Improve error handling & return meaningful error messages (#246)

* meaningful error

* improved error handling

* fmt

* clippy fix

* throw error on the impoissble cases

* remove unused error

* simplify TableNameInferenceFailedInWhere

* fix

* fix

* clippy fail on warning

* remove unncessary type cast

Author: JasonShin

.github/workflows/rust.yaml

@@ -97,7 +97,7 @@ jobs:
           cache-provider: "github"
 
       - name: Run clippy
-        run: cargo clippy
+        run: cargo clippy --lib --all-features -- -D warnings
 
       - name: Run rustfmt
         run: cargo fmt -- --check

src/ts_generator/errors.rs

@@ -32,6 +32,22 @@ pub enum TsGeneratorError {
   TableFactorWhileProcessingTableWithJoins(String),
   #[error("[E014] Failed to find a table name from a FROM statement: statement: `{0}`")]
   UnknownErrorWhileProcessingTableWithJoins(String),
+  #[error("[E015] Table expressions are not supported in INSERT statements - query: `{0}`")]
+  TableExpressionInInsertStatement(String),
+  #[error("[E016] Column '{column}' not found in table '{table}'. Available columns: {available_columns}")]
+  ColumnNotFoundInTable {
+    column: String,
+    table: String,
+    available_columns: String,
+  },
+  #[error("[E017] Failed to process INSERT statement: {reason}. Query: `{query}`")]
+  InsertStatementProcessingFailed { reason: String, query: String },
+  #[error("[E018] Failed to process UPDATE statement: {reason}. Query: `{query}`")]
+  UpdateStatementProcessingFailed { reason: String, query: String },
+  #[error("[E019] Table '{table}' not found in database schema. Check that the table exists and is accessible.")]
+  TableNotFoundInSchema { table: String },
+  #[error("[E020] Failed to infer table name while processing WHERE clause. Query: `{query}`")]
+  TableNameInferenceFailedInWhere { query: String },
   #[error("Unknown error: `{0}`")]
   Unknown(String),
 }

src/ts_generator/generator.rs

@@ -77,8 +77,8 @@ pub fn write_single_ts_file(sqls_to_write: String) -> Result<()> {
   ))?;
 
   let parent_output_path: Option<&Path> = output.parent();
-  if parent_output_path.is_some() {
-    fs::create_dir_all(parent_output_path.unwrap())?;
+  if let Some(parent_output_path) = parent_output_path {
+    fs::create_dir_all(parent_output_path)?;
   }
 
   let mut file_to_write = OpenOptions::new()

src/ts_generator/sql_parser/expressions/translate_expr.rs

@@ -124,15 +124,17 @@ pub async fn get_sql_query_param(
   single_table_name: &Option<&str>,
   table_with_joins: &Option<Vec<TableWithJoins>>,
   db_conn: &DBConn,
-) -> Option<(TsFieldType, bool, Option<String>)> {
+) -> Result<Option<(TsFieldType, bool, Option<String>)>, TsGeneratorError> {
   let table_name: Option<String>;
 
   if table_with_joins.is_some() {
     table_name = translate_table_from_expr(table_with_joins, &left.clone()).ok();
   } else if single_table_name.is_some() {
     table_name = single_table_name.map(|x| x.to_string());
   } else {
-    panic!("failed to find an appropriate table name while processing WHERE statement")
+    return Err(TsGeneratorError::TableNameInferenceFailedInWhere {
+      query: left.to_string(),
+    });
   }
 
   let column_name = translate_column_name_expr(left);
@@ -149,15 +151,27 @@ pub async fn get_sql_query_param(
         .await
         .fetch_table(&table_names, db_conn)
         .await
-        .unwrap_or_else(|| panic!("Failed to fetch columns for table {table_name}"));
+        .ok_or_else(|| TsGeneratorError::TableNotFoundInSchema {
+          table: table_name.clone(),
+        })?;
 
       // get column and return TsFieldType
-      let column = columns
-        .get(column_name.as_str())
-        .unwrap_or_else(|| panic!("Failed to find the column from the table schema of {table_name}"));
-      Some((column.field_type.to_owned(), column.is_nullable, Some(expr_placeholder)))
+      let column = columns.get(column_name.as_str()).ok_or_else(|| {
+        let available_columns = columns.keys().map(|k| k.as_str()).collect::<Vec<_>>().join(", ");
+        TsGeneratorError::ColumnNotFoundInTable {
+          column: column_name.clone(),
+          table: table_name.clone(),
+          available_columns,
+        }
+      })?;
+
+      Ok(Some((
+        column.field_type.to_owned(),
+        column.is_nullable,
+        Some(expr_placeholder),
+      )))
     }
-    _ => None,
+    _ => Ok(None),
   }
 }
 
@@ -298,7 +312,7 @@ pub async fn translate_expr(
     // OPERATORS START //
     /////////////////////
     Expr::BinaryOp { left, op: _, right } => {
-      let param = get_sql_query_param(left, right, single_table_name, table_with_joins, db_conn).await;
+      let param = get_sql_query_param(left, right, single_table_name, table_with_joins, db_conn).await?;
       if let Some((value, is_nullable, index)) = param {
         let _ = ts_query.insert_param(&value, &is_nullable, &index);
         Ok(())
@@ -341,7 +355,7 @@ pub async fn translate_expr(
           table_with_joins,
           db_conn,
         )
-        .await;
+        .await?;
 
         if let Some((value, is_nullable, index)) = result {
           let array_item = TsFieldType::Array(Box::new(value));
@@ -369,8 +383,8 @@ pub async fn translate_expr(
       low,
       high,
     } => {
-      let low = get_sql_query_param(expr, low, single_table_name, table_with_joins, db_conn).await;
-      let high = get_sql_query_param(expr, high, single_table_name, table_with_joins, db_conn).await;
+      let low = get_sql_query_param(expr, low, single_table_name, table_with_joins, db_conn).await?;
+      let high = get_sql_query_param(expr, high, single_table_name, table_with_joins, db_conn).await?;
       if let Some((value, is_nullable, placeholder)) = low {
         ts_query.insert_param(&value, &is_nullable, &placeholder)?;
       }
@@ -731,16 +745,35 @@ pub async fn translate_assignment(
   let value = get_expr_placeholder(&assignment.value);
 
   if value.is_some() {
-    let table_details = &DB_SCHEMA
+    let table_details = DB_SCHEMA
       .lock()
       .await
       .fetch_table(&vec![table_name], db_conn)
       .await
-      .unwrap();
-    let column_name = translate_column_name_assignment(assignment).unwrap();
-    let field = table_details
-      .get(&column_name)
-      .unwrap_or_else(|| panic!("Failed to find the column detail for {column_name}"));
+      .ok_or_else(|| TsGeneratorError::TableNotFoundInSchema {
+        table: table_name.to_string(),
+      })?;
+
+    let column_name = translate_column_name_assignment(assignment).ok_or_else(|| {
+      TsGeneratorError::UpdateStatementProcessingFailed {
+        reason: "Failed to extract column name from assignment".to_string(),
+        query: format!("UPDATE {} SET {} = ...", table_name, assignment),
+      }
+    })?;
+
+    let field = table_details.get(&column_name).ok_or_else(|| {
+      let available_columns = table_details
+        .keys()
+        .map(|k| k.as_str())
+        .collect::<Vec<_>>()
+        .join(", ");
+      TsGeneratorError::ColumnNotFoundInTable {
+        column: column_name.clone(),
+        table: table_name.to_string(),
+        available_columns,
+      }
+    })?;
+
     let _ = ts_query.insert_param(&field.field_type, &field.is_nullable, &value);
   }
   Ok(())

src/ts_generator/sql_parser/translate_insert.rs

@@ -41,24 +41,32 @@ pub async fn translate_insert(
           if placeholder.is_some() {
             let match_col = &columns
               .get(column)
-              .unwrap_or_else(|| {
-                panic!(
-                  r#"
-Failed to process values of insert statement as column names are not provided or incorrectly specified
-
-Try specifying column names
-```
-INSERT INTO table_name (column1, column2, column3, ...)
-VALUES (value1, value2, value3, ...);
-```
-              "#
-                )
-              })
+              .ok_or_else(|| {
+                TsGeneratorError::InsertStatementProcessingFailed {
+                  reason: format!(
+                    "Column at position {} is not provided in the column list. Expected {} columns but found {} values.",
+                    column, columns.len(), values.len()
+                  ),
+                  query: format!(
+                    "INSERT INTO {} VALUES (...). Try specifying column names explicitly: INSERT INTO {} (column1, column2, ...) VALUES (...)",
+                    table_name, table_name
+                  ),
+                }
+              })?
               .value;
 
-            let field = table_details
-              .get(match_col.as_str())
-              .unwrap_or_else(|| panic!("Column {match_col} is not found while processing insert params"));
+            let field = table_details.get(match_col.as_str()).ok_or_else(|| {
+              let available_columns = table_details
+                .keys()
+                .map(|k| k.as_str())
+                .collect::<Vec<_>>()
+                .join(", ");
+              TsGeneratorError::ColumnNotFoundInTable {
+                column: match_col.clone(),
+                table: table_name.to_string(),
+                available_columns,
+              }
+            })?;
 
             if value.to_string() == "?" {
               // If the placeholder is `'?'`, we can process it using insert_value_params and generate nested params type
@@ -104,7 +112,12 @@ VALUES (value1, value2, value3, ...);
     SetExpr::Update(update) => translate_stmt(ts_query, &update, None, conn).await?,
     SetExpr::Delete(delete) => translate_stmt(ts_query, &delete, None, conn).await?,
     SetExpr::Merge(merge) => translate_stmt(ts_query, &merge, None, conn).await?,
-    SetExpr::Table(_) => unimplemented!("Table expressions are not supported in INSERT statements"),
+    SetExpr::Table(table) => {
+      return Err(TsGeneratorError::TableExpressionInInsertStatement(format!(
+        "INSERT INTO {} ... FROM {}",
+        table_name, table
+      )));
+    }
   }
 
   Ok(())

src/ts_generator/sql_parser/translate_query.rs

@@ -123,8 +123,12 @@ pub async fn translate_select(
     let mut table_name: Option<&str> = None;
     if full_table_with_joins.is_some() && !full_table_with_joins.as_ref().unwrap().is_empty() {
       table_name_owned = Some(
-        translate_table_with_joins(full_table_with_joins, &select_item)
-          .unwrap_or_else(|_| panic!("{}", format!("Default FROM table is not found from the query {select}"))),
+        translate_table_with_joins(full_table_with_joins, &select_item).map_err(|_| {
+          TsGeneratorError::UnknownErrorWhileProcessingTableWithJoins(format!(
+            "Default FROM table is not found from the query: {}. Ensure your query has a valid FROM clause.",
+            select
+          ))
+        })?,
       );
       table_name = table_name_owned.as_deref();
     }

src/ts_generator/types/ts_query.rs

@@ -363,7 +363,7 @@ impl TsQuery {
           .and_then(|m| m.as_str().parse::<i32>().ok())
           .ok_or(TsGeneratorError::UnknownPlaceholder(format!(
             "{placeholder} is not a valid placeholder parameter in PostgreSQL"
-          )))? as i32
+          )))?
       } else {
         // No pattern matches the provided placeholder, simply exit out of the function
         return Ok(());