feat(completions): respect table aliases, complete in JOINs (#388)

* add comment, rename

* add filtering

* feat(completions): recognize table aliases

* non exhaustive

* ok

Author: juleswritescode

crates/pgt_completions/src/context.rs

@@ -13,6 +13,7 @@ pub enum ClauseType {
     Select,
     Where,
     From,
+    Join,
     Update,
     Delete,
 }
@@ -33,6 +34,7 @@ impl TryFrom<&str> for ClauseType {
             "from" => Ok(Self::From),
             "update" => Ok(Self::Update),
             "delete" => Ok(Self::Delete),
+            "join" => Ok(Self::Join),
             _ => {
                 let message = format!("Unimplemented ClauseType: {}", value);
 
@@ -106,14 +108,35 @@ pub(crate) struct CompletionContext<'a> {
     pub schema_cache: &'a SchemaCache,
     pub position: usize,
 
-    pub schema_name: Option<String>,
+    /// If the cursor is on a node that uses dot notation
+    /// to specify an alias or schema, this will hold the schema's or
+    /// alias's name.
+    ///
+    /// Here, `auth` is a schema name:
+    /// ```sql
+    /// select * from auth.users;
+    /// ```
+    ///
+    /// Here, `u` is an alias name:
+    /// ```sql
+    /// select
+    ///     *
+    /// from
+    ///     auth.users u
+    ///     left join identities i
+    ///     on u.id = i.user_id;
+    /// ```
+    pub schema_or_alias_name: Option<String>,
     pub wrapping_clause_type: Option<ClauseType>,
 
     pub wrapping_node_kind: Option<WrappingNode>,
 
     pub is_invocation: bool,
     pub wrapping_statement_range: Option<tree_sitter::Range>,
 
+    /// Some incomplete statements can't be correctly parsed by TreeSitter.
+    pub is_in_error_node: bool,
+
     pub mentioned_relations: HashMap<Option<String>, HashSet<String>>,
 
     pub mentioned_table_aliases: HashMap<String, String>,
@@ -127,13 +150,14 @@ impl<'a> CompletionContext<'a> {
             schema_cache: params.schema,
             position: usize::from(params.position),
             node_under_cursor: None,
-            schema_name: None,
+            schema_or_alias_name: None,
             wrapping_clause_type: None,
             wrapping_node_kind: None,
             wrapping_statement_range: None,
             is_invocation: false,
             mentioned_relations: HashMap::new(),
             mentioned_table_aliases: HashMap::new(),
+            is_in_error_node: false,
         };
 
         ctx.gather_tree_context();
@@ -246,34 +270,77 @@ impl<'a> CompletionContext<'a> {
                 self.wrapping_statement_range = Some(parent_node.range());
             }
             "invocation" => self.is_invocation = true,
-
             _ => {}
         }
 
+        // try to gather context from the siblings if we're within an error node.
+        if self.is_in_error_node {
+            let mut next_sibling = current_node.next_named_sibling();
+            while let Some(n) = next_sibling {
+                if n.kind().starts_with("keyword_") {
+                    if let Some(txt) = self.get_ts_node_content(n).and_then(|txt| match txt {
+                        NodeText::Original(txt) => Some(txt),
+                        NodeText::Replaced => None,
+                    }) {
+                        match txt {
+                            "where" | "update" | "select" | "delete" | "from" | "join" => {
+                                self.wrapping_clause_type = txt.try_into().ok();
+                                break;
+                            }
+                            _ => {}
+                        }
+                    };
+                }
+                next_sibling = n.next_named_sibling();
+            }
+            let mut prev_sibling = current_node.prev_named_sibling();
+            while let Some(n) = prev_sibling {
+                if n.kind().starts_with("keyword_") {
+                    if let Some(txt) = self.get_ts_node_content(n).and_then(|txt| match txt {
+                        NodeText::Original(txt) => Some(txt),
+                        NodeText::Replaced => None,
+                    }) {
+                        match txt {
+                            "where" | "update" | "select" | "delete" | "from" | "join" => {
+                                self.wrapping_clause_type = txt.try_into().ok();
+                                break;
+                            }
+                            _ => {}
+                        }
+                    };
+                }
+                prev_sibling = n.prev_named_sibling();
+            }
+        }
+
         match current_node_kind {
-            "object_reference" => {
+            "object_reference" | "field" => {
                 let content = self.get_ts_node_content(current_node);
                 if let Some(node_txt) = content {
                     match node_txt {
                         NodeText::Original(txt) => {
                             let parts: Vec<&str> = txt.split('.').collect();
                             if parts.len() == 2 {
-                                self.schema_name = Some(parts[0].to_string());
+                                self.schema_or_alias_name = Some(parts[0].to_string());
                             }
                         }
                         NodeText::Replaced => {}
                     }
                 }
             }
 
-            "where" | "update" | "select" | "delete" | "from" => {
+            "where" | "update" | "select" | "delete" | "from" | "join" => {
                 self.wrapping_clause_type = current_node_kind.try_into().ok();
             }
 
             "relation" | "binary_expression" | "assignment" => {
                 self.wrapping_node_kind = current_node_kind.try_into().ok();
             }
 
+            "ERROR" => {
+                self.is_in_error_node = true;
+            }
+
             _ => {}
         }
 
@@ -380,7 +447,10 @@ mod tests {
 
             let ctx = CompletionContext::new(&params);
 
-            assert_eq!(ctx.schema_name, expected_schema.map(|f| f.to_string()));
+            assert_eq!(
+                ctx.schema_or_alias_name,
+                expected_schema.map(|f| f.to_string())
+            );
         }
     }
 

crates/pgt_completions/src/providers/columns.rs

@@ -28,7 +28,10 @@ pub fn complete_columns<'a>(ctx: &CompletionContext<'a>, builder: &mut Completio
 mod tests {
     use crate::{
         CompletionItem, CompletionItemKind, complete,
-        test_helper::{CURSOR_POS, InputQuery, get_test_deps, get_test_params},
+        test_helper::{
+            CURSOR_POS, CompletionAssertion, InputQuery, assert_complete_results, get_test_deps,
+            get_test_params,
+        },
     };
 
     struct TestCase {
@@ -168,9 +171,9 @@ mod tests {
             ("name", "Table: public.users"),
             ("narrator", "Table: public.audio_books"),
             ("narrator_id", "Table: private.audio_books"),
+            ("id", "Table: public.audio_books"),
             ("name", "Schema: pg_catalog"),
             ("nameconcatoid", "Schema: pg_catalog"),
-            ("nameeq", "Schema: pg_catalog"),
         ]
         .into_iter()
         .map(|(label, schema)| LabelAndDesc {
@@ -325,4 +328,107 @@ mod tests {
             );
         }
     }
+
+    #[tokio::test]
+    async fn filters_out_by_aliases() {
+        let setup = r#"
+            create schema auth;
+
+            create table auth.users (
+                uid serial primary key,
+                name text not null,
+                email text unique not null
+            );
+
+            create table auth.posts (
+                pid serial primary key,
+                user_id int not null references auth.users(uid),
+                title text not null,
+                content text,
+                created_at timestamp default now()
+            );
+        "#;
+
+        // test in SELECT clause
+        assert_complete_results(
+            format!(
+                "select u.id, p.{} from auth.users u join auth.posts p on u.id = p.user_id;",
+                CURSOR_POS
+            )
+            .as_str(),
+            vec![
+                CompletionAssertion::LabelNotExists("uid".to_string()),
+                CompletionAssertion::LabelNotExists("name".to_string()),
+                CompletionAssertion::LabelNotExists("email".to_string()),
+                CompletionAssertion::Label("content".to_string()),
+                CompletionAssertion::Label("created_at".to_string()),
+                CompletionAssertion::Label("pid".to_string()),
+                CompletionAssertion::Label("title".to_string()),
+                CompletionAssertion::Label("user_id".to_string()),
+            ],
+            setup,
+        )
+        .await;
+
+        // test in JOIN clause
+        assert_complete_results(
+            format!(
+                "select u.id, p.content from auth.users u join auth.posts p on u.id = p.{};",
+                CURSOR_POS
+            )
+            .as_str(),
+            vec![
+                CompletionAssertion::LabelNotExists("uid".to_string()),
+                CompletionAssertion::LabelNotExists("name".to_string()),
+                CompletionAssertion::LabelNotExists("email".to_string()),
+                // primary keys are preferred
+                CompletionAssertion::Label("pid".to_string()),
+                CompletionAssertion::Label("content".to_string()),
+                CompletionAssertion::Label("created_at".to_string()),
+                CompletionAssertion::Label("title".to_string()),
+                CompletionAssertion::Label("user_id".to_string()),
+            ],
+            setup,
+        )
+        .await;
+    }
+
+    #[tokio::test]
+    async fn does_not_complete_cols_in_join_clauses() {
+        let setup = r#"
+            create schema auth;
+
+            create table auth.users (
+                uid serial primary key,
+                name text not null,
+                email text unique not null
+            );
+
+            create table auth.posts (
+                pid serial primary key,
+                user_id int not null references auth.users(uid),
+                title text not null,
+                content text,
+                created_at timestamp default now()
+            );
+        "#;
+
+        /*
+         * We are not in the "ON" part of the JOIN clause, so we should not complete columns.
+         */
+        assert_complete_results(
+            format!(
+                "select u.id, p.content from auth.users u join auth.{}",
+                CURSOR_POS
+            )
+            .as_str(),
+            vec![
+                CompletionAssertion::KindNotExists(CompletionItemKind::Column),
+                CompletionAssertion::LabelAndKind("posts".to_string(), CompletionItemKind::Table),
+                CompletionAssertion::LabelAndKind("users".to_string(), CompletionItemKind::Table),
+            ],
+            setup,
+        )
+        .await;
+    }
 }

crates/pgt_completions/src/providers/helper.rs

@@ -7,7 +7,7 @@ pub(crate) fn get_completion_text_with_schema(
     item_name: &str,
     item_schema_name: &str,
 ) -> Option<CompletionText> {
-    if item_schema_name == "public" || ctx.schema_name.is_some() {
+    if item_schema_name == "public" || ctx.schema_or_alias_name.is_some() {
         None
     } else {
         let node = ctx.node_under_cursor.unwrap();

crates/pgt_completions/src/providers/schemas.rs

@@ -59,6 +59,8 @@ mod tests {
                     "private".to_string(),
                     CompletionItemKind::Schema,
                 ),
+                // users table still preferred over system schemas
+                CompletionAssertion::LabelAndKind("users".to_string(), CompletionItemKind::Table),
                 CompletionAssertion::LabelAndKind(
                     "information_schema".to_string(),
                     CompletionItemKind::Schema,
@@ -71,7 +73,6 @@ mod tests {
                     "pg_toast".to_string(),
                     CompletionItemKind::Schema,
                 ),
-                CompletionAssertion::LabelAndKind("users".to_string(), CompletionItemKind::Table),
             ],
             setup,
         )

crates/pgt_completions/src/providers/tables.rs

@@ -273,4 +273,37 @@ mod tests {
         )
         .await;
     }
+
+    #[tokio::test]
+    async fn suggests_tables_in_join() {
+        let setup = r#"
+            create schema auth;
+
+            create table auth.users (
+                uid serial primary key,
+                name text not null,
+                email text unique not null
+            );
+
+            create table auth.posts (
+                pid serial primary key,
+                user_id int not null references auth.users(uid),
+                title text not null,
+                content text,
+                created_at timestamp default now()
+            );
+        "#;
+
+        assert_complete_results(
+            format!("select * from auth.users u join {}", CURSOR_POS).as_str(),
+            vec![
+                CompletionAssertion::LabelAndKind("public".into(), CompletionItemKind::Schema),
+                CompletionAssertion::LabelAndKind("auth".into(), CompletionItemKind::Schema),
+                CompletionAssertion::LabelAndKind("posts".into(), CompletionItemKind::Table), // self-join
+                CompletionAssertion::LabelAndKind("users".into(), CompletionItemKind::Table),
+            ],
+            setup,
+        )
+        .await;
+    }
 }