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Add a column offset to JSEvalOptions #1656

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c7a8a33
Add a column offset to JSEvalOptions
claude Aug 6, 2026
3c858b0
Add a test for JSEvalOptions.col_num
claude Aug 7, 2026
b282d2c
Ignore a column offset the source cannot be numbered from
andreasrosdal Aug 7, 2026
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160 changes: 160 additions & 0 deletions api-test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
#undef NDEBUG
#endif
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "quickjs.h"
Expand Down Expand Up @@ -928,6 +929,164 @@ static void new_errors(void)
JS_FreeRuntime(rt);
}

// JSEvalOptions.col_num places the first line of the snippet at a column of
// the enclosing document, the way JSEvalOptions.line_num places it on a line.
// Only the first line is shifted: every subsequent line starts at column 1.
static void eval_options_col_num(void)
{
// returns "line:col" of the first frame of the exception raised by `code`
// evaluated under `options`, or NULL if it did not throw
char buf[64], buf2[64];
JSValue ret, exc, stack;
const char *s, *p;
JSEvalOptions options;

#define EVAL_LOC(code, opts) \
(buf[0] = '\0', \
ret = JS_Eval2(ctx, code, strlen(code), opts), \
assert(JS_IsException(ret)), \
JS_FreeValue(ctx, ret), \
exc = JS_GetException(ctx), \
stack = JS_GetPropertyStr(ctx, exc, "stack"), \
s = JS_ToCString(ctx, stack), \
assert(s), \
p = strstr(s, "eval.js:"), \
assert(p), \
snprintf(buf, sizeof(buf), "%.*s", \
(int)strcspn(p + 8, "\n )"), p + 8), \
JS_FreeCString(ctx, s), \
JS_FreeValue(ctx, stack), \
JS_FreeValue(ctx, exc), \
buf)

@bnoordhuis bnoordhuis Aug 11, 2026

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For all that is holy, please make this a function.


JSRuntime *rt = new_runtime();
JSContext *ctx = JS_NewContext(rt);

options = (JSEvalOptions){
.version = JS_EVAL_OPTIONS_VERSION,
.filename = "eval.js",
};

// the baseline: three spaces then an undefined global, so column 4
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));

// an unset col_num is column 1, and so is an explicit 1
options.col_num = 0;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));
options.col_num = 1;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));

// starting at column 10 moves the first line right by 9
options.col_num = 10;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:13"));
assert(!strcmp(EVAL_LOC("nope", &options), "1:10"));

// a syntax error is placed the same way
assert(!strcmp(EVAL_LOC("let x = ;", &options), "1:18"));

// a large offset is carried through intact
options.col_num = 100000;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:100003"));
options.col_num = 10;

// only the first line is shifted
assert(!strcmp(EVAL_LOC("1;\n nope", &options), "2:4"));
assert(!strcmp(EVAL_LOC("1;\nlet y = ;", &options), "2:9"));

// col_num composes with line_num
options.line_num = 5;
assert(!strcmp(EVAL_LOC(" nope", &options), "5:13"));
assert(!strcmp(EVAL_LOC("1;\n nope", &options), "6:4"));
options.line_num = 0;

// a version 1 caller has no col_num field at all, so a stale value in
// that position must be ignored rather than read
options.version = 1;
options.col_num = 10;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));
options.version = JS_EVAL_OPTIONS_VERSION;

// versions outside the supported range are refused
{
static const int bad[] = { 0, -1, JS_EVAL_OPTIONS_VERSION + 1 };
size_t i;
for (i = 0; i < countof(bad); i++) {
options.version = bad[i];
ret = JS_Eval2(ctx, "1", 1, &options);
assert(JS_IsException(ret));
JS_FreeValue(ctx, ret);
exc = JS_GetException(ctx);
s = JS_ToCString(ctx, exc);
assert(s);
assert(!strcmp(s, "InternalError: bad JSEvalOptions version"));
JS_FreeCString(ctx, s);
JS_FreeValue(ctx, exc);
}
options.version = JS_EVAL_OPTIONS_VERSION;
}

// a successful eval is unaffected by the offset
options.col_num = 10;
ret = JS_Eval2(ctx, "1 + 1", 5, &options);
assert(!JS_IsException(ret));
assert(JS_VALUE_GET_INT(ret) == 2);
JS_FreeValue(ctx, ret);

// a negative offset is not an offset at all
options.col_num = -1;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));
options.col_num = -100000;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));

// neither is one so large that the columns of the source could not be
// numbered from it without overflowing
options.col_num = INT_MAX;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));
options.col_num = INT_MAX - 1;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));
options.col_num = INT_MAX - 7;
assert(!strcmp(EVAL_LOC(" nope", &options), "1:4"));

// the largest offset that does still fit is used as given: " nope" is
// seven bytes, so the last column the parser can reach is col + 7
options.col_num = INT_MAX - 8;
snprintf(buf2, sizeof(buf2), "1:%d", INT_MAX - 5);
assert(!strcmp(EVAL_LOC(" nope", &options), buf2));

// every frame of a multi-frame stack is numbered from the same origin
options.col_num = 10;
options.line_num = 1;
assert(!strcmp(EVAL_LOC("function f() { nope }\n f()", &options), "1:25"));
assert(!strcmp(EVAL_LOC("(function () { nope })()", &options), "1:25"));

// a module is offset the same way a script is
options.eval_flags = JS_EVAL_TYPE_MODULE;
assert(!strcmp(EVAL_LOC(" let x = ;", &options), "1:20"));
assert(!strcmp(EVAL_LOC("1;\nlet x = ;", &options), "2:9"));
options.eval_flags = 0;

// a source whose first line is empty is back to column 1 immediately
assert(!strcmp(EVAL_LOC("\n nope", &options), "2:2"));

// JSON parsing shares the tokenizer but has no column origin of its own
ret = JS_ParseJSON(ctx, "{\"a\":1}", 7, "j.json");
assert(!JS_IsException(ret));
JS_FreeValue(ctx, ret);
ret = JS_ParseJSON(ctx, "{\"a\":}", 6, "j.json");
assert(JS_IsException(ret));
JS_FreeValue(ctx, ret);
exc = JS_GetException(ctx);
s = JS_ToCString(ctx, exc);
assert(s);
JS_FreeCString(ctx, s);
JS_FreeValue(ctx, exc);

#undef EVAL_LOC

JS_FreeContext(ctx);
JS_FreeRuntime(rt);
}

static void backtrace_oom_callsite_array(void)
{
static const char setup_code[] =
Expand Down Expand Up @@ -1840,6 +1999,7 @@ int main(void)
promise_hook();
dump_memory_usage();
new_errors();
eval_options_col_num();
backtrace_oom_current_exception();
backtrace_oom_callsite_array();
proxy_own_keys_huge_length();
Expand Down
51 changes: 35 additions & 16 deletions quickjs.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -615,7 +615,8 @@ struct JSContext {
/* if NULL, eval is not supported */
JSValue (*eval_internal)(JSContext *ctx, JSValueConst this_obj,
const char *input, size_t input_len,
const char *filename, int line, int flags, int scope_idx);
const char *filename, int line, int col, int flags,
int scope_idx);
void *user_opaque;
};

Expand Down Expand Up @@ -1469,7 +1470,8 @@ static void js_async_function_resolve_mark(JSRuntime *rt, JSValueConst val,
JS_MarkFunc *mark_func);
static JSValue JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
const char *input, size_t input_len,
const char *filename, int line, int flags, int scope_idx);
const char *filename, int line, int col,
int flags, int scope_idx);
static void js_free_module_def(JSContext *ctx, JSModuleDef *m);
static int js_module_attributes_equal(JSContext *ctx, JSValueConst attr1,
JSValueConst attr2);
Expand Down Expand Up @@ -38088,21 +38090,31 @@ static __exception int js_parse_program(JSParseState *s)

static void js_parse_init(JSContext *ctx, JSParseState *s,
const char *input, size_t input_len,
const char *filename, int line)
const char *filename, int line, int col)
{
int col_off;

memset(s, 0, sizeof(*s));
s->ctx = ctx;
s->filename = filename;
s->line_num = line;
/* number the first line from `col`, but only while every column of the
source still fits an int; anything else is numbered from 1 */
Comment on lines +38101 to +38102

@bnoordhuis bnoordhuis Aug 11, 2026

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Please drop the "add 1 to i" comment.

s->col_num = 1;
if (col > 0 && input_len < (size_t)(INT32_MAX - col))
s->col_num = col;
Comment on lines +38104 to +38105

@bnoordhuis bnoordhuis Aug 11, 2026

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s->col_num = max_int(1, col);

I don't like how the current code conflates the offset (human visible) with the position in the buffer (machine visible), please do something about that.

(In a previous age I would've made concrete suggestions but since it's going into a slop bot that feels like wasted effort.)

s->buf_start = s->buf_ptr = (const uint8_t *)input;
s->buf_end = s->buf_ptr + input_len;
s->line_start = s->buf_ptr;
/* the first line starts at column `col` of the enclosing document, so
back the two column origins up by that much; both are reset at the
first line terminator, so only the first line is affected */
col_off = s->col_num - 1;
s->line_start = s->buf_ptr - col_off;
s->mark = s->buf_ptr + min_int(1, input_len);
s->eol = s->buf_ptr;
s->eol = s->buf_ptr - col_off;
s->token.val = ' ';
s->token.line_num = 1;
s->token.col_num = 1;
s->token.line_num = line;
s->token.col_num = s->col_num;
}

static JSValue JS_EvalFunctionInternal(JSContext *ctx, JSValue fun_obj,
Expand Down Expand Up @@ -38148,7 +38160,8 @@ JSValue JS_EvalFunction(JSContext *ctx, JSValue fun_obj)
/* `export_name` and `input` may be pure ASCII or UTF-8 encoded */
static JSValue __JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
const char *input, size_t input_len,
const char *filename, int line, int flags, int scope_idx)
const char *filename, int line, int col,
int flags, int scope_idx)
{
JSParseState s1, *s = &s1;
int err, eval_type;
Expand All @@ -38160,7 +38173,7 @@ static JSValue __JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
JSModuleDef *m;
bool is_strict_mode;

js_parse_init(ctx, s, input, input_len, filename, line);
js_parse_init(ctx, s, input, input_len, filename, line, col);
skip_shebang(&s->buf_ptr, s->buf_end);

eval_type = flags & JS_EVAL_TYPE_MASK;
Expand Down Expand Up @@ -38265,7 +38278,8 @@ static JSValue __JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
/* the indirection is needed to make 'eval' optional */
static JSValue JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
const char *input, size_t input_len,
const char *filename, int line, int flags, int scope_idx)
const char *filename, int line, int col,
int flags, int scope_idx)
{
JSRuntime *rt = ctx->rt;

Expand All @@ -38277,7 +38291,7 @@ static JSValue JS_EvalInternal(JSContext *ctx, JSValueConst this_obj,
ctx->error_back_trace = JS_UNDEFINED;
}
return ctx->eval_internal(ctx, this_obj, input, input_len, filename, line,
flags, scope_idx);
col, flags, scope_idx);
}

static JSValue JS_EvalObject(JSContext *ctx, JSValueConst this_obj,
Expand All @@ -38292,7 +38306,8 @@ static JSValue JS_EvalObject(JSContext *ctx, JSValueConst this_obj,
str = JS_ToCStringLen(ctx, &len, val);
if (!str)
return JS_EXCEPTION;
ret = JS_EvalInternal(ctx, this_obj, str, len, "<input>", 1, flags, scope_idx);
ret = JS_EvalInternal(ctx, this_obj, str, len, "<input>", 1, 1, flags,
scope_idx);
JS_FreeCString(ctx, str);
return ret;

Expand All @@ -38317,22 +38332,25 @@ JSValue JS_EvalThis2(JSContext *ctx, JSValueConst this_obj,
{
const char *filename = "<unnamed>";
int line = 1;
int col = 1;
int eval_flags = 0;
if (options) {
if (options->version != JS_EVAL_OPTIONS_VERSION)
if (options->version < 1 || options->version > JS_EVAL_OPTIONS_VERSION)
return JS_ThrowInternalError(ctx, "bad JSEvalOptions version");
if (options->filename)
filename = options->filename;
if (options->line_num != 0)
line = options->line_num;
if (options->version >= 2 && options->col_num != 0)
col = options->col_num;
eval_flags = options->eval_flags;
}
JSValue ret;

assert((eval_flags & JS_EVAL_TYPE_MASK) == JS_EVAL_TYPE_GLOBAL ||
(eval_flags & JS_EVAL_TYPE_MASK) == JS_EVAL_TYPE_MODULE);
ret = JS_EvalInternal(ctx, this_obj, input, input_len, filename, line,
eval_flags, -1);
col, eval_flags, -1);
return ret;
}

Expand Down Expand Up @@ -51178,7 +51196,7 @@ static JSValue JS_ParseJSON_internal(JSContext *ctx, const char *buf, size_t buf
JSParseState s1, *s = &s1;
JSValue val = JS_UNDEFINED;

js_parse_init(ctx, s, buf, buf_len, filename, 1);
js_parse_init(ctx, s, buf, buf_len, filename, 1, 1);
if (json_next_token(s))
goto fail;
val = json_parse_value(s, pr);
Expand Down Expand Up @@ -64776,7 +64794,8 @@ bool JS_DetectModule(const char *input, size_t input_len)
return false;
}
JS_AddIntrinsicRegExpCompiler(ctx); // otherwise regexp literals don't parse
val = __JS_EvalInternal(ctx, JS_UNDEFINED, input, input_len, "<unnamed>", 1,
val = __JS_EvalInternal(ctx, JS_UNDEFINED, input, input_len, "<unnamed>",
1, 1,
JS_EVAL_TYPE_MODULE|JS_EVAL_FLAG_COMPILE_ONLY, -1);
if (JS_IsException(val)) {
const char *msg = JS_ToCString(ctx, rt->current_exception);
Expand Down
4 changes: 3 additions & 1 deletion quickjs.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -694,13 +694,15 @@ typedef struct JSClassDef {
JSClassExoticMethods *exotic;
} JSClassDef;

#define JS_EVAL_OPTIONS_VERSION 1
#define JS_EVAL_OPTIONS_VERSION 2

typedef struct JSEvalOptions {
int version;
int eval_flags;
const char *filename;
int line_num;
// added in version 2
int col_num;
// can add new fields in ABI-compatible manner by incrementing JS_EVAL_OPTIONS_VERSION
} JSEvalOptions;

Expand Down
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