bpo-40334: Fix error location upon parsing an invalid string literal (GH-19962)
When parsing a string with an invalid escape, the old parser used to
point to the beginning of the invalid string. This commit changes the new
parser to match that behaviour, since it's currently pointing to the
end of the string (or to be more precise, to the beginning of the next
token).
diff --git a/Parser/pegen/parse_string.c b/Parser/pegen/parse_string.c
index d96303d..ca4b733 100644
--- a/Parser/pegen/parse_string.c
+++ b/Parser/pegen/parse_string.c
@@ -12,7 +12,7 @@
// file (like "_PyPegen_raise_syntax_error").
static int
-warn_invalid_escape_sequence(Parser *p, unsigned char first_invalid_escape_char)
+warn_invalid_escape_sequence(Parser *p, unsigned char first_invalid_escape_char, Token *t)
{
PyObject *msg =
PyUnicode_FromFormat("invalid escape sequence \\%c", first_invalid_escape_char);
@@ -20,11 +20,16 @@
return -1;
}
if (PyErr_WarnExplicitObject(PyExc_DeprecationWarning, msg, p->tok->filename,
- p->tok->lineno, NULL, NULL) < 0) {
+ t->lineno, NULL, NULL) < 0) {
if (PyErr_ExceptionMatches(PyExc_DeprecationWarning)) {
/* Replace the DeprecationWarning exception with a SyntaxError
to get a more accurate error report */
PyErr_Clear();
+
+ /* This is needed, in order for the SyntaxError to point to the token t,
+ since _PyPegen_raise_error uses p->tokens[p->fill - 1] for the
+ error location, if p->known_err_token is not set. */
+ p->known_err_token = t;
RAISE_SYNTAX_ERROR("invalid escape sequence \\%c", first_invalid_escape_char);
}
Py_DECREF(msg);
@@ -47,7 +52,7 @@
}
static PyObject *
-decode_unicode_with_escapes(Parser *parser, const char *s, size_t len)
+decode_unicode_with_escapes(Parser *parser, const char *s, size_t len, Token *t)
{
PyObject *v, *u;
char *buf;
@@ -110,7 +115,7 @@
v = _PyUnicode_DecodeUnicodeEscape(s, len, NULL, &first_invalid_escape);
if (v != NULL && first_invalid_escape != NULL) {
- if (warn_invalid_escape_sequence(parser, *first_invalid_escape) < 0) {
+ if (warn_invalid_escape_sequence(parser, *first_invalid_escape, t) < 0) {
/* We have not decref u before because first_invalid_escape points
inside u. */
Py_XDECREF(u);
@@ -123,7 +128,7 @@
}
static PyObject *
-decode_bytes_with_escapes(Parser *p, const char *s, Py_ssize_t len)
+decode_bytes_with_escapes(Parser *p, const char *s, Py_ssize_t len, Token *t)
{
const char *first_invalid_escape;
PyObject *result = _PyBytes_DecodeEscape(s, len, NULL, &first_invalid_escape);
@@ -132,7 +137,7 @@
}
if (first_invalid_escape != NULL) {
- if (warn_invalid_escape_sequence(p, *first_invalid_escape) < 0) {
+ if (warn_invalid_escape_sequence(p, *first_invalid_escape, t) < 0) {
Py_DECREF(result);
return NULL;
}
@@ -146,9 +151,14 @@
If the string is an f-string, set *fstr and *fstrlen to the unparsed
string object. Return 0 if no errors occurred. */
int
-_PyPegen_parsestr(Parser *p, const char *s, int *bytesmode, int *rawmode, PyObject **result,
- const char **fstr, Py_ssize_t *fstrlen)
+_PyPegen_parsestr(Parser *p, int *bytesmode, int *rawmode, PyObject **result,
+ const char **fstr, Py_ssize_t *fstrlen, Token *t)
{
+ const char *s = PyBytes_AsString(t->bytes);
+ if (s == NULL) {
+ return -1;
+ }
+
size_t len;
int quote = Py_CHARMASK(*s);
int fmode = 0;
@@ -245,7 +255,7 @@
*result = PyBytes_FromStringAndSize(s, len);
}
else {
- *result = decode_bytes_with_escapes(p, s, len);
+ *result = decode_bytes_with_escapes(p, s, len, t);
}
}
else {
@@ -253,7 +263,7 @@
*result = PyUnicode_DecodeUTF8Stateful(s, len, NULL, NULL);
}
else {
- *result = decode_unicode_with_escapes(p, s, len);
+ *result = decode_unicode_with_escapes(p, s, len, t);
}
}
return *result == NULL ? -1 : 0;
@@ -637,7 +647,7 @@
*/
static int
fstring_find_literal(Parser *p, const char **str, const char *end, int raw,
- PyObject **literal, int recurse_lvl)
+ PyObject **literal, int recurse_lvl, Token *t)
{
/* Get any literal string. It ends when we hit an un-doubled left
brace (which isn't part of a unicode name escape such as
@@ -660,7 +670,7 @@
}
break;
}
- if (ch == '{' && warn_invalid_escape_sequence(p, ch) < 0) {
+ if (ch == '{' && warn_invalid_escape_sequence(p, ch, t) < 0) {
return -1;
}
}
@@ -704,7 +714,7 @@
NULL, NULL);
else
*literal = decode_unicode_with_escapes(p, literal_start,
- s - literal_start);
+ s - literal_start, t);
if (!*literal)
return -1;
}
@@ -1041,7 +1051,7 @@
assert(*literal == NULL && *expression == NULL);
/* Get any literal string. */
- result = fstring_find_literal(p, str, end, raw, literal, recurse_lvl);
+ result = fstring_find_literal(p, str, end, raw, literal, recurse_lvl, t);
if (result < 0)
goto error;
diff --git a/Parser/pegen/parse_string.h b/Parser/pegen/parse_string.h
index 4f2aa94..cd85bd5 100644
--- a/Parser/pegen/parse_string.h
+++ b/Parser/pegen/parse_string.h
@@ -34,8 +34,8 @@
} FstringParser;
void _PyPegen_FstringParser_Init(FstringParser *);
-int _PyPegen_parsestr(Parser *, const char *, int *, int *, PyObject **,
- const char **, Py_ssize_t *);
+int _PyPegen_parsestr(Parser *, int *, int *, PyObject **,
+ const char **, Py_ssize_t *, Token *);
int _PyPegen_FstringParser_ConcatFstring(Parser *, FstringParser *, const char **,
const char *, int, int, Token *, Token *,
Token *);
diff --git a/Parser/pegen/pegen.c b/Parser/pegen/pegen.c
index c311593..06af53b 100644
--- a/Parser/pegen/pegen.c
+++ b/Parser/pegen/pegen.c
@@ -383,7 +383,7 @@
PyObject *errstr = NULL;
PyObject *loc = NULL;
PyObject *tmp = NULL;
- Token *t = p->tokens[p->fill - 1];
+ Token *t = p->known_err_token != NULL ? p->known_err_token : p->tokens[p->fill - 1];
Py_ssize_t col_number = !with_col_number;
va_list va;
p->error_indicator = 1;
@@ -1053,6 +1053,7 @@
p->starting_col_offset = 0;
p->flags = flags;
p->feature_version = feature_version;
+ p->known_err_token = NULL;
return p;
}
@@ -1972,12 +1973,7 @@
const char *fstr;
Py_ssize_t fstrlen = -1;
- char *this_str = PyBytes_AsString(t->bytes);
- if (!this_str) {
- goto error;
- }
-
- if (_PyPegen_parsestr(p, this_str, &this_bytesmode, &this_rawmode, &s, &fstr, &fstrlen) != 0) {
+ if (_PyPegen_parsestr(p, &this_bytesmode, &this_rawmode, &s, &fstr, &fstrlen, t) != 0) {
goto error;
}
diff --git a/Parser/pegen/pegen.h b/Parser/pegen/pegen.h
index cbe6f19..ffb18e4 100644
--- a/Parser/pegen/pegen.h
+++ b/Parser/pegen/pegen.h
@@ -71,6 +71,7 @@
int flags;
int feature_version;
growable_comment_array type_ignore_comments;
+ Token *known_err_token;
} Parser;
typedef struct {