gh-112364: Correct unparsing of backslashes and quotes in ast.unparse (#115696)

1 files changed, 8 insertions, 7 deletions

diff --git a/Lib/ast.py b/Lib/ast.py
index 43703a8..b8c4ce6 100644
--- a/Lib/ast.py
+++ b/Lib/ast.py
@@ -1269,14 +1269,18 @@ class _Unparser(NodeVisitor):
         quote_type = quote_types[0]
         self.write(f"{quote_type}{value}{quote_type}")
 
-    def _write_fstring_inner(self, node, escape_newlines=False):
+    def _write_fstring_inner(self, node, is_format_spec=False):
         if isinstance(node, JoinedStr):
             # for both the f-string itself, and format_spec
             for value in node.values:
-                self._write_fstring_inner(value, escape_newlines=escape_newlines)
+                self._write_fstring_inner(value, is_format_spec=is_format_spec)
         elif isinstance(node, Constant) and isinstance(node.value, str):
             value = node.value.replace("{", "{{").replace("}", "}}")
-            if escape_newlines:
+
+            if is_format_spec:
+                value = value.replace("\\", "\\\\")
+                value = value.replace("'", "\\'")
+                value = value.replace('"', '\\"')
                 value = value.replace("\n", "\\n")
             self.write(value)
         elif isinstance(node, FormattedValue):
@@ -1300,10 +1304,7 @@ class _Unparser(NodeVisitor):
                 self.write(f"!{chr(node.conversion)}")
             if node.format_spec:
                 self.write(":")
-                self._write_fstring_inner(
-                    node.format_spec,
-                    escape_newlines=True
-                )
+                self._write_fstring_inner(node.format_spec, is_format_spec=True)
 
     def visit_Name(self, node):
         self.write(node.id)