[pydocstyle] Escaped docstring in docstring (D301 )

crates/ruff_linter/resources/test/fixtures/pydocstyle/D301.py

@@ -35,3 +35,61 @@ def make_unique_pod_id(pod_id: str) -> str | None:
 
 def shouldnt_add_raw_here2():
     u"Sum\\mary."
+
+
+def shouldnt_add_raw_for_double_quote_docstring_contains_docstring():
+    """
+    This docstring contains another double-quote docstring.
+
+        def foo():
+            \"\"\"Foo.\"\"\"
+    """
+
+
+def shouldnt_add_raw_for_double_quote_docstring_contains_docstring2():
+    """
+    This docstring contains another double-quote docstring.
+
+        def bar():
+            \"""Bar.\"""
+    """
+
+
+def shouldnt_add_raw_for_single_quote_docstring_contains_docstring():
+    '''
+    This docstring contains another single-quote docstring.
+
+        def foo():
+            \'\'\'Foo.\'\'\'
+    '''
+
+
+def shouldnt_add_raw_for_single_quote_docstring_contains_docstring2():
+    '''
+    This docstring contains another single-quote docstring.
+
+        def bar():
+            \'''Bar.\'''
+    '''
+
+def shouldnt_add_raw_for_docstring_contains_escaped_double_triple_quotes():
+    """
+    Escaped triple quote \""" or \"\"\".
+    """
+
+def shouldnt_add_raw_for_docstring_contains_escaped_single_triple_quotes():
+    '''
+    Escaped triple quote \''' or \'\'\'.
+    '''
+
+
+def should_add_raw_for_single_double_quote_escape():
+    """
+    This is single quote escape \".
+    """
+
+
+def should_add_raw_for_single_single_quote_escape():
+    '''
+    This is single quote escape \'.
+    '''

crates/ruff_linter/src/rules/pydocstyle/rules/backslashes.rs

@@ -69,8 +69,39 @@ pub(crate) fn backslashes(checker: &mut Checker, docstring: &Docstring) {
     // Docstring contains at least one backslash.
     let body = docstring.body();
     let bytes = body.as_bytes();
+    let mut backslash_index = 0;
+    let double_quote_docstring_backslashes_pattern = b"\"\\\"\\\"";
+    let single_quote_docstring_backslashes_pattern = b"\'\\\'\\\'";
     if memchr_iter(b'\\', bytes).any(|position| {
         let escaped_char = bytes.get(position.saturating_add(1));
+        // Allow escaped docstring.
+        if matches!(escaped_char, Some(b'"' | b'\'')) {
+            // If the next three characters are equal to """, it indicates an escaped docstring pattern.
+            let escaped_triple_quotes =
+                &bytes[position.saturating_add(1)..position.saturating_add(4)];
+            if escaped_triple_quotes == b"\"\"\"" || escaped_triple_quotes == b"\'\'\'" {
+                return false;
+            }
+
+            // For the `"\"\"` pattern, each iteration advances by 2 characters.
+            // For example, the sequence progresses from `"\"\"` to `"\"` and then to `"`.
+            // Therefore, we utilize an index to keep track of the remaining characters.
+            let escaped_quotes_backslashes = &bytes
+                [position.saturating_add(1)..position.saturating_add(6 - backslash_index * 2)];
+            if escaped_quotes_backslashes
+                == &double_quote_docstring_backslashes_pattern[backslash_index * 2..]
+                || escaped_quotes_backslashes
+                    == &single_quote_docstring_backslashes_pattern[backslash_index * 2..]
+            {
+                backslash_index += 1;
+                // Reset to avoid overflow.
+                if backslash_index > 2 {
+                    backslash_index = 0;
+                }
+                return false;
+            }
+            return true;
+        }
         // Allow continuations (backslashes followed by newlines) and Unicode escapes.
         !matches!(escaped_char, Some(b'\r' | b'\n' | b'u' | b'U' | b'N'))
     }) {

crates/ruff_linter/src/rules/pydocstyle/snapshots/ruff_linter__rules__pydocstyle__tests__D301_D301.py.snap

@@ -25,4 +25,43 @@ D301.py:37:5: D301 Use `r"""` if any backslashes in a docstring
    |
    = help: Add `r` prefix
 
+D301.py:87:5: D301 [*] Use `r"""` if any backslashes in a docstring
+   |
+86 |   def should_add_raw_for_single_double_quote_escape():
+87 |       """
+   |  _____^
+88 | |     This is single quote escape \".
+89 | |     """
+   | |_______^ D301
+   |
+   = help: Add `r` prefix
+
+ℹ Unsafe fix
+84 84 | 
+85 85 | 
+86 86 | def should_add_raw_for_single_double_quote_escape():
+87    |-    """
+   87 |+    r"""
+88 88 |     This is single quote escape \".
+89 89 |     """
+90 90 | 
 
+D301.py:93:5: D301 [*] Use `r"""` if any backslashes in a docstring
+   |
+92 |   def should_add_raw_for_single_single_quote_escape():
+93 |       '''
+   |  _____^
+94 | |     This is single quote escape \'.
+95 | |     '''
+   | |_______^ D301
+   |
+   = help: Add `r` prefix
+
+ℹ Unsafe fix
+90 90 | 
+91 91 | 
+92 92 | def should_add_raw_for_single_single_quote_escape():
+93    |-    '''
+   93 |+    r'''
+94 94 |     This is single quote escape \'.
+95 95 |     '''