From 3a0d45c85b46d26cdc40febaa871871f158ab513 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
Date: Sun, 16 Feb 2025 14:50:16 -0500
Subject: [PATCH] [`flake8-debugger`] Also flag `sys.breakpointhook` and
 `sys.__breakpointhook__` (`T100`) (#16191)

## Summary

Fixes #16189.

Only `sys.breakpointhook` is flagged by the upstream linter:

https://github.com/pylint-dev/pylint/blob/007a745c8619c2cbf59f829a8f09fc6afa6eb0f1/pylint/checkers/stdlib.py#L38

but I think it makes sense to flag
[`__breakpointhook__`](https://docs.python.org/3/library/sys.html#sys.__breakpointhook__)
too, as suggested in the issue because it
> contain[s] the original value of breakpointhook [...] in case [it
happens] to get replaced with broken or alternative objects.

## Test Plan

New T100 test cases
---
 .../test/fixtures/flake8_debugger/T100.py     | 18 +++++++
 .../rules/flake8_debugger/rules/debugger.rs   |  5 +-
 ..._flake8_debugger__tests__T100_T100.py.snap | 54 +++++++++++++++++++
 3 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/flake8_debugger/T100.py b/crates/ruff_linter/resources/test/fixtures/flake8_debugger/T100.py
index 8154f1a4cd..d876c575df 100644
--- a/crates/ruff_linter/resources/test/fixtures/flake8_debugger/T100.py
+++ b/crates/ruff_linter/resources/test/fixtures/flake8_debugger/T100.py
@@ -23,3 +23,21 @@ debugpy.listen(1234)
 enable_attach()
 break_into_debugger()
 wait_for_attach()
+
+
+# also flag `breakpointhook` from `sys` but obviously not `sys` itself. see
+# https://github.com/astral-sh/ruff/issues/16189
+import sys # ok
+
+def scope():
+    from sys import breakpointhook # error
+
+    breakpointhook() # error
+
+def scope():
+    from sys import __breakpointhook__ # error
+
+    __breakpointhook__() # error
+
+sys.breakpointhook() # error
+sys.__breakpointhook__() # error
diff --git a/crates/ruff_linter/src/rules/flake8_debugger/rules/debugger.rs b/crates/ruff_linter/src/rules/flake8_debugger/rules/debugger.rs
index 7477cfdc89..b216e69f5a 100644
--- a/crates/ruff_linter/src/rules/flake8_debugger/rules/debugger.rs
+++ b/crates/ruff_linter/src/rules/flake8_debugger/rules/debugger.rs
@@ -109,14 +109,15 @@ fn is_debugger_call(qualified_name: &QualifiedName) -> bool {
             | ["builtins" | "", "breakpoint"]
             | ["debugpy", "breakpoint" | "listen" | "wait_for_client"]
             | ["ptvsd", "break_into_debugger" | "wait_for_attach"]
+            | ["sys", "breakpointhook" | "__breakpointhook__"]
     )
 }
 
 fn is_debugger_import(qualified_name: &QualifiedName) -> bool {
     // Constructed by taking every pattern in `is_debugger_call`, removing the last element in
     // each pattern, and de-duplicating the values.
-    // As a special-case, we omit `builtins` to allow `import builtins`, which is far more general
-    // than (e.g.) `import celery.contrib.rdb`.
+    // As special-cases, we omit `builtins` and `sys` to allow `import builtins` and `import sys`
+    // which are far more general than (e.g.) `import celery.contrib.rdb`.
     matches!(
         qualified_name.segments(),
         ["pdb" | "pudb" | "ipdb" | "debugpy" | "ptvsd"]
diff --git a/crates/ruff_linter/src/rules/flake8_debugger/snapshots/ruff_linter__rules__flake8_debugger__tests__T100_T100.py.snap b/crates/ruff_linter/src/rules/flake8_debugger/snapshots/ruff_linter__rules__flake8_debugger__tests__T100_T100.py.snap
index 3b8f68333c..75baaa0379 100644
--- a/crates/ruff_linter/src/rules/flake8_debugger/snapshots/ruff_linter__rules__flake8_debugger__tests__T100_T100.py.snap
+++ b/crates/ruff_linter/src/rules/flake8_debugger/snapshots/ruff_linter__rules__flake8_debugger__tests__T100_T100.py.snap
@@ -183,3 +183,57 @@ T100.py:25:1: T100 Trace found: `ptvsd.wait_for_attach` used
 25 | wait_for_attach()
    | ^^^^^^^^^^^^^^^^^ T100
    |
+
+T100.py:33:5: T100 Import for `sys.breakpointhook` found
+   |
+32 | def scope():
+33 |     from sys import breakpointhook # error
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ T100
+34 |
+35 |     breakpointhook() # error
+   |
+
+T100.py:35:5: T100 Trace found: `sys.breakpointhook` used
+   |
+33 |     from sys import breakpointhook # error
+34 |
+35 |     breakpointhook() # error
+   |     ^^^^^^^^^^^^^^^^ T100
+36 |
+37 | def scope():
+   |
+
+T100.py:38:5: T100 Import for `sys.__breakpointhook__` found
+   |
+37 | def scope():
+38 |     from sys import __breakpointhook__ # error
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ T100
+39 |
+40 |     __breakpointhook__() # error
+   |
+
+T100.py:40:5: T100 Trace found: `sys.__breakpointhook__` used
+   |
+38 |     from sys import __breakpointhook__ # error
+39 |
+40 |     __breakpointhook__() # error
+   |     ^^^^^^^^^^^^^^^^^^^^ T100
+41 |
+42 | sys.breakpointhook() # error
+   |
+
+T100.py:42:1: T100 Trace found: `sys.breakpointhook` used
+   |
+40 |     __breakpointhook__() # error
+41 |
+42 | sys.breakpointhook() # error
+   | ^^^^^^^^^^^^^^^^^^^^ T100
+43 | sys.__breakpointhook__() # error
+   |
+
+T100.py:43:1: T100 Trace found: `sys.__breakpointhook__` used
+   |
+42 | sys.breakpointhook() # error
+43 | sys.__breakpointhook__() # error
+   | ^^^^^^^^^^^^^^^^^^^^^^^^ T100
+   |