`, `indexUids`, `statuses`, `types`, `canceledBy`, `beforeEnqueuedAt`, `afterEnqueuedAt`, `beforeStartedAt`, `afterStartedAt`, `beforeFinishedAt`, `afterFinishedAt`.",
-      "code": "missing_task_filters",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#missing_task_filters"
-    }
-    "###);
-
-    let (response, code) = server.cancel_tasks("lol=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Unknown parameter `lol`: expected one of `uids`, `canceledBy`, `types`, `statuses`, `indexUids`, `afterEnqueuedAt`, `beforeEnqueuedAt`, `afterStartedAt`, `beforeStartedAt`, `afterFinishedAt`, `beforeFinishedAt`",
-      "code": "bad_request",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#bad_request"
-    }
-    "###);
-
-    let (response, code) = server.cancel_tasks("uids=pied").await;
-    assert_eq!(code, 400, "{}", response);
-    meili_snap::snapshot!(meili_snap::json_string!(response), @r###"
-    {
-      "message": "Invalid value in parameter `uids`: could not parse `pied` as a positive integer",
-      "code": "invalid_task_uids",
-      "type": "invalid_request",
-      "link": "https://docs.meilisearch.com/errors#invalid_task_uids"
-    }
-    "###);
-}
-
 macro_rules! assert_valid_summarized_task {
     ($response:expr, $task_type:literal, $index:literal) => {{
         assert_eq!($response.as_object().unwrap().len(), 5);

crates/milli/src/search/new/matches/mod.rs

@@ -105,6 +105,8 @@ impl FormatOptions {
 pub struct MatchBounds {
     pub start: usize,
     pub length: usize,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub indices: Option<Vec<usize>>,
 }
 
 /// Structure used to analyze a string, compute words that match,
@@ -220,15 +222,20 @@ impl<'t, 'tokenizer> Matcher<'t, 'tokenizer, '_, '_> {
     }
 
     /// Returns boundaries of the words that match the query.
-    pub fn matches(&mut self) -> Vec<MatchBounds> {
+    pub fn matches(&mut self, array_indices: &[usize]) -> Vec<MatchBounds> {
         match &self.matches {
-            None => self.compute_matches().matches(),
+            None => self.compute_matches().matches(array_indices),
             Some((tokens, matches)) => matches
                 .iter()
                 .map(|m| MatchBounds {
                     start: tokens[m.get_first_token_pos()].byte_start,
                     // TODO: Why is this in chars, while start is in bytes?
                     length: m.char_count,
+                    indices: if array_indices.is_empty() {
+                        None
+                    } else {
+                        Some(array_indices.to_owned())
+                    },
                 })
                 .collect(),
         }

crates/permissive-json-pointer/src/lib.rs

@@ -45,7 +45,7 @@ fn contained_in(selector: &str, key: &str) -> bool {
 /// map_leaf_values(
 ///     value.as_object_mut().unwrap(),
 ///     ["jean.race.name"],
-///     |key, value| match (value, key) {
+///     |key, _array_indices, value| match (value, key) {
 ///         (Value::String(name), "jean.race.name") => *name = "patou".to_string(),
 ///         _ => unreachable!(),
 ///     },
@@ -66,17 +66,18 @@ fn contained_in(selector: &str, key: &str) -> bool {
 pub fn map_leaf_values<'a>(
     value: &mut Map<String, Value>,
     selectors: impl IntoIterator<Item = &'a str>,
-    mut mapper: impl FnMut(&str, &mut Value),
+    mut mapper: impl FnMut(&str, &[usize], &mut Value),
 ) {
     let selectors: Vec<_> = selectors.into_iter().collect();
-    map_leaf_values_in_object(value, &selectors, "", &mut mapper);
+    map_leaf_values_in_object(value, &selectors, "", &[], &mut mapper);
 }
 
 pub fn map_leaf_values_in_object(
     value: &mut Map<String, Value>,
     selectors: &[&str],
     base_key: &str,
-    mapper: &mut impl FnMut(&str, &mut Value),
+    array_indices: &[usize],
+    mapper: &mut impl FnMut(&str, &[usize], &mut Value),
 ) {
     for (key, value) in value.iter_mut() {
         let base_key = if base_key.is_empty() {
@@ -94,12 +95,12 @@ pub fn map_leaf_values_in_object(
         if should_continue {
             match value {
                 Value::Object(object) => {
-                    map_leaf_values_in_object(object, selectors, &base_key, mapper)
+                    map_leaf_values_in_object(object, selectors, &base_key, array_indices, mapper)
                 }
                 Value::Array(array) => {
-                    map_leaf_values_in_array(array, selectors, &base_key, mapper)
+                    map_leaf_values_in_array(array, selectors, &base_key, array_indices, mapper)
                 }
-                value => mapper(&base_key, value),
+                value => mapper(&base_key, array_indices, value),
             }
         }
     }
@@ -109,13 +110,24 @@ pub fn map_leaf_values_in_array(
     values: &mut [Value],
     selectors: &[&str],
     base_key: &str,
-    mapper: &mut impl FnMut(&str, &mut Value),
+    base_array_indices: &[usize],
+    mapper: &mut impl FnMut(&str, &[usize], &mut Value),
 ) {
-    for value in values.iter_mut() {
+    // This avoids allocating twice
+    let mut array_indices = Vec::with_capacity(base_array_indices.len() + 1);
+    array_indices.extend_from_slice(base_array_indices);
+    array_indices.push(0);
+
+    for (i, value) in values.iter_mut().enumerate() {
+        *array_indices.last_mut().unwrap() = i;
         match value {
-            Value::Object(object) => map_leaf_values_in_object(object, selectors, base_key, mapper),
+            Value::Object(object) => {
-            Value::Array(array) => map_leaf_values_in_array(array, selectors, base_key, mapper),
+                map_leaf_values_in_object(object, selectors, base_key, &array_indices, mapper)
-            value => mapper(base_key, value),
+            }
+            Value::Array(array) => {
+                map_leaf_values_in_array(array, selectors, base_key, &array_indices, mapper)
+            }
+            value => mapper(base_key, &array_indices, value),
         }
     }
 }
@@ -743,12 +755,14 @@ mod tests {
             }
         });
 
-        map_leaf_values(value.as_object_mut().unwrap(), ["jean.race.name"], |key, value| {
+        map_leaf_values(
-            match (value, key) {
+            value.as_object_mut().unwrap(),
+            ["jean.race.name"],
+            |key, _, value| match (value, key) {
                 (Value::String(name), "jean.race.name") => *name = S("patou"),
                 _ => unreachable!(),
-            }
+            },
-        });
+        );
 
         assert_eq!(
             value,
@@ -775,7 +789,7 @@ mod tests {
         });
 
         let mut calls = 0;
-        map_leaf_values(value.as_object_mut().unwrap(), ["jean"], |key, value| {
+        map_leaf_values(value.as_object_mut().unwrap(), ["jean"], |key, _, value| {
             calls += 1;
             match (value, key) {
                 (Value::String(name), "jean.race.name") => *name = S("patou"),
@@ -798,4 +812,52 @@ mod tests {
             })
         );
     }
+
+    #[test]
+    fn map_array() {
+        let mut value: Value = json!({
+            "no_array": "peter",
+            "simple": ["foo", "bar"],
+            "nested": [
+                {
+                    "a": [
+                        ["cat", "dog"],
+                        ["fox", "bear"],
+                    ],
+                    "b": "hi",
+                },
+                {
+                    "a": ["green", "blue"],
+                },
+            ],
+        });
+
+        map_leaf_values(
+            value.as_object_mut().unwrap(),
+            ["no_array", "simple", "nested"],
+            |_key, array_indices, value| {
+                *value = format!("{array_indices:?}").into();
+            },
+        );
+
+        assert_eq!(
+            value,
+            json!({
+                "no_array": "[]",
+                "simple": ["[0]", "[1]"],
+                "nested": [
+                    {
+                        "a": [
+                            ["[0, 0, 0]", "[0, 0, 1]"],
+                            ["[0, 1, 0]", "[0, 1, 1]"],
+                        ],
+                        "b": "[0]",
+                    },
+                    {
+                        "a": ["[1, 0]", "[1, 1]"],
+                    },
+                ],
+            })
+        );
+    }
 }