From cdd491c72dc6875c291d4a451c1a748617f27e7a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cristi=C3=A1n=20Maureira-Fredes?=
 <Cristian.Maureira-Fredes@qt.io>
Date: Sun, 30 Apr 2023 01:51:20 +0200
Subject: [PATCH 1/2] gh-102856: Allow comments inside multi-line f-string
 expresions

---
 Lib/test/test_fstring.py | 34 ++++++++++++++++++++++++++++++++++
 Parser/tokenizer.c       |  4 +++-
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index 5e94c99ae65af1..9457e95e667545 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -653,6 +653,40 @@ def test_comments(self):
                             ["f'{)#}'",   # When wrapped in parens, this becomes
                                           #  '()#)'.  Make sure that doesn't compile.
                              ])
+        self.assertEqual(f'''A complex trick: {
+2  # two
+}''', 'A complex trick: 2')
+        self.assertEqual(f'''
+{
+40 # fourty
++  # plus
+2  # two
+}''', '\n42')
+        self.assertEqual(f'''
+{
+40 # fourty
++  # plus
+2  # two
+}''', '\n42')
+
+        self.assertEqual(f'''
+# this is not a comment
+{ # the following operation it's
+3 # this is a number
+* 2}''', '\n# this is not a comment\n6')
+        self.assertEqual(f'''
+{# f'a {comment}'
+86 # constant
+# nothing more
+}''', '\n86')
+
+        self.assertAllRaise(SyntaxError, r"f-string: valid expression required before '}'",
+                            ["""f'''
+{
+# only a comment
+}'''
+""", # this is equivalent to f'{}'
+                             ])
 
     def test_many_expressions(self):
         # Create a string with many expressions in it. Note that
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 8de0572a1fc459..51ea86f5472bc3 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -1793,7 +1793,9 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
     /* Skip comment, unless it's a type comment */
     if (c == '#') {
 
-        if (INSIDE_FSTRING(tok)) {
+        // We don't allow # inside a one-line f-string expr,
+        // but we do in multi-line f-string expr
+        if (INSIDE_FSTRING(tok) && (tok->lineno == 1)) {
             return MAKE_TOKEN(syntaxerror(tok, "f-string expression part cannot include '#'"));
         }
 

From 59d5c3422f5957f2c25c7d269bbf076fa243c39e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cristi=C3=A1n=20Maureira-Fredes?=
 <Cristian.Maureira-Fredes@qt.io>
Date: Sun, 30 Apr 2023 01:51:20 +0200
Subject: [PATCH 2/2] gh-102856: Allow comments inside multi-line f-string
 expresions

---
 Lib/test/test_fstring.py | 7 ++++---
 Parser/tokenizer.c       | 6 ------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py
index 9457e95e667545..d035431ed32433 100644
--- a/Lib/test/test_fstring.py
+++ b/Lib/test/test_fstring.py
@@ -644,10 +644,11 @@ def test_comments(self):
         self.assertEqual(f'{"#"}', '#')
         self.assertEqual(f'{d["#"]}', 'hash')
 
-        self.assertAllRaise(SyntaxError, "f-string expression part cannot include '#'",
-                            ["f'{1#}'",   # error because the expression becomes "(1#)"
-                             "f'{3(#)}'",
+        self.assertAllRaise(SyntaxError, "'{' was never closed",
+                            ["f'{1#}'",   # error because everything after '#' is a comment
                              "f'{#}'",
+                             "f'one: {1#}'",
+                             "f'{1# one} {2 this is a comment still#}'",
                              ])
         self.assertAllRaise(SyntaxError, r"f-string: unmatched '\)'",
                             ["f'{)#}'",   # When wrapped in parens, this becomes
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 51ea86f5472bc3..3709807efd8927 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -1793,12 +1793,6 @@ tok_get_normal_mode(struct tok_state *tok, tokenizer_mode* current_tok, struct t
     /* Skip comment, unless it's a type comment */
     if (c == '#') {
 
-        // We don't allow # inside a one-line f-string expr,
-        // but we do in multi-line f-string expr
-        if (INSIDE_FSTRING(tok) && (tok->lineno == 1)) {
-            return MAKE_TOKEN(syntaxerror(tok, "f-string expression part cannot include '#'"));
-        }
-
         const char *prefix, *p, *type_start;
         int current_starting_col_offset;