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bpo-45635: standardize error handling in traceback.c #29905

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Merged
merged 6 commits into from
Dec 7, 2021
Merged

bpo-45635: standardize error handling in traceback.c #29905

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b6a0e1c
bpo-45635: standardize error handling in traceback.c
iritkatriel Dec 3, 2021
afca4c7
Erlend's style suggestions
iritkatriel Dec 3, 2021
c18f6ea
don't use gotos if there is no cleanup to do
iritkatriel Dec 5, 2021
0e25738
== -1 --> < 0
iritkatriel Dec 7, 2021
1534468
remove unnecessary assert
iritkatriel Dec 7, 2021
a05ac63
Erlend's latest comments
iritkatriel Dec 7, 2021
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170 changes: 104 additions & 66 deletions Python/traceback.c
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Original file line number Diff line number Diff line change
Expand Up @@ -385,16 +385,14 @@ _Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *
int
_Py_WriteIndent(int indent, PyObject *f)
{
int err = 0;
char buf[11] = " ";
assert(strlen(buf) == 10);
while (indent > 0) {
if (indent < 10) {
buf[indent] = '\0';
}
err = PyFile_WriteString(buf, f);
if (err != 0) {
return err;
if (PyFile_WriteString(buf, f) < 0) {
return -1;
}
indent -= 10;
}
Expand All @@ -407,19 +405,22 @@ _Py_WriteIndent(int indent, PyObject *f)
int
_Py_WriteIndentedMargin(int indent, const char *margin, PyObject *f)
{
int err = _Py_WriteIndent(indent, f);
if (err == 0 && margin) {
err = PyFile_WriteString(margin, f);
if (_Py_WriteIndent(indent, f) < 0) {
return -1;
}
return err;
if (margin) {
if (PyFile_WriteString(margin, f) < 0) {
return -1;
}
}
return 0;
}

static int
display_source_line_with_margin(PyObject *f, PyObject *filename, int lineno, int indent,
int margin_indent, const char *margin,
int *truncation, PyObject **line)
{
int err = 0;
int fd;
int i;
char *found_encoding;
Expand Down Expand Up @@ -502,19 +503,20 @@ display_source_line_with_margin(PyObject *f, PyObject *filename, int lineno, int
lineobj = PyFile_GetLine(fob, -1);
if (!lineobj) {
PyErr_Clear();
err = -1;
break;
}
}
res = _PyObject_CallMethodIdNoArgs(fob, &PyId_close);
if (res)
if (res) {
Py_DECREF(res);
else
}
else {
PyErr_Clear();
}
Py_DECREF(fob);
if (!lineobj || !PyUnicode_Check(lineobj)) {
Py_XDECREF(lineobj);
return err;
return -1;
}

if (line) {
Expand Down Expand Up @@ -545,23 +547,29 @@ display_source_line_with_margin(PyObject *f, PyObject *filename, int lineno, int
*truncation = i - indent;
}

if (err == 0) {
err = _Py_WriteIndentedMargin(margin_indent, margin, f);
if (_Py_WriteIndentedMargin(margin_indent, margin, f) < 0) {
goto error;
}

/* Write some spaces before the line */
if (err == 0) {
err = _Py_WriteIndent(indent, f);
if (_Py_WriteIndent(indent, f) < 0) {
goto error;
}

/* finally display the line */
if (err == 0) {
err = PyFile_WriteObject(lineobj, f, Py_PRINT_RAW);
if (PyFile_WriteObject(lineobj, f, Py_PRINT_RAW) < 0) {
goto error;
}
Py_DECREF(lineobj);
if (err == 0) {
err = PyFile_WriteString("\n", f);

if (PyFile_WriteString("\n", f) < 0) {
goto error;
}
return err;

Py_DECREF(lineobj);
return 0;
error:
Py_DECREF(lineobj);
return -1;
}

int
Expand Down Expand Up @@ -723,41 +731,51 @@ static inline int
print_error_location_carets(PyObject *f, int offset, Py_ssize_t start_offset, Py_ssize_t end_offset,
Py_ssize_t right_start_offset, Py_ssize_t left_end_offset,
const char *primary, const char *secondary) {
int err = 0;
int special_chars = (left_end_offset != -1 || right_start_offset != -1);
const char *str;
while (++offset <= end_offset) {
if (offset <= start_offset || offset > end_offset) {
err = PyFile_WriteString(" ", f);
str = " ";
} else if (special_chars && left_end_offset < offset && offset <= right_start_offset) {
err = PyFile_WriteString(secondary, f);
str = secondary;
} else {
err = PyFile_WriteString(primary, f);
str = primary;
}
if (PyFile_WriteString(str, f) < 0) {
return -1;
}
}
err = PyFile_WriteString("\n", f);
return err;
if (PyFile_WriteString("\n", f) < 0) {
return -1;
}
return 0;
}

static int
tb_displayline(PyTracebackObject* tb, PyObject *f, PyObject *filename, int lineno,
PyFrameObject *frame, PyObject *name, int margin_indent, const char *margin)
{
int err;
PyObject *line;
if (filename == NULL || name == NULL) {
return -1;
}

if (filename == NULL || name == NULL)
if (_Py_WriteIndentedMargin(margin_indent, margin, f) < 0) {
return -1;
line = PyUnicode_FromFormat(" File \"%U\", line %d, in %U\n",
filename, lineno, name);
if (line == NULL)
}

PyObject *line = PyUnicode_FromFormat(" File \"%U\", line %d, in %U\n",
filename, lineno, name);
if (line == NULL) {
return -1;
err = _Py_WriteIndentedMargin(margin_indent, margin, f);
if (err == 0) {
err = PyFile_WriteObject(line, f, Py_PRINT_RAW);
}

int res = PyFile_WriteObject(line, f, Py_PRINT_RAW);
Py_DECREF(line);
if (err != 0)
return err;
if (res < 0) {
return -1;
}

int err = 0;

int truncation = _TRACEBACK_SOURCE_LINE_INDENT;
PyObject* source_line = NULL;
Expand Down Expand Up @@ -849,11 +867,16 @@ tb_displayline(PyTracebackObject* tb, PyObject *f, PyObject *filename, int linen
end_offset = i + 1;
}

err = _Py_WriteIndentedMargin(margin_indent, margin, f);
if (err == 0) {
err = print_error_location_carets(f, truncation, start_offset, end_offset,
right_start_offset, left_end_offset,
primary_error_char, secondary_error_char);
if (_Py_WriteIndentedMargin(margin_indent, margin, f) < 0) {
err = -1;
goto done;
}

if (print_error_location_carets(f, truncation, start_offset, end_offset,
right_start_offset, left_end_offset,
primary_error_char, secondary_error_char) < 0) {
err = -1;
goto done;
}

done:
Expand Down Expand Up @@ -884,7 +907,7 @@ static int
tb_printinternal(PyTracebackObject *tb, PyObject *f, long limit,
int indent, const char *margin)
{
int err = 0;
PyCodeObject *code = NULL;
Py_ssize_t depth = 0;
PyObject *last_file = NULL;
int last_line = -1;
Expand All @@ -899,35 +922,45 @@ tb_printinternal(PyTracebackObject *tb, PyObject *f, long limit,
depth--;
tb = tb->tb_next;
}
while (tb != NULL && err == 0) {
PyCodeObject *code = PyFrame_GetCode(tb->tb_frame);
while (tb != NULL) {
code = PyFrame_GetCode(tb->tb_frame);
if (last_file == NULL ||
code->co_filename != last_file ||
last_line == -1 || tb->tb_lineno != last_line ||
last_name == NULL || code->co_name != last_name) {
if (cnt > TB_RECURSIVE_CUTOFF) {
err = tb_print_line_repeated(f, cnt);
if (tb_print_line_repeated(f, cnt) < 0) {
goto error;
}
}
last_file = code->co_filename;
last_line = tb->tb_lineno;
last_name = code->co_name;
cnt = 0;
}
cnt++;
if (err == 0 && cnt <= TB_RECURSIVE_CUTOFF) {
err = tb_displayline(tb, f, code->co_filename, tb->tb_lineno,
tb->tb_frame, code->co_name, indent, margin);
if (err == 0) {
err = PyErr_CheckSignals();
if (cnt <= TB_RECURSIVE_CUTOFF) {
if (tb_displayline(tb, f, code->co_filename, tb->tb_lineno,
tb->tb_frame, code->co_name, indent, margin) < 0) {
goto error;
}

if (PyErr_CheckSignals() < 0) {
goto error;
}
}
Py_DECREF(code);
Py_CLEAR(code);
tb = tb->tb_next;
}
if (err == 0 && cnt > TB_RECURSIVE_CUTOFF) {
err = tb_print_line_repeated(f, cnt);
if (cnt > TB_RECURSIVE_CUTOFF) {
if (tb_print_line_repeated(f, cnt) < 0) {
goto error;
}
}
return err;
return 0;
error:
Py_XDECREF(code);
return -1;
}

#define PyTraceBack_LIMIT 1000
Expand All @@ -936,12 +969,12 @@ int
_PyTraceBack_Print_Indented(PyObject *v, int indent, const char *margin,
const char *header_margin, const char *header, PyObject *f)
{
int err;
PyObject *limitv;
long limit = PyTraceBack_LIMIT;

if (v == NULL)
if (v == NULL) {
return 0;
}
if (!PyTraceBack_Check(v)) {
PyErr_BadInternalCall();
return -1;
Expand All @@ -957,14 +990,19 @@ _PyTraceBack_Print_Indented(PyObject *v, int indent, const char *margin,
return 0;
}
}
err = _Py_WriteIndentedMargin(indent, header_margin, f);
if (err == 0) {
err = PyFile_WriteString(header, f);
if (_Py_WriteIndentedMargin(indent, header_margin, f) < 0) {
return -1;
}

if (PyFile_WriteString(header, f) < 0) {
return -1;
}
if (err == 0) {
err = tb_printinternal((PyTracebackObject *)v, f, limit, indent, margin);

if (tb_printinternal((PyTracebackObject *)v, f, limit, indent, margin) < 0) {
return -1;
}
return err;

return 0;
}

int
Expand Down