[pyupgrade] Write empty string in lieu of panic (#11696)

## Summary

Closes https://github.com/astral-sh/ruff/issues/11692.

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP032_0.py

@@ -259,3 +259,9 @@ raise ValueError(
 
 # 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)

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(
+        if contents.is_empty() {
-            contents,
+            // Ex) `''.format(self.project)`
-            call.range(),
+            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);
 }

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, but the string itself should remain.
     |
     = 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, but the string itself should remain.
+264 264 | ''.format(self.project)
+
+UP032_0.py:264:1: UP032 [*] Use f-string instead of `format` call
+    |
+263 | # The call should be removed, but the string itself should remain.
+264 | ''.format(self.project)
+    | ^^^^^^^^^^^^^^^^^^^^^^^ UP032
+265 | 
+266 | # The call should be removed, but the string itself should remain.
+    |
+    = help: Convert to f-string
+
+ℹ Safe fix
+261 261 | "{0} {1}".format(foo(), foo())
+262 262 | 
+263 263 | # The call should be removed, but the string itself should remain.
+264     |-''.format(self.project)
+    264 |+''
+265 265 | 
+266 266 | # The call should be removed, but the string itself should remain.
+267 267 | "".format(self.project)
+
+UP032_0.py:267:1: UP032 [*] Use f-string instead of `format` call
+    |
+266 | # The call should be removed, but the string itself should remain.
+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, but the string itself should remain.
+267     |-"".format(self.project)
+    267 |+""