Issue #117: Handle groups rows elemenations in case group by don't cr…

…eate extra groups

crates/gitql-engine/src/engine.rs

@@ -77,6 +77,7 @@ fn evaluate_select_query(
     let hidden_selections_map = query.hidden_selections;
     let hidden_selections = hidden_selections_map.values().flatten().cloned().collect();
     let mut statements_map = query.statements;
+    let has_group_by_statement = statements_map.contains_key("group");
 
     for gql_command in FIXED_LOGICAL_PLAN {
         if statements_map.contains_key(gql_command) {
@@ -96,6 +97,7 @@ fn evaluate_select_query(
                         &mut gitql_object,
                         &mut alias_table,
                         &hidden_selections_map,
+                        has_group_by_statement,
                     )?;
 
                     // If the main group is empty, no need to perform other statements
@@ -121,19 +123,21 @@ fn evaluate_select_query(
                         &mut gitql_object,
                         &mut alias_table,
                         &hidden_selections_map,
+                        has_group_by_statement,
                     )?;
                 }
             }
         }
     }
 
     // Remove Hidden Selection from the rows after executing the query plan
+    let number_of_groups = gitql_object.groups.len();
     let group: &mut Group = &mut gitql_object.groups[0];
     remove_hidden_selected(&mut gitql_object.titles, group, &hidden_selections);
 
     // If there are many groups that mean group by is executed before.
     // must merge each group into only one element
-    if gitql_object.len() > 1 {
+    if number_of_groups > 1 {
         for group in gitql_object.groups.iter_mut() {
             if group.len() > 1 {
                 group.rows.drain(1..);
@@ -142,14 +146,12 @@ fn evaluate_select_query(
     }
     // If it a single group but it select only aggregations function,
     // should return only first element in the group
-    else if gitql_object.len() == 1
+    else if number_of_groups == 1
         && !query.has_group_by_statement
         && query.has_aggregation_function
+        && group.len() > 1
     {
-        let group: &mut Group = &mut gitql_object.groups[0];
-        if group.len() > 1 {
-            group.rows.drain(1..);
-        }
+        group.rows.drain(1..);
     }
 
     // Into statement must be executed last after flatted and remove hidden selections
@@ -162,6 +164,7 @@ fn evaluate_select_query(
             &mut gitql_object,
             &mut alias_table,
             &hidden_selections_map,
+            has_group_by_statement,
         )?;
 
         return Ok(EvaluationResult::SelectedInfo);

crates/gitql-engine/src/engine_executor.rs

@@ -44,6 +44,7 @@ pub fn execute_statement(
     gitql_object: &mut GitQLObject,
     alias_table: &mut HashMap<String, String>,
     hidden_selection: &HashMap<String, Vec<String>>,
+    has_group_by_statement: bool,
 ) -> Result<(), String> {
     match statement.kind() {
         Do => {
@@ -106,7 +107,13 @@ pub fn execute_statement(
                 .as_any()
                 .downcast_ref::<AggregationsStatement>()
                 .unwrap();
-            execute_aggregation_function_statement(env, statement, gitql_object, alias_table)
+            execute_aggregation_function_statement(
+                env,
+                statement,
+                gitql_object,
+                alias_table,
+                has_group_by_statement,
+            )
         }
         Into => {
             let statement = statement.as_any().downcast_ref::<IntoStatement>().unwrap();
@@ -450,13 +457,13 @@ fn execute_group_by_statement(
             e.insert(next_group_index);
             next_group_index += 1;
             gitql_object.groups.push(Group { rows: vec![object] });
+            continue;
         }
+
         // If there is an existing group for this value, append current object to it
-        else {
-            let index = *groups_map.get(&values_hash).unwrap();
-            let target_group = &mut gitql_object.groups[index];
-            target_group.rows.push(object);
-        }
+        let index = *groups_map.get(&values_hash).unwrap();
+        let target_group = &mut gitql_object.groups[index];
+        target_group.rows.push(object);
     }
 
     Ok(())
@@ -467,16 +474,14 @@ fn execute_aggregation_function_statement(
     statement: &AggregationsStatement,
     gitql_object: &mut GitQLObject,
     alias_table: &HashMap<String, String>,
+    is_query_has_group_by: bool,
 ) -> Result<(), String> {
     // Make sure you have at least one aggregation function to calculate
     let aggregations_map = &statement.aggregations;
     if aggregations_map.is_empty() {
         return Ok(());
     }
 
-    // Used to determine if group by statement is executed before or not
-    let groups_count = gitql_object.len();
-
     // We should run aggregation function for each group
     for group in &mut gitql_object.groups {
         // No need to apply all aggregation if there is no selected elements
@@ -559,7 +564,7 @@ fn execute_aggregation_function_statement(
 
         // In case of group by statement is executed
         // Remove all elements expect the first one
-        if groups_count > 1 {
+        if is_query_has_group_by {
             group.rows.drain(1..);
         }
     }