refactoring: please linter

src/executor/engine.rs

@@ -12,6 +12,10 @@ pub mod cartridge;
 
 /// A metadata storage trait of the cluster.
 pub trait Metadata {
+    /// Get a table by name.
+    ///
+    /// # Errors
+    /// - Failed to get table by name from the metadata.
     fn get_table_segment(
         &self,
         table_name: &str,
@@ -19,6 +23,7 @@ pub trait Metadata {
 
     fn get_exec_waiting_timeout(&self) -> u64;
 
+    #[must_use]
     fn to_name(s: &str) -> String {
         if let (Some('"'), Some('"')) = (s.chars().next(), s.chars().last()) {
             s.to_string()
@@ -46,6 +51,9 @@ pub trait Engine {
     fn clear_metadata(&mut self);
 
     /// Load metadate information to storage
+    ///
+    /// # Errors
+    /// - Failed to load metadata.
     fn load_metadata(&mut self) -> Result<(), QueryPlannerError>;
 
     /// Materialize result motion node to virtual table

src/executor/engine/cartridge.rs

@@ -162,6 +162,10 @@ impl Engine for Runtime {
 }
 
 impl Runtime {
+    /// Create new Tarantool cartridge runtime.
+    ///
+    /// # Errors
+    /// - Failed to detect the correct amount of buckets.
     pub fn new() -> Result<Self, QueryPlannerError> {
         let mut result = Runtime {
             metadata: ClusterAppConfig::new(),

src/executor/engine/cartridge/cache.rs

@@ -28,7 +28,14 @@ pub struct ClusterAppConfig {
     tables: HashMap<String, Table>,
 }
 
+impl Default for ClusterAppConfig {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl ClusterAppConfig {
+    #[must_use]
     pub fn new() -> Self {
         ClusterAppConfig {
             schema: yaml::Yaml::Null,
@@ -53,7 +60,12 @@ impl ClusterAppConfig {
         Err(QueryPlannerError::InvalidClusterSchema)
     }
 
+    /// Get table sharding key.
+    ///
+    /// # Panics
+    /// - Invalid schema.
     #[allow(dead_code)]
+    #[must_use]
     pub fn get_sharding_key_by_space(self, space: &str) -> Vec<String> {
         let mut result = Vec::new();
         let spaces = self.schema["spaces"].as_hash().unwrap();

src/executor/result.rs

@@ -75,6 +75,12 @@ pub struct BoxExecuteFormat {
     pub rows: Vec<BoxExecuteTuple>,
 }
 
+impl Default for BoxExecuteFormat {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl BoxExecuteFormat {
     /// Create empty query result set
     #[allow(dead_code)]

src/executor/vtable.rs

@@ -24,6 +24,12 @@ pub struct VirtualTable {
     hashing: HashMap<String, HashSet<usize>>,
 }
 
+impl Default for VirtualTable {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl VirtualTable {
     #[must_use]
     pub fn new() -> Self {

src/frontend/sql/ast.rs

@@ -137,14 +137,26 @@ pub struct ParseNodes {
     pub(crate) arena: Vec<ParseNode>,
 }
 
+impl Default for ParseNodes {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[allow(dead_code)]
 impl ParseNodes {
     /// Get a node from arena
+    ///
+    /// # Errors
+    /// - Failed to get a node from arena.
     pub fn get_node(&self, node: usize) -> Result<&ParseNode, QueryPlannerError> {
         self.arena.get(node).ok_or(QueryPlannerError::InvalidNode)
     }
 
     /// Get a mutable node from arena
+    ///
+    /// # Errors
+    /// - Failed to get a node from arena.
     pub fn get_mut_node(&mut self, node: usize) -> Result<&mut ParseNode, QueryPlannerError> {
         self.arena
             .get_mut(node)
@@ -159,11 +171,13 @@ impl ParseNodes {
     }
 
     /// Get next node id
+    #[must_use]
     pub fn next_id(&self) -> usize {
         self.arena.len()
     }
 
     /// Constructor
+    #[must_use]
     pub fn new() -> Self {
         ParseNodes { arena: Vec::new() }
     }
@@ -171,6 +185,9 @@ impl ParseNodes {
     /// Adds children to already existing node.
     /// New elements are added to the beginning of the current list
     /// as we use inverted node order.
+    ///
+    /// # Errors
+    /// - Failed to retrieve node from arena.
     pub fn add_child(
         &mut self,
         node: Option<usize>,
@@ -188,6 +205,9 @@ impl ParseNodes {
     }
 
     /// Update node's value (string from pairs)
+    ///
+    /// # Errors
+    /// - Target node is present in the arena.
     pub fn update_value(
         &mut self,
         node: usize,
@@ -226,6 +246,9 @@ pub struct AbstractSyntaxTree {
 #[allow(dead_code)]
 impl AbstractSyntaxTree {
     /// Set the top of AST.
+    ///
+    /// # Errors
+    /// - The new top is not in the arena.
     pub fn set_top(&mut self, top: usize) -> Result<(), QueryPlannerError> {
         self.nodes.get_node(top)?;
         self.top = Some(top);
@@ -233,12 +256,18 @@ impl AbstractSyntaxTree {
     }
 
     /// Get the top of AST.
+    ///
+    /// # Errors
+    /// - AST tree doesn't have a top node.
     pub fn get_top(&self) -> Result<usize, QueryPlannerError> {
         self.top
             .ok_or_else(|| QueryPlannerError::CustomError("No top node found in AST".to_string()))
     }
 
     /// Serialize AST from YAML.
+    ///
+    /// # Errors
+    /// - Failed to parse YAML.
     pub fn from_yaml(s: &str) -> Result<Self, QueryPlannerError> {
         let ast: AbstractSyntaxTree = match serde_yaml::from_str(s) {
             Ok(p) => p,
@@ -249,6 +278,9 @@ impl AbstractSyntaxTree {
 
     /// Constructor.
     /// Builds a tree (nodes are in postorder reverse).
+    ///
+    /// # Errors
+    /// - Failed to parse an SQL query.
     pub fn new(query: &str) -> Result<Self, QueryPlannerError> {
         let mut ast = AbstractSyntaxTree {
             nodes: ParseNodes::new(),

src/frontend/sql/tree.rs

@@ -31,6 +31,7 @@ impl<'n> Iterator for AstIterator<'n> {
 impl<'n> ParseNodes {
     /// Returns an iterator over the children of the node.
     #[allow(dead_code)]
+    #[must_use]
     pub fn ast_iter(&'n self, current: &'n usize) -> AstIterator<'n> {
         AstIterator {
             current,

src/ir/transformation/dnf.rs

@@ -49,7 +49,7 @@
 //!
 //! The corresponding tree:
 //! ```text
-//! 
+//!
 //!                         ┌────┐
 //!                         │ OR │
 //!                         └┬──┬┘