Allowed low ranking search results to be returned in doc search.

This also indicates to the user that they can use the PostgreSQL
websearch_to_tsquery syntax.

Author: sarahboyce

djangoproject/scss/_style.scss

@@ -2763,7 +2763,7 @@ form {
         display: block;
         font-weight: 400;
         height: 30px;
-        margin: 10px 0px;
+        margin: 10px 0px 5px;
         padding: 6px 14% 8px 10px;
         text-indent: 0;
         vertical-align: middle;
@@ -2925,7 +2925,13 @@ form {
         margin: 0 0 10px 0;
 
         button {
-            top: 19%;
+            top: 13%;
+        }
+
+        .helptext {
+            font-size: 1.1rem;
+            line-height: 1.5rem;
+            display: block;
         }
     }
 }

docs/models.py

@@ -2,6 +2,7 @@
 import html
 import json
 import operator
+import re
 from functools import reduce
 from pathlib import Path
 
@@ -251,6 +252,13 @@ def search(self, query_text, release):
             )
             search_rank = SearchRank(models.F("search"), search_query)
             similarity = TrigramSimilarity("title", query_text)
+            search_filter = Q(rank__gt=0.3)
+            # Check if query_text contains PostgreSQL websearch_to_tsquery syntax.
+            # Specifically, phrases in double quotes or negation using -.
+            if bool(re.search(r'"[^"]+"| -\w+', query_text)):
+                # Filter by search_query only. This returns an accurate result set not
+                # impacted by "fuzzy" search additions.
+                search_filter = Q(search=search_query)
             return (
                 self.prefetch_related(
                     Prefetch(
@@ -261,12 +269,9 @@ def search(self, query_text, release):
                         "release__release", queryset=Release.objects.only("version")
                     ),
                 )
-                .filter(
-                    release_id=release.id,
-                    search=search_query,
-                )
+                .alias(rank=search_rank + similarity)
+                .filter(Q(release_id=release.id) & search_filter)
                 .annotate(
-                    rank=search_rank + similarity,
                     headline=SearchHeadline(
                         "title",
                         search_query,

docs/templates/docs/search_form.html

@@ -8,4 +8,9 @@
     <i class="icon icon-search"></i>
     <span class="visuallyhidden">{% trans 'Search' %}</span>
   </button>
+  <span class="helptext quiet">
+    {% blocktranslate trimmed %}
+      Uses PostgreSQL <code>websearch_to_tsquery</code> syntax e.g. use "quoted text" for a phrase.
+    {% endblocktranslate %}
+  </span>
 </form>

docs/tests.py

@@ -548,18 +548,16 @@ def setUp(self):
     def test_search(self):
         expected_list = [
             (
-                0.96982837,
                 "releases/1.2.1",
-                "<mark>Django</mark> 1.2.1 release notes",
+                "<mark>Django</mark> 1.2.1 release notes",  # Ranked: 0.96982837.
                 (
                     "<mark>Django</mark> 1.2.1 release notes ¶  \n "
                     "<mark>Django</mark> 1.2.1 was released almost immediately after 1.2.0 to correct two small"
                 ),
             ),
             (
-                0.9490876,
                 "releases/1.9.4",
-                "<mark>Django</mark> 1.9.4 release notes",
+                "<mark>Django</mark> 1.9.4 release notes",  # Ranked: 0.9490876.
                 (
                     "<mark>Django</mark> 1.9.4 release notes ¶  \n  "
                     "March 5, 2016  \n "
@@ -570,24 +568,24 @@ def test_search(self):
         self.assertQuerySetEqual(
             Document.objects.search("django", self.release),
             expected_list,
-            transform=attrgetter("rank", "path", "headline", "highlight"),
+            transform=attrgetter("path", "headline", "highlight"),
         )
 
     def test_websearch(self):
         self.assertQuerySetEqual(
             Document.objects.search('django "release notes" -packaging', self.release),
-            [("Django 1.9.4 release notes", 1.5675676)],
-            transform=attrgetter("title", "rank"),
+            ["Django 1.9.4 release notes"],
+            transform=attrgetter("title"),
         )
 
     def test_multilingual_search(self):
         self.assertQuerySetEqual(
             Document.objects.search("publication", self.release_fr),
             [
-                ("Notes de publication de Django 1.2.1", 1.0693262),
-                ("Notes de publication de Django 1.9.4", 1.0458658),
+                "Notes de publication de Django 1.2.1",  # Ranked: 1.0693262.
+                "Notes de publication de Django 1.9.4",  # Ranked: 1.0458658.
             ],
-            transform=attrgetter("title", "rank"),
+            transform=attrgetter("title"),
         )
 
     def test_empty_search(self):
@@ -642,6 +640,15 @@ def test_search_highlight_stemmed(self):
             transform=attrgetter("headline", "highlight"),
         )
 
+    def test_search_title(self):
+        misspelled_query = Document.objects.search("viewss", self.release)
+        with self.assertNumQueries(2):
+            self.assertQuerySetEqual(
+                misspelled_query,
+                ["Generic views"],
+                transform=attrgetter("headline"),
+            )
+
 
 class TemplateTestCase(TestCase):
     def _assertOGTitleEqual(self, doc, expected):