From ee16edc4b74a0a9c33249d9d333716e50350900e Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Tue, 10 Oct 2023 12:20:46 -0400
Subject: [PATCH] Avoid converting f-strings within Django gettext calls

---
 .../test/fixtures/pyupgrade/UP032_3.py        |  9 +++++++++
 crates/ruff_linter/src/rules/pyupgrade/mod.rs |  1 +
 .../src/rules/pyupgrade/rules/f_strings.rs    | 20 +++++++++++++++++++
 ...__rules__pyupgrade__tests__UP032_3.py.snap |  4 ++++
 4 files changed, 34 insertions(+)
 create mode 100644 crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_3.py
 create mode 100644 crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_3.py.snap

diff --git a/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_3.py b/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_3.py
new file mode 100644
index 0000000000000..9c32a1a3e27a3
--- /dev/null
+++ b/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_3.py
@@ -0,0 +1,9 @@
+from django.utils.translation import gettext
+
+long = 'long'
+split_to = 'split_to'
+gettext(
+    'some super {} and complicated string so that the error code '
+    'E501 Triggers when this is not {} multi-line'.format(
+        long, split_to)
+)
diff --git a/crates/ruff_linter/src/rules/pyupgrade/mod.rs b/crates/ruff_linter/src/rules/pyupgrade/mod.rs
index 54181e3e085c5..d9ba5d890a2ba 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/mod.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/mod.rs
@@ -28,6 +28,7 @@ mod tests {
     #[test_case(Rule::FString, Path::new("UP032_0.py"))]
     #[test_case(Rule::FString, Path::new("UP032_1.py"))]
     #[test_case(Rule::FString, Path::new("UP032_2.py"))]
+    #[test_case(Rule::FString, Path::new("UP032_3.py"))]
     #[test_case(Rule::FormatLiterals, Path::new("UP030_0.py"))]
     #[test_case(Rule::FormatLiterals, Path::new("UP030_1.py"))]
     #[test_case(Rule::LRUCacheWithMaxsizeNone, Path::new("UP033_0.py"))]
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs
index 6b3ca300d4c3e..10783a0495e43 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs
@@ -328,6 +328,7 @@ pub(crate) fn f_strings(
     let Some(mut summary) = FormatSummaryValues::try_from_call(call, checker.locator()) else {
         return;
     };
+
     let mut patches: Vec<(TextRange, String)> = vec![];
     let mut lex = lexer::lex_starts_at(
         checker.locator().slice(call.func.range()),
@@ -405,6 +406,25 @@ pub(crate) fn f_strings(
         return;
     }
 
+    // Finally, avoid refactors that would introduce a runtime error.
+    // For example, Django's `gettext` supports `format`-style arguments, but not f-strings.
+    // See: https://docs.djangoproject.com/en/4.2/topics/i18n/translation
+    if checker.semantic().current_expressions().any(|expr| {
+        expr.as_call_expr().is_some_and(|call| {
+            checker
+                .semantic()
+                .resolve_call_path(call.func.as_ref())
+                .map_or(false, |call_path| {
+                    matches!(
+                        call_path.as_slice(),
+                        ["django", "utils", "translation", "gettext" | "gettext_lazy"]
+                    )
+                })
+        })
+    }) {
+        return;
+    }
+
     let mut diagnostic = Diagnostic::new(FString, call.range());
 
     // Avoid fix if there are comments within the call:
diff --git a/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_3.py.snap b/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_3.py.snap
new file mode 100644
index 0000000000000..2bacb5d540775
--- /dev/null
+++ b/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_3.py.snap
@@ -0,0 +1,4 @@
+---
+source: crates/ruff_linter/src/rules/pyupgrade/mod.rs
+---
+