3 files changed, 24 insertions, 13 deletions
diff --git a/pgcli/packages/parseutils/__init__.py b/pgcli/packages/parseutils/__init__.py
index a11e7bf..1acc008 100644
--- a/pgcli/packages/parseutils/__init__.py
+++ b/pgcli/packages/parseutils/__init__.py
@@ -1,22 +1,34 @@
 import sqlparse
 
 
-def query_starts_with(query, prefixes):
+def query_starts_with(formatted_sql, prefixes):
     """Check if the query starts with any item from *prefixes*."""
     prefixes = [prefix.lower() for prefix in prefixes]
-    formatted_sql = sqlparse.format(query.lower(), strip_comments=True).strip()
     return bool(formatted_sql) and formatted_sql.split()[0] in prefixes
 
 
-def queries_start_with(queries, prefixes):
-    """Check if any queries start with any item from *prefixes*."""
-    for query in sqlparse.split(queries):
-        if query and query_starts_with(query, prefixes) is True:
-            return True
-    return False
+def query_is_unconditional_update(formatted_sql):
+    """Check if the query starts with UPDATE and contains no WHERE."""
+    tokens = formatted_sql.split()
+    return bool(tokens) and tokens[0] == "update" and "where" not in tokens
+
 
+def query_is_simple_update(formatted_sql):
+    """Check if the query starts with UPDATE."""
+    tokens = formatted_sql.split()
+    return bool(tokens) and tokens[0] == "update"
 
-def is_destructive(queries):
+
+def is_destructive(queries, warning_level="all"):
     """Returns if any of the queries in *queries* is destructive."""
     keywords = ("drop", "shutdown", "delete", "truncate", "alter")
-    return queries_start_with(queries, keywords)
+    for query in sqlparse.split(queries):
+        if query:
+            formatted_sql = sqlparse.format(query.lower(), strip_comments=True).strip()
+            if query_starts_with(formatted_sql, keywords):
+                return True
+            if query_is_unconditional_update(formatted_sql):
+                return True
+            if warning_level == "all" and query_is_simple_update(formatted_sql):
+                return True
+    return False
diff --git a/pgcli/packages/parseutils/meta.py b/pgcli/packages/parseutils/meta.py
index 108c01a..333cab5 100644
--- a/pgcli/packages/parseutils/meta.py
+++ b/pgcli/packages/parseutils/meta.py
@@ -50,7 +50,7 @@ def parse_defaults(defaults_string):
     yield current
 
 
-class FunctionMetadata(object):
+class FunctionMetadata:
     def __init__(
         self,
         schema_name,
diff --git a/pgcli/packages/parseutils/tables.py b/pgcli/packages/parseutils/tables.py
index 0ec3e69..aaa676c 100644
--- a/pgcli/packages/parseutils/tables.py
+++ b/pgcli/packages/parseutils/tables.py
@@ -42,8 +42,7 @@ def extract_from_part(parsed, stop_at_punctuation=True):
     for item in parsed.tokens:
         if tbl_prefix_seen:
             if is_subselect(item):
-                for x in extract_from_part(item, stop_at_punctuation):
-                    yield x
+                yield from extract_from_part(item, stop_at_punctuation)
             elif stop_at_punctuation and item.ttype is Punctuation:
                 return
             # An incomplete nested select won't be recognized correctly as a