From dfbcbcce67e808cfe36a1c554532a8d36e205812 Mon Sep 17 00:00:00 2001
From: "Hugh A. Miles II" <hughmil3s@gmail.com>
Date: Wed, 21 Oct 2020 12:58:57 -0700
Subject: [PATCH] fix: Allow "EXPLAIN" queries when "Allow DML" setting is
 False (#11348)

Co-authored-by: Beto Dealmeida <roberto@dealmeida.net>
---
 superset/sql_parse.py    |  8 ++++++-
 tests/sql_parse_tests.py | 48 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/superset/sql_parse.py b/superset/sql_parse.py
index 0bc20c1bf..9690c9fd8 100644
--- a/superset/sql_parse.py
+++ b/superset/sql_parse.py
@@ -111,7 +111,13 @@ class ParsedQuery:
         return self._parsed[0].get_type() == "SELECT"
 
     def is_explain(self) -> bool:
-        return self.stripped().upper().startswith("EXPLAIN")
+        # Remove comments
+        statements_without_comments = sqlparse.format(
+            self.stripped(), strip_comments=True
+        )
+
+        # Explain statements will only be the first statement
+        return statements_without_comments.startswith("EXPLAIN")
 
     def is_unknown(self) -> bool:
         return self._parsed[0].get_type() == "UNKNOWN"
diff --git a/tests/sql_parse_tests.py b/tests/sql_parse_tests.py
index f2ad795aa..0176bb6d1 100644
--- a/tests/sql_parse_tests.py
+++ b/tests/sql_parse_tests.py
@@ -579,3 +579,51 @@ class TestSupersetSqlParse(unittest.TestCase):
                 reindent=True,
             ),
         )
+
+    def test_is_explain(self):
+        query = """
+            -- comment
+            EXPLAIN select * from table
+            -- comment 2
+        """
+        parsed = ParsedQuery(query)
+        self.assertEqual(parsed.is_explain(), True)
+
+        query = """
+            -- comment
+            EXPLAIN select * from table
+            where col1 = 'something'
+            -- comment 2
+
+            -- comment 3
+            EXPLAIN select * from table
+            where col1 = 'something'
+            -- comment 4
+        """
+        parsed = ParsedQuery(query)
+        self.assertEqual(parsed.is_explain(), True)
+
+        query = """
+            -- This is a comment
+                -- this is another comment but with a space in the front
+            EXPLAIN SELECT * FROM TABLE
+        """
+        parsed = ParsedQuery(query)
+        self.assertEqual(parsed.is_explain(), True)
+
+        query = """
+            /* This is a comment
+                 with stars instead */
+            EXPLAIN SELECT * FROM TABLE
+        """
+        parsed = ParsedQuery(query)
+        self.assertEqual(parsed.is_explain(), True)
+
+        query = """
+            -- comment
+            select * from table
+            where col1 = 'something'
+            -- comment 2
+        """
+        parsed = ParsedQuery(query)
+        self.assertEqual(parsed.is_explain(), False)