ide: hover for create aggregate (#789)

Author: sbdchd

PLAN.md

@@ -590,7 +590,7 @@ FROM (
 WHERE total_amount > 1000;
 ```
 
-### Rule: aggregate free having condition
+### Rule: aggregate free `having` condition
 
 ```sql
 select a from t group by a having a > 10;
@@ -600,6 +600,21 @@ select a from t group by a having a > 10;
 select a from t where a > 10 group by a;
 ```
 
+### Rule: conflicting function and aggregate definitions
+
+```sql
+create function foo(int) returns int as $$
+  select $1 * 2;
+$$ language sql;
+
+create aggregate foo(int) (
+  sfunc = int4pl,
+  stype = int,
+  initcond = '0'
+);
+-- Query 1 ERROR at Line 1: : ERROR:  function "foo" already exists with same argument types
+```
+
 ### Rule: order direction is redundent
 
 ```sql

crates/squawk_ide/src/hover.rs

@@ -44,6 +44,10 @@ pub fn hover(file: &ast::SourceFile, offset: TextSize) -> Option<String> {
             return hover_function(file, &name_ref, &binder);
         }
 
+        if is_aggregate_ref(&name_ref) {
+            return hover_aggregate(file, &name_ref, &binder);
+        }
+
         if is_select_function_call(&name_ref) {
             // Try function first, but fall back to column if no function found
             // (handles function-call-style column access like `select a(t)`)
@@ -85,6 +89,14 @@ pub fn hover(file: &ast::SourceFile, offset: TextSize) -> Option<String> {
             return format_create_function(&create_function, &binder);
         }
 
+        if let Some(create_aggregate) = name
+            .syntax()
+            .ancestors()
+            .find_map(ast::CreateAggregate::cast)
+        {
+            return format_create_aggregate(&create_aggregate, &binder);
+        }
+
         if let Some(create_schema) = name.syntax().ancestors().find_map(ast::CreateSchema::cast) {
             return format_create_schema(&create_schema);
         }
@@ -353,6 +365,15 @@ fn is_function_ref(name_ref: &ast::NameRef) -> bool {
     false
 }
 
+fn is_aggregate_ref(name_ref: &ast::NameRef) -> bool {
+    for ancestor in name_ref.syntax().ancestors() {
+        if ast::DropAggregate::can_cast(ancestor.kind()) {
+            return true;
+        }
+    }
+    false
+}
+
 fn is_select_function_call(name_ref: &ast::NameRef) -> bool {
     let mut in_call_expr = false;
     let mut in_arg_list = false;
@@ -498,6 +519,53 @@ fn function_schema(
     search_path.first().map(|s| s.to_string())
 }
 
+fn hover_aggregate(
+    file: &ast::SourceFile,
+    name_ref: &ast::NameRef,
+    binder: &binder::Binder,
+) -> Option<String> {
+    let aggregate_ptr = resolve::resolve_name_ref(binder, name_ref)?;
+
+    let root = file.syntax();
+    let aggregate_name_node = aggregate_ptr.to_node(root);
+
+    let create_aggregate = aggregate_name_node
+        .ancestors()
+        .find_map(ast::CreateAggregate::cast)?;
+
+    format_create_aggregate(&create_aggregate, binder)
+}
+
+fn format_create_aggregate(
+    create_aggregate: &ast::CreateAggregate,
+    binder: &binder::Binder,
+) -> Option<String> {
+    let path = create_aggregate.path()?;
+    let segment = path.segment()?;
+    let name = segment.name()?;
+    let aggregate_name = name.syntax().text().to_string();
+
+    let schema = if let Some(qualifier) = path.qualifier() {
+        qualifier.syntax().text().to_string()
+    } else {
+        aggregate_schema(create_aggregate, binder)?
+    };
+
+    let param_list = create_aggregate.param_list()?;
+    let params = param_list.syntax().text().to_string();
+
+    Some(format!("aggregate {}.{}{}", schema, aggregate_name, params))
+}
+
+fn aggregate_schema(
+    create_aggregate: &ast::CreateAggregate,
+    binder: &binder::Binder,
+) -> Option<String> {
+    let position = create_aggregate.syntax().text_range().start();
+    let search_path = binder.search_path_at(position);
+    search_path.first().map(|s| s.to_string())
+}
+
 #[cfg(test)]
 mod test {
     use crate::hover::hover;
@@ -1003,6 +1071,114 @@ drop function foo$0();
         ");
     }
 
+    #[test]
+    fn hover_on_drop_function_overloaded() {
+        assert_snapshot!(check_hover("
+create function add(complex) returns complex as $$ select null $$ language sql;
+create function add(bigint) returns bigint as $$ select 1 $$ language sql;
+drop function add$0(complex);
+"), @r"
+        hover: function public.add(complex) returns complex
+          ╭▸ 
+        4 │ drop function add(complex);
+          ╰╴                ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_function_second_overload() {
+        assert_snapshot!(check_hover("
+create function add(complex) returns complex as $$ select null $$ language sql;
+create function add(bigint) returns bigint as $$ select 1 $$ language sql;
+drop function add$0(bigint);
+"), @r"
+        hover: function public.add(bigint) returns bigint
+          ╭▸ 
+        4 │ drop function add(bigint);
+          ╰╴                ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_aggregate() {
+        assert_snapshot!(check_hover("
+create aggregate myavg(int) (sfunc = int4_avg_accum, stype = _int8);
+drop aggregate myavg$0(int);
+"), @r"
+        hover: aggregate public.myavg(int)
+          ╭▸ 
+        3 │ drop aggregate myavg(int);
+          ╰╴                   ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_aggregate_with_schema() {
+        assert_snapshot!(check_hover("
+create aggregate myschema.myavg(int) (sfunc = int4_avg_accum, stype = _int8);
+drop aggregate myschema.myavg$0(int);
+"), @r"
+        hover: aggregate myschema.myavg(int)
+          ╭▸ 
+        3 │ drop aggregate myschema.myavg(int);
+          ╰╴                            ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_create_aggregate_definition() {
+        assert_snapshot!(check_hover("
+create aggregate myavg$0(int) (sfunc = int4_avg_accum, stype = _int8);
+"), @r"
+        hover: aggregate public.myavg(int)
+          ╭▸ 
+        2 │ create aggregate myavg(int) (sfunc = int4_avg_accum, stype = _int8);
+          ╰╴                     ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_aggregate_with_search_path() {
+        assert_snapshot!(check_hover(r#"
+set search_path to myschema;
+create aggregate myavg(int) (sfunc = int4_avg_accum, stype = _int8);
+drop aggregate myavg$0(int);
+"#), @r"
+        hover: aggregate myschema.myavg(int)
+          ╭▸ 
+        4 │ drop aggregate myavg(int);
+          ╰╴                   ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_aggregate_overloaded() {
+        assert_snapshot!(check_hover("
+create aggregate sum(complex) (sfunc = complex_add, stype = complex, initcond = '(0,0)');
+create aggregate sum(bigint) (sfunc = bigint_add, stype = bigint, initcond = '0');
+drop aggregate sum$0(complex);
+"), @r"
+        hover: aggregate public.sum(complex)
+          ╭▸ 
+        4 │ drop aggregate sum(complex);
+          ╰╴                 ─ hover
+        ");
+    }
+
+    #[test]
+    fn hover_on_drop_aggregate_second_overload() {
+        assert_snapshot!(check_hover("
+create aggregate sum(complex) (sfunc = complex_add, stype = complex, initcond = '(0,0)');
+create aggregate sum(bigint) (sfunc = bigint_add, stype = bigint, initcond = '0');
+drop aggregate sum$0(bigint);
+"), @r"
+        hover: aggregate public.sum(bigint)
+          ╭▸ 
+        4 │ drop aggregate sum(bigint);
+          ╰╴                 ─ hover
+        ");
+    }
+
     #[test]
     fn hover_on_select_function_call() {
         assert_snapshot!(check_hover("