From 5f9f567acbc58c9fcd88af440e68034510fb5d2b Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Mon, 26 Sep 2022 16:06:01 -0700
Subject: [PATCH] Show SQL query when reporting time limit error, closes #1819

---
 datasette/database.py   |  5 ++++-
 datasette/views/base.py | 21 +++++++++++++--------
 tests/test_api.py       | 12 +++++++++++-
 tests/test_html.py      | 10 +++++++---
 4 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/datasette/database.py b/datasette/database.py
index 44467370..46094bd7 100644
--- a/datasette/database.py
+++ b/datasette/database.py
@@ -476,7 +476,10 @@ class WriteTask:
 
 
 class QueryInterrupted(Exception):
-    pass
+    def __init__(self, e, sql, params):
+        self.e = e
+        self.sql = sql
+        self.params = params
 
 
 class MultipleValues(Exception):
diff --git a/datasette/views/base.py b/datasette/views/base.py
index 221e1882..67aa3a42 100644
--- a/datasette/views/base.py
+++ b/datasette/views/base.py
@@ -1,10 +1,12 @@
 import asyncio
 import csv
 import hashlib
-import re
 import sys
+import textwrap
 import time
 import urllib
+from markupsafe import escape
+
 
 import pint
 
@@ -24,11 +26,9 @@ from datasette.utils import (
     path_with_removed_args,
     path_with_format,
     sqlite3,
-    HASH_LENGTH,
 )
 from datasette.utils.asgi import (
     AsgiStream,
-    Forbidden,
     NotFound,
     Response,
     BadRequest,
@@ -371,13 +371,18 @@ class DataView(BaseView):
                 ) = response_or_template_contexts
             else:
                 data, extra_template_data, templates = response_or_template_contexts
-        except QueryInterrupted:
+        except QueryInterrupted as ex:
             raise DatasetteError(
-                """
-                SQL query took too long. The time limit is controlled by the
+                textwrap.dedent(
+                    """
+                <p>SQL query took too long. The time limit is controlled by the
                 <a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>
-                configuration option.
-            """,
+                configuration option.</p>
+                <pre>{}</pre>
+            """.format(
+                        escape(ex.sql)
+                    )
+                ).strip(),
                 title="SQL Interrupted",
                 status=400,
                 message_is_html=True,
diff --git a/tests/test_api.py b/tests/test_api.py
index 7a2bf91f..ad74d16e 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -656,7 +656,17 @@ def test_custom_sql(app_client):
 def test_sql_time_limit(app_client_shorter_time_limit):
     response = app_client_shorter_time_limit.get("/fixtures.json?sql=select+sleep(0.5)")
     assert 400 == response.status
-    assert "SQL Interrupted" == response.json["title"]
+    assert response.json == {
+        "ok": False,
+        "error": (
+            "<p>SQL query took too long. The time limit is controlled by the\n"
+            '<a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>\n'
+            "configuration option.</p>\n"
+            "<pre>select sleep(0.5)</pre>"
+        ),
+        "status": 400,
+        "title": "SQL Interrupted",
+    }
 
 
 def test_custom_sql_time_limit(app_client):
diff --git a/tests/test_html.py b/tests/test_html.py
index bf915247..a99b0b6c 100644
--- a/tests/test_html.py
+++ b/tests/test_html.py
@@ -168,10 +168,14 @@ def test_disallowed_custom_sql_pragma(app_client):
 def test_sql_time_limit(app_client_shorter_time_limit):
     response = app_client_shorter_time_limit.get("/fixtures?sql=select+sleep(0.5)")
     assert 400 == response.status
-    expected_html_fragment = """
+    expected_html_fragments = [
+        """
         <a href="https://docs.datasette.io/en/stable/settings.html#sql-time-limit-ms">sql_time_limit_ms</a>
-    """.strip()
-    assert expected_html_fragment in response.text
+    """.strip(),
+        "<pre>select sleep(0.5)</pre>",
+    ]
+    for expected_html_fragment in expected_html_fragments:
+        assert expected_html_fragment in response.text
 
 
 def test_row_page_does_not_truncate():