SNOW-1936603: fix limit 0 bug with show

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ### Snowpark Python API Updates
 
+#### Bug Fixes
+
+- Fixed a bug where `df.show` would still show rows after a `df.limit(0)` call was applied to it.
+
 ### Snowpark Local Testing Updates
 
 #### New Features

src/snowflake/snowpark/_internal/analyzer/select_statement.py

@@ -1375,7 +1375,7 @@ def limit(self, n: int, *, offset: int = 0) -> "SelectStatement":
         else:
             new = copy(self)
             new.from_ = self.from_.to_subqueryable()
-            new.limit_ = min(self.limit_, n) if self.limit_ else n
+            new.limit_ = min(self.limit_, n) if self.limit_ is not None else n
             new.offset = offset or self.offset
             new.column_states = self.column_states
             new.pre_actions = new.from_.pre_actions

src/snowflake/snowpark/mock/_select_statement.py

@@ -521,7 +521,7 @@ def set_operator(
     def limit(self, n: int, *, offset: int = 0) -> "SelectStatement":
         new = copy(self)
         new.from_ = self.from_.to_subqueryable()
-        new.limit_ = min(self.limit_, n) if self.limit_ else n
+        new.limit_ = min(self.limit_, n) if self.limit_ is not None else n
         new.offset = (self.offset + offset) if self.offset else offset
         new._column_states = self._column_states
         return new

tests/ast/data/df_limit.test

@@ -6,6 +6,8 @@ df = df.select(col("*")).limit(3)
 
 df = df.select(col("*")).limit(n=1, offset=1)
 
+df = df.select(col("*")).limit(0)
+
 ## EXPECTED UNPARSER OUTPUT
 
 df = session.table("table1")
@@ -18,6 +20,10 @@ df = df.select(col("*"))
 
 df = df.limit(1, 1)
 
+df = df.select(col("*"))
+
+df = df.limit(0, 0)
+
 ## EXPECTED ENCODED AST
 
 interned_value_table {
@@ -254,6 +260,101 @@ body {
     }
   }
 }
+body {
+  assign {
+    expr {
+      dataframe_select__columns {
+        cols {
+          args {
+            apply_expr {
+              fn {
+                builtin_fn {
+                  name {
+                    name {
+                      name_flat {
+                        name: "col"
+                      }
+                    }
+                  }
+                }
+              }
+              pos_args {
+                string_val {
+                  src {
+                    end_column: 31
+                    end_line: 31
+                    file: 2
+                    start_column: 23
+                    start_line: 31
+                  }
+                  v: "*"
+                }
+              }
+              src {
+                end_column: 31
+                end_line: 31
+                file: 2
+                start_column: 23
+                start_line: 31
+              }
+            }
+          }
+          variadic: true
+        }
+        df {
+          dataframe_ref {
+            id {
+              bitfield1: 5
+            }
+          }
+        }
+        src {
+          end_column: 32
+          end_line: 31
+          file: 2
+          start_column: 13
+          start_line: 31
+        }
+      }
+    }
+    symbol {
+      value: "df"
+    }
+    uid: 6
+    var_id {
+      bitfield1: 6
+    }
+  }
+}
+body {
+  assign {
+    expr {
+      dataframe_limit {
+        df {
+          dataframe_ref {
+            id {
+              bitfield1: 6
+            }
+          }
+        }
+        src {
+          end_column: 41
+          end_line: 31
+          file: 2
+          start_column: 13
+          start_line: 31
+        }
+      }
+    }
+    symbol {
+      value: "df"
+    }
+    uid: 7
+    var_id {
+      bitfield1: 7
+    }
+  }
+}
 client_ast_version: 1
 client_language {
   python_language {

tests/integ/scala/test_dataframe_suite.py

@@ -3180,3 +3180,44 @@ def test_to_df(session):
     assert "Invalid input type in to_df(), expected str or a list of strs." in str(
         exc_info
     )
+
+
+def test_limit(session):
+    df = session.create_dataframe([[1, 2], [2, 3]]).to_df("a", "b")
+    # run show(), make sure no error is reported
+    res = df._show_string(_emit_ast=session.ast_enabled)
+    assert (
+        res
+        == """
+-------------
+|"A"  |"B"  |
+-------------
+|1    |2    |
+|2    |3    |
+-------------\n""".lstrip()
+    )
+
+    df1 = df.limit(1)
+    res = df1._show_string(_emit_ast=session.ast_enabled)
+    assert (
+        res
+        == """
+-------------
+|"A"  |"B"  |
+-------------
+|1    |2    |
+-------------\n""".lstrip()
+    )
+
+    df2 = df.limit(0)
+
+    res = df2._show_string(_emit_ast=session.ast_enabled)
+    assert (
+        res
+        == """
+-------------
+|"A"  |"B"  |
+-------------
+|     |     |
+-------------\n""".lstrip()
+    )

tests/integ/test_simplifier_suite.py

@@ -825,15 +825,25 @@ def test_filter(setup_reduce_cast, session, simplifier_table):
 def test_limit(setup_reduce_cast, session, simplifier_table):
     df = session.table(simplifier_table)
     df = df.limit(10)
-    assert df.queries["queries"][-1] == f"SELECT  *  FROM {simplifier_table} LIMIT 10"
+    assert (
+        df.queries["queries"][-1].lower()
+        == f"select  *  from {simplifier_table.lower()} limit 10"
+    )
 
     df = session.sql(f"select * from {simplifier_table}")
     df = df.limit(10)
     # we don't know if the original sql already has top/limit clause using a subquery is necessary.
     #  or else there will be SQL compile error.
     assert (
-        df.queries["queries"][-1]
-        == f"SELECT  *  FROM (select * from {simplifier_table}) LIMIT 10"
+        df.queries["queries"][-1].lower()
+        == f"select  *  from (select * from {simplifier_table.lower()}) limit 10"
+    )
+
+    df = session.sql(f"select * from {simplifier_table}")
+    df = df.limit(0)
+    assert (
+        df.queries["queries"][-1].lower()
+        == f"select  *  from (select * from {simplifier_table.lower()}) limit 0"
     )
 
     # test for non-select sql statement