From a43a797e34fe9e43d58ccf7fa736e39dca19a500 Mon Sep 17 00:00:00 2001
From: correctmost <134317971+correctmost@users.noreply.github.com>
Date: Sat, 15 Mar 2025 16:49:17 -0400
Subject: [PATCH 1/3] Speed up the generation of no-member suggestions

Previously, edit distances were calculated for strings that had
length differences greater than the maximum suggestion threshold.
---
 pylint/checkers/typecheck.py         | 22 ++++++++++++--
 tests/checkers/unittest_typecheck.py | 44 ++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index edef5188b4..6ff8044ff3 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -150,8 +150,12 @@ def _(node: nodes.ClassDef | bases.Instance) -> Iterable[str]:
     return itertools.chain(values, other_values)
 
 
-def _string_distance(seq1: str, seq2: str) -> int:
-    seq2_length = len(seq2)
+def _string_distance(seq1: str, seq2: str, seq1_length: int, seq2_length: int) -> int:
+    if not seq1_length:
+        return seq2_length
+
+    if not seq2_length:
+        return seq1_length
 
     row = [*list(range(1, seq2_length + 1)), 0]
     for seq1_index, seq1_char in enumerate(seq1):
@@ -179,14 +183,26 @@ def _similar_names(
     The similar names are searched given a distance metric and only
     a given number of choices will be returned.
     """
+    if max_choices <= 0:
+        return []
+
     possible_names: list[tuple[str, int]] = []
     names = _node_names(owner)
 
+    attr_str = attrname or ""
+    attr_len = len(attr_str)
+
     for name in names:
         if name == attrname:
             continue
 
-        distance = _string_distance(attrname or "", name)
+        name_len = len(name)
+
+        min_distance = abs(attr_len - name_len)
+        if min_distance > distance_threshold:
+            continue
+
+        distance = _string_distance(attr_str, name, attr_len, name_len)
         if distance <= distance_threshold:
             possible_names.append((name, distance))
 
diff --git a/tests/checkers/unittest_typecheck.py b/tests/checkers/unittest_typecheck.py
index c944b863f3..d3fd5a34c0 100644
--- a/tests/checkers/unittest_typecheck.py
+++ b/tests/checkers/unittest_typecheck.py
@@ -221,3 +221,47 @@ def decorated():
             )
         ):
             self.checker.visit_subscript(subscript)
+
+
+class TestTypeCheckerStringDistance:
+    """Tests for the _string_distance helper in pylint.checkers.typecheck."""
+
+    def test_string_distance_identical_strings(self) -> None:
+        seq1 = "hi"
+        seq2 = "hi"
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 0
+
+        seq1, seq2 = seq2, seq1
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 0
+
+    def test_string_distance_empty_string(self) -> None:
+        seq1 = ""
+        seq2 = "hi"
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 2
+
+        seq1, seq2 = seq2, seq1
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 2
+
+    def test_string_distance_edit_distance_one_character(self) -> None:
+        seq1 = "hi"
+        seq2 = "he"
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 1
+
+        seq1, seq2 = seq2, seq1
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 1
+
+    def test_string_distance_edit_distance_multiple_similar_characters(self) -> None:
+        seq1 = "hello"
+        seq2 = "yelps"
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 3
+
+        seq1, seq2 = seq2, seq1
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 3
+
+    def test_string_distance_edit_distance_all_dissimilar_characters(self) -> None:
+        seq1 = "yellow"
+        seq2 = "orange"
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 6
+
+        seq1, seq2 = seq2, seq1
+        assert typecheck._string_distance(seq1, seq2, len(seq1), len(seq2)) == 6

From c73bc96b5e38e2230fedea9ef034582261b8013b Mon Sep 17 00:00:00 2001
From: correctmost <134317971+correctmost@users.noreply.github.com>
Date: Sat, 15 Mar 2025 18:03:27 -0400
Subject: [PATCH 2/3] Remove handling of missing-member-hint-distance = 0

---
 pylint/checkers/typecheck.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index 6ff8044ff3..84ce54a629 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -183,9 +183,6 @@ def _similar_names(
     The similar names are searched given a distance metric and only
     a given number of choices will be returned.
     """
-    if max_choices <= 0:
-        return []
-
     possible_names: list[tuple[str, int]] = []
     names = _node_names(owner)
 

From ab593930c7ffe9b01f586f9c0fc5480da3309c4a Mon Sep 17 00:00:00 2001
From: Pierre Sassoulas <pierre.sassoulas@gmail.com>
Date: Tue, 25 Mar 2025 13:27:18 +0100
Subject: [PATCH 3/3] Add fragment

---
 doc/whatsnew/fragments/10277.other | 4 ++++
 1 file changed, 4 insertions(+)
 create mode 100644 doc/whatsnew/fragments/10277.other

diff --git a/doc/whatsnew/fragments/10277.other b/doc/whatsnew/fragments/10277.other
new file mode 100644
index 0000000000..a7a1bfb0b2
--- /dev/null
+++ b/doc/whatsnew/fragments/10277.other
@@ -0,0 +1,4 @@
+The algorithm used for ``no-member`` suggestions is now more efficient and cut the
+calculation when the distance score is already above the threshold.
+
+Refs #10277