Refine queryRow/queryValue/queryColumn errors and drop dead fields guard

async_postgres/pg_client.nim

@@ -1188,8 +1188,6 @@ proc queryRowOpt*(
   ## Execute a query and return the first row, or `none` if no rows.
   let qr = await conn.query(sql, params, resultFormat = resultFormat, timeout = timeout)
   if qr.rowCount > 0:
-    if qr.fields.len > 0 and qr.data.fields.len == 0:
-      qr.data.fields = qr.fields
     return some(initRow(qr.data, 0))
   else:
     return none(Row)
@@ -1202,11 +1200,11 @@ proc queryRow*(
     timeout: Duration = ZeroDuration,
 ): Future[Row] {.async.} =
   ## Execute a query and return the first row.
-  ## Raises `PgError` if no rows are returned.
+  ## Raises `PgNoRowsError` if no rows are returned.
   let row =
     await conn.queryRowOpt(sql, params, resultFormat = resultFormat, timeout = timeout)
   if row.isNone:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   return row.get
 
 proc queryValue*(
@@ -1216,13 +1214,13 @@ proc queryValue*(
     timeout: Duration = ZeroDuration,
 ): Future[string] {.async.} =
   ## Execute a query and return the first column of the first row as a string.
-  ## Raises PgError if no rows are returned or the value is NULL.
+  ## Raises `PgNoRowsError` if no rows are returned, or `PgNullError` if the value is NULL.
   let qr = await conn.query(sql, params, timeout = timeout)
   if qr.rowCount == 0:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   let row = initRow(qr.data, 0)
   if row.isNull(0):
-    raise newException(PgError, "Query returned NULL")
+    raise newException(PgNullError, "Query returned NULL")
   return row.getStr(0)
 
 proc queryValue*[T](
@@ -1233,14 +1231,14 @@ proc queryValue*[T](
     timeout: Duration = ZeroDuration,
 ): Future[T] {.async.} =
   ## Execute a query and return the first column of the first row as `T`.
-  ## Raises PgError if no rows are returned or the value is NULL.
+  ## Raises `PgNoRowsError` if no rows are returned, or `PgNullError` if the value is NULL.
   ## Supported types: int32, int64, float64, bool, string.
   let qr = await conn.query(sql, params, timeout = timeout)
   if qr.rowCount == 0:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   let row = initRow(qr.data, 0)
   if row.isNull(0):
-    raise newException(PgError, "Query returned NULL")
+    raise newException(PgNullError, "Query returned NULL")
   return row.get(0, T)
 
 proc queryValueOpt*(
@@ -1349,12 +1347,12 @@ proc queryColumn*(
     timeout: Duration = ZeroDuration,
 ): Future[seq[string]] {.async.} =
   ## Execute a query and return the first column of all rows as strings.
-  ## Raises PgTypeError if any value is NULL.
+  ## Raises `PgNullError` if any value is NULL.
   let qr = await conn.query(sql, params, timeout = timeout)
   for i in 0 ..< qr.rowCount:
     let row = initRow(qr.data, i)
     if row.isNull(0):
-      raise newException(PgTypeError, "NULL value in column")
+      raise newException(PgNullError, "NULL value in column")
     result.add(row.getStr(0))
 
 proc prepareImpl(

async_postgres/pg_errors.nim

@@ -13,6 +13,13 @@ type
   PgTypeError* = object of PgError
     ## Raised when a PostgreSQL value cannot be converted to the requested Nim type.
 
+  PgNoRowsError* = object of PgError
+    ## Raised by single-row/single-value queries when the result set is empty.
+
+  PgNullError* = object of PgError
+    ## Raised by single-value queries when the value is SQL NULL and the
+    ## caller requested a non-nullable result.
+
   PgConnectionError* = object of PgError
     ## Connection failures, disconnections, SSL/auth errors.
 

async_postgres/pg_pool.nim

@@ -745,8 +745,6 @@ proc queryRowOpt*(
   ## Execute a query and return the first row, or `none` if no rows.
   let qr = await pool.query(sql, params, resultFormat, timeout)
   if qr.rowCount > 0:
-    if qr.fields.len > 0 and qr.data.fields.len == 0:
-      qr.data.fields = qr.fields
     return some(initRow(qr.data, 0))
   return none(Row)
 
@@ -758,11 +756,11 @@ proc queryRow*(
     timeout: Duration = ZeroDuration,
 ): Future[Row] {.async.} =
   ## Execute a query and return the first row.
-  ## Raises `PgError` if no rows are returned.
+  ## Raises `PgNoRowsError` if no rows are returned.
   let row =
     await pool.queryRowOpt(sql, params, resultFormat = resultFormat, timeout = timeout)
   if row.isNone:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   return row.get
 
 proc queryValue*(
@@ -772,13 +770,13 @@ proc queryValue*(
     timeout: Duration = ZeroDuration,
 ): Future[string] {.async.} =
   ## Execute a query and return the first column of the first row as a string.
-  ## Raises `PgError` if no rows or the value is NULL.
+  ## Raises `PgNoRowsError` if no rows are returned, or `PgNullError` if the value is NULL.
   let qr = await pool.query(sql, params, timeout = timeout)
   if qr.rowCount == 0:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   let row = initRow(qr.data, 0)
   if row.isNull(0):
-    raise newException(PgError, "Query returned NULL")
+    raise newException(PgNullError, "Query returned NULL")
   return row.getStr(0)
 
 proc queryValue*[T](
@@ -789,13 +787,13 @@ proc queryValue*[T](
     timeout: Duration = ZeroDuration,
 ): Future[T] {.async.} =
   ## Execute a query and return the first column of the first row as `T`.
-  ## Raises `PgError` if no rows or the value is NULL.
+  ## Raises `PgNoRowsError` if no rows are returned, or `PgNullError` if the value is NULL.
   let qr = await pool.query(sql, params, timeout = timeout)
   if qr.rowCount == 0:
-    raise newException(PgError, "Query returned no rows")
+    raise newException(PgNoRowsError, "Query returned no rows")
   let row = initRow(qr.data, 0)
   if row.isNull(0):
-    raise newException(PgError, "Query returned NULL")
+    raise newException(PgNullError, "Query returned NULL")
   return row.get(0, T)
 
 proc queryValueOpt*(
@@ -901,12 +899,12 @@ proc queryColumn*(
     timeout: Duration = ZeroDuration,
 ): Future[seq[string]] {.async.} =
   ## Execute a query and return the first column of all rows as strings.
-  ## Raises PgTypeError if any value is NULL.
+  ## Raises `PgNullError` if any value is NULL.
   let qr = await pool.query(sql, params, timeout = timeout)
   for i in 0 ..< qr.rowCount:
     let row = initRow(qr.data, i)
     if row.isNull(0):
-      raise newException(PgTypeError, "NULL value in column")
+      raise newException(PgNullError, "NULL value in column")
     result.add(row.getStr(0))
 
 proc simpleQuery*(pool: PgPool, sql: string): Future[seq[QueryResult]] {.async.} =

tests/test_e2e.nim

@@ -4952,7 +4952,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryRow("SELECT 1 WHERE false")
-      except PgError:
+      except PgNoRowsError:
         raised = true
       doAssert raised
       await conn.close()
@@ -4974,7 +4974,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryValue("SELECT 1 WHERE false")
-      except PgError:
+      except PgNoRowsError:
         raised = true
       doAssert raised
       await conn.close()
@@ -4987,7 +4987,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryValue("SELECT NULL::text")
-      except PgError:
+      except PgNullError:
         raised = true
       doAssert raised
       await conn.close()
@@ -5043,7 +5043,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryValue(int32, "SELECT 1 WHERE false")
-      except PgError:
+      except PgNoRowsError:
         raised = true
       doAssert raised
       await conn.close()
@@ -5056,7 +5056,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryValue(int64, "SELECT NULL::int8")
-      except PgError:
+      except PgNullError:
         raised = true
       doAssert raised
       await conn.close()
@@ -5184,7 +5184,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await conn.queryColumn("SELECT NULL::text")
-      except PgTypeError:
+      except PgNullError:
         raised = true
       doAssert raised
       await conn.close()
@@ -5271,7 +5271,7 @@ suite "E2E: Convenience Query Methods":
       var raised = false
       try:
         discard await pool.queryRow("SELECT 1 WHERE false")
-      except PgError:
+      except PgNoRowsError:
         raised = true
       doAssert raised
       await pool.close()
@@ -5287,6 +5287,32 @@ suite "E2E: Convenience Query Methods":
 
     waitFor t()
 
+  test "pool queryValue raises on no rows":
+    proc t() {.async.} =
+      let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
+      var raised = false
+      try:
+        discard await pool.queryValue("SELECT 1 WHERE false")
+      except PgNoRowsError:
+        raised = true
+      doAssert raised
+      await pool.close()
+
+    waitFor t()
+
+  test "pool queryValue raises on NULL":
+    proc t() {.async.} =
+      let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
+      var raised = false
+      try:
+        discard await pool.queryValue("SELECT NULL::text")
+      except PgNullError:
+        raised = true
+      doAssert raised
+      await pool.close()
+
+    waitFor t()
+
   test "pool queryExists":
     proc t() {.async.} =
       let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
@@ -5336,6 +5362,32 @@ suite "E2E: Convenience Query Methods":
 
     waitFor t()
 
+  test "pool queryValue with typedesc raises on no rows":
+    proc t() {.async.} =
+      let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
+      var raised = false
+      try:
+        discard await pool.queryValue(int32, "SELECT 1 WHERE false")
+      except PgNoRowsError:
+        raised = true
+      doAssert raised
+      await pool.close()
+
+    waitFor t()
+
+  test "pool queryValue with typedesc raises on NULL":
+    proc t() {.async.} =
+      let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))
+      var raised = false
+      try:
+        discard await pool.queryValue(int64, "SELECT NULL::int8")
+      except PgNullError:
+        raised = true
+      doAssert raised
+      await pool.close()
+
+    waitFor t()
+
   test "pool queryValueOrDefault with typedesc":
     proc t() {.async.} =
       let pool = await newPool(initPoolConfig(plainConfig(), minSize = 1, maxSize = 2))