python
diff --git a/‎Parser/lexer/state.c‎
Lines changed: 1 addition & 0 deletions b/‎Parser/lexer/state.c‎
Lines changed: 1 addition & 0 deletions
diff --git a/‎Parser/lexer/state.h‎
Lines changed: 1 addition & 1 deletion b/‎Parser/lexer/state.h‎
Lines changed: 1 addition & 1 deletion
diff --git a/‎Parser/lexer/string.c‎
Lines changed: 6 additions & 1 deletion b/‎Parser/lexer/string.c‎
Lines changed: 6 additions & 1 deletion
diff --git a/‎Parser/tokenizer/reader.c‎
Lines changed: 4 additions & 0 deletions b/‎Parser/tokenizer/reader.c‎
Lines changed: 4 additions & 0 deletions
@@ -9,6 +9,7 @@
 ftstring_state *
 _PyLexer_PushFTString(struct tok_state *tok)
 {
+    assert(tok->ftstring_depth >= 0 && tok->ftstring_depth <= tok->ftstring_capacity);
     int next_depth = tok->ftstring_depth + 1;
     if (next_depth >= MAXFTSTRINGLEVEL) {
         _PyTokenizer_syntaxerror(
 
@@ -115,7 +115,7 @@ static inline ftstring_state *
 _PyLexer_CurrentFTString(struct tok_state *tok)
 {
     assert(tok->ftstring_stack != NULL);
-    assert(tok->ftstring_depth <= tok->ftstring_capacity);
+    assert(tok->ftstring_depth >= 0 && tok->ftstring_depth <= tok->ftstring_capacity);
     if (tok->ftstring_depth == 0) {
         return NULL;
     }
 
@@ -20,6 +20,7 @@ int
 _PyLexer_record_ftstring_comment(struct tok_state *tok, ftstring_state *state,
                                  const char *start, const char *end)
 {
+    assert(state == _PyLexer_CurrentFTString(tok) && state->mode == FTSTRING_MODE_EXPRESSION);
     if (state->expr_span.end >= 0) {
         return 0;
     }
@@ -57,7 +58,8 @@ int
 _PyLexer_finish_ftstring_expr(struct tok_state *tok, ftstring_state *state,
                               struct token *token)
 {
-    assert(token != NULL);
+    assert(token != NULL && state == _PyLexer_CurrentFTString(tok));
+    assert(state->mode == FTSTRING_MODE_EXPRESSION && tok->start != NULL);
 
     if (state->expr_span.end >= 0) {
         return 0;
@@ -338,6 +340,9 @@ _PyLexer_scan_string(struct tok_state *tok, struct token *token, int c)
 int
 _PyLexer_get_ftstring(struct tok_state *tok, ftstring_state *current, struct token *token)
 {
+    assert(current == _PyLexer_CurrentFTString(tok) && current->mode != FTSTRING_MODE_EXPRESSION);
+    assert((current->quote_size == 1 || current->quote_size == 3) &&
+           current->replacement_depth <= MAX_EXPR_NESTING);
     const char *p_start = NULL;
     const char *p_end = NULL;
     int end_quote_size = 0;
 
@@ -169,6 +169,7 @@ append_implicit_newline(_PyTok_Reader *reader)
 static int
 pop_decoded_line(_PyTok_Reader *reader, _PyTok_Chunk *chunk)
 {
+    assert(reader->decoded_pos >= 0 && reader->decoded_pos <= reader->decoded_len);
     if (reader->decoded_pos == reader->decoded_len) {
         return 0;
     }
@@ -627,6 +628,8 @@ reset_streaming_buffer(struct tok_state *tok)
 int
 _PyTok_ReaderUnderflow(struct tok_state *tok)
 {
+    assert(tok->cur == tok->inp || (tok->buf != NULL &&
+           tok->cur >= tok->buf && tok->cur < tok->inp));
     _PyTok_ReaderKind kind = tok->reader->kind;
     int prepared = kind == _PYTOK_READER_PREPARED;
     int streaming = reader_is_streaming(kind);
@@ -660,6 +663,7 @@ _PyTok_ReaderUnderflow(struct tok_state *tok)
         }
         return 0;
     }
+    assert(chunk.data != NULL && chunk.len > 0);
     if (tok->lineno == INT_MAX) {
         PyErr_SetString(PyExc_OverflowError, "too many tokenizer source lines");
         tok->done = E_ERROR;
Original file line number	Diff line number	Diff line change
`@@ -9,6 +9,7 @@`
`9`	`9`	`ftstring_state *`
`10`	`10`	`_PyLexer_PushFTString(struct tok_state *tok)`
`11`	`11`	`{`
	`12`	`+ assert(tok->ftstring_depth >= 0 && tok->ftstring_depth <= tok->ftstring_capacity);`
`12`	`13`	`int next_depth = tok->ftstring_depth + 1;`
`13`	`14`	`if (next_depth >= MAXFTSTRINGLEVEL) {`
`14`	`15`	`_PyTokenizer_syntaxerror(`
Original file line number	Diff line number	Diff line change
`@@ -115,7 +115,7 @@ static inline ftstring_state *`
`115`	`115`	`_PyLexer_CurrentFTString(struct tok_state *tok)`
`116`	`116`	`{`
`117`	`117`	`assert(tok->ftstring_stack != NULL);`
`118`		`- assert(tok->ftstring_depth <= tok->ftstring_capacity);`
	`118`	`+ assert(tok->ftstring_depth >= 0 && tok->ftstring_depth <= tok->ftstring_capacity);`
`119`	`119`	`if (tok->ftstring_depth == 0) {`
`120`	`120`	`return NULL;`
`121`	`121`	`}`
Original file line number	Diff line number	Diff line change
`@@ -169,6 +169,7 @@ append_implicit_newline(_PyTok_Reader *reader)`
`169`	`169`	`static int`
`170`	`170`	`pop_decoded_line(_PyTok_Reader reader, _PyTok_Chunk chunk)`
`171`	`171`	`{`
	`172`	`+ assert(reader->decoded_pos >= 0 && reader->decoded_pos <= reader->decoded_len);`
`172`	`173`	`if (reader->decoded_pos == reader->decoded_len) {`
`173`	`174`	`return 0;`
`174`	`175`	`}`
`@@ -627,6 +628,8 @@ reset_streaming_buffer(struct tok_state *tok)`
`627`	`628`	`int`
`628`	`629`	`_PyTok_ReaderUnderflow(struct tok_state *tok)`
`629`	`630`	`{`
	`631`	`+ assert(tok->cur == tok->inp \|\| (tok->buf != NULL &&`
	`632`	`+ tok->cur >= tok->buf && tok->cur < tok->inp));`
`630`	`633`	`_PyTok_ReaderKind kind = tok->reader->kind;`
`631`	`634`	`int prepared = kind == _PYTOK_READER_PREPARED;`
`632`	`635`	`int streaming = reader_is_streaming(kind);`
`@@ -660,6 +663,7 @@ _PyTok_ReaderUnderflow(struct tok_state *tok)`
`660`	`663`	`}`
`661`	`664`	`return 0;`
`662`	`665`	`}`
	`666`	`+ assert(chunk.data != NULL && chunk.len > 0);`
`663`	`667`	`if (tok->lineno == INT_MAX) {`
`664`	`668`	`PyErr_SetString(PyExc_OverflowError, "too many tokenizer source lines");`
`665`	`669`	`tok->done = E_ERROR;`