New Rule L056: 'SP_' prefix should not be used for user-defined store…

…d procedures (#1930)

* New Rule L056: 'SP_' prefix should not be used for user-defined stored procedures in T-SQL.

* Add extra test cases for bracketed/quoted stored procedure names

* Fix unescaped underscores in L056 docstring

* raw docstrings to satisfy flake8 + sphinx

* Remove unnecessary lists

* Use description param of LintResult to avoid escape backslash in docstring from showing during linting

* Black reformat

Co-authored-by: Barry Pollard <barry@tunetheweb.com>

src/sqlfluff/rules/L056.py

@@ -0,0 +1,78 @@
+"""Implementation of Rule L056."""
+from typing import Optional
+
+from sqlfluff.core.rules.base import BaseRule, LintResult, RuleContext
+
+
+class Rule_L056(BaseRule):
+    r"""'SP\_' prefix should not be used for user-defined stored procedures in T-SQL.
+
+    | **Anti-pattern**
+    | The 'SP\_' prefix is used to identify system procedures and
+    | can adversely affect performance of the user-defined stored procedure.
+    | It can also break system procedures if there is a naming conflict.
+
+    .. code-block:: sql
+       :force:
+
+        CREATE PROCEDURE dbo.sp_pull_data
+        AS
+        SELECT
+            ID,
+            DataDate,
+            CaseOutput
+        FROM table1
+
+    | **Best practice**
+    | Use a different name for the stored procedure.
+
+    .. code-block:: sql
+       :force:
+
+        CREATE PROCEDURE dbo.pull_data
+        AS
+        SELECT
+            ID,
+            DataDate,
+            CaseOutput
+        FROM table1
+
+        -- Alternatively prefix with 'USP_' to
+        -- indicate a user-defined stored procedure.
+
+        CREATE PROCEDURE dbo.usp_pull_data
+        AS
+        SELECT
+            ID,
+            DataDate,
+            CaseOutput
+        FROM table1
+    """
+
+    def _eval(self, context: RuleContext) -> Optional[LintResult]:
+        r"""'SP\_' prefix should not be used for user-defined stored procedures."""
+        # Rule only applies to T-SQL syntax.
+        if context.dialect.name != "tsql":
+            return None
+
+        # We are only interested in CREATE PROCEDURE statements.
+        if context.segment.type != "create_procedure_statement":
+            return None
+
+        # Find the object reference for the stored procedure.
+        object_reference_segment = next(
+            (s for s in context.segment.segments if s.type == "object_reference")
+        )
+
+        # We only want to check the stored procedure name.
+        procedure_segment = object_reference_segment.segments[-1]
+
+        # If stored procedure name starts with 'SP\_' then raise lint error.
+        if procedure_segment.raw_upper.lstrip('["').startswith("SP_"):
+            "s".lstrip
+            return LintResult(
+                procedure_segment,
+                description="'SP_' prefix should not be used for user-defined stored procedures.",
+            )
+
+        return None

test/fixtures/rules/std_rule_cases/L056.yml

@@ -0,0 +1,92 @@
+rule: L056
+
+test_fail_sp_prefix_1:
+  fail_str: |
+    CREATE PROCEDURE dbo.sp_pull_data
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_fail_sp_prefix_2:
+  fail_str: |
+    CREATE PROCEDURE dbo.[sp_pull_data]
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_fail_sp_prefix_3:
+  fail_str: |
+    CREATE PROCEDURE dbo."sp_pull_data"
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_pass_non_sp_prefix_1:
+  pass_str: |
+    CREATE PROCEDURE dbo.pull_data
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_pass_non_sp_prefix_2:
+  pass_str: |
+    CREATE PROCEDURE dbo.usp_pull_data
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_pass_non_sp_prefix_3:
+  pass_str: |
+    CREATE PROCEDURE dbo.[usp_pull_data]
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql
+
+test_pass_non_sp_prefix_4:
+  pass_str: |
+    CREATE PROCEDURE dbo."usp_pull_data"
+    AS
+    SELECT
+        ID,
+        DataDate,
+        CaseOutput
+    FROM table1
+  configs:
+    core:
+      dialect: tsql