From dad006c28dca522bdc1fab418700d5ebf38b1e33 Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Sun, 2 Jun 2024 13:42:33 -0400
Subject: [PATCH] Write empty string in lieu of panic

---
 .../test/fixtures/pyupgrade/UP032_0.py        |  6 +++
 .../src/rules/pyupgrade/rules/f_strings.rs    | 18 ++++++---
 ...__rules__pyupgrade__tests__UP032_0.py.snap | 40 +++++++++++++++++++
 3 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_0.py b/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_0.py
index 09ea36db619430..497caa8d3c663c 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_0.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_0.py
@@ -259,3 +259,9 @@ async def c():
 
 # The string _should_ be converted, since the function call is repeated in the arguments.
 "{0} {1}".format(foo(), foo())
+
+# The call should be removed, but the string itself should remain.
+''.format(self.project)
+
+# The call should be removed, but the string itself should remain.
+"".format(self.project)
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 31a23832743495..d6441f9904490a 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/f_strings.rs
@@ -400,7 +400,7 @@ pub(crate) fn f_strings(checker: &mut Checker, call: &ast::ExprCall, summary: &F
         return;
     };
 
-    if !value.is_string_literal_expr() {
+    let Expr::StringLiteral(literal) = &**value else {
         return;
     };
 
@@ -520,10 +520,18 @@ pub(crate) fn f_strings(checker: &mut Checker, call: &ast::ExprCall, summary: &F
         .intersects(call.arguments.range());
 
     if !has_comments {
-        diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
-            contents,
-            call.range(),
-        )));
+        if contents.is_empty() {
+            // Ex) `''.format(self.project)`
+            diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                checker.locator().slice(literal).to_string(),
+                call.range(),
+            )));
+        } else {
+            diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                contents,
+                call.range(),
+            )));
+        }
     };
     checker.diagnostics.push(diagnostic);
 }
diff --git a/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_0.py.snap b/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_0.py.snap
index e5eb8940540144..6daaec300278e9 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_0.py.snap
+++ b/crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP032_0.py.snap
@@ -1321,6 +1321,8 @@ UP032_0.py:261:1: UP032 [*] Use f-string instead of `format` call
 260 | # The string _should_ be converted, since the function call is repeated in the arguments.
 261 | "{0} {1}".format(foo(), foo())
     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UP032
+262 | 
+263 | # The call should be removed.
     |
     = help: Convert to f-string
 
@@ -1330,3 +1332,41 @@ UP032_0.py:261:1: UP032 [*] Use f-string instead of `format` call
 260 260 | # The string _should_ be converted, since the function call is repeated in the arguments.
 261     |-"{0} {1}".format(foo(), foo())
     261 |+f"{foo()} {foo()}"
+262 262 | 
+263 263 | # The call should be removed.
+264 264 | ''.format(self.project)
+
+UP032_0.py:264:1: UP032 [*] Use f-string instead of `format` call
+    |
+263 | # The call should be removed.
+264 | ''.format(self.project)
+    | ^^^^^^^^^^^^^^^^^^^^^^^ UP032
+265 | 
+266 | # The call should be removed.
+    |
+    = help: Convert to f-string
+
+ℹ Safe fix
+261 261 | "{0} {1}".format(foo(), foo())
+262 262 | 
+263 263 | # The call should be removed.
+264     |-''.format(self.project)
+    264 |+''
+265 265 | 
+266 266 | # The call should be removed.
+267 267 | "".format(self.project)
+
+UP032_0.py:267:1: UP032 [*] Use f-string instead of `format` call
+    |
+266 | # The call should be removed.
+267 | "".format(self.project)
+    | ^^^^^^^^^^^^^^^^^^^^^^^ UP032
+    |
+    = help: Convert to f-string
+
+ℹ Safe fix
+264 264 | ''.format(self.project)
+265 265 | 
+266 266 | # The call should be removed.
+267     |-"".format(self.project)
+    267 |+""