Closed
Description
Describe the bug
As part of the Melange playground, we create a version of ocamlformat that we can run on the browser.
When updating to the most recent version of jsoo, we noticed an error when creating this JS version of ocamlformat: https://github.com/melange-re/melange-re.github.io/actions/runs/7139925249/job/19444213740#step:15:44
The error comes from esbuild, I paste below some details.
Part of the error (click to open)
There is no containing label named "b"
17821| 11:var
17822| h=a[1],c=h[1];if(typeof
17823| c!=="number"&&14===c[0]){if(c[2])break b;if(h[4])break b;var
| ^
17824| i=a[2],f=i[1];if(typeof
17825| f!=="number"&&9===f[0]){if(i[4])break b;return [0,[14,c[1],[0,f[1]]],b[2],b[3],b[4]]}break b}break b;case
There is no containing label named "b"
17821| 11:var
17822| h=a[1],c=h[1];if(typeof
17823| c!=="number"&&14===c[0]){if(c[2])break b;if(h[4])break b;var
| ^
17824| i=a[2],f=i[1];if(typeof
17825| f!=="number"&&9===f[0]){if(i[4])break b;return [0,[14,c[1],[0,f[1]]],b[2],b[3],b[4]]}break b}break b;case
There is no containing label named "b"
17823| c!=="number"&&14===c[0]){if(c[2])break b;if(h[4])break b;var
17824| i=a[2],f=i[1];if(typeof
17825| f!=="number"&&9===f[0]){if(i[4])break b;return [0,[14,c[1],[0,f[1]]],b[2],b[3],b[4]]}break b}break b;case
| ^
17826| 18:var
17827| d=a[1];if(!d)break b;var
Debugging notes
- The error only happens with using
profile=releasebut it does not occur withprofile=dev. - It only happens when trying to process large programs, like ocamlformat or the melange compiler. I have not been able to reproduce or isolate using small programs.
- After dissecting back in time through the past commits of jsoo, we found the regression starts happening after commit 29c693b (Compiler: refactor control flow compilation #1496), with 3ddba6b being the last commit that works fine.
- One thing I noticed in the generated code is that there are two nested
blabels, see the extracted section of the generated code below:
Section of generated minified JS that causes the failure (click to open)
function q(g, b) {
var a = b[1];
b: if (typeof a !== "number")
switch (a[0]) {
case 7:
var q = a[2],
r = a[1],
t = bS(r, function (a) {
var c = a[3],
d = a[2],
b = a[1];
b: if (c) {
var h = c[1],
e = h[1];
if (typeof e !== "number")
switch (e[0]) {
case 0:
if (h[4]) break b;
if (tp(b[1], [0, e[1][1]])) return [0, b, d, 0];
break b;
case 11:
if (d) break b;
var i = c[1],
k = i[1],
l = k[1],
f = l[1];
if (typeof f !== "number" && 0 === f[0]) {
if (l[4]) break b;
if (i[4]) break b;
var m = k[2],
n = f[1][1];
if (j && tp(b[1], [0, n]))
return [0, b, [0, m], 0];
break b;
}
break b;
}
}
return [0, b, d, o(eR, c, p(g[33], g))];
});
return [0, [7, t, q], b[2], b[3], b[4]];
case 11:
var h = a[1],
c = h[1];
if (typeof c !== "number" && 14 === c[0]) {
if (c[2]) break b; /* <--- error triggered here */
if (h[4]) break b;
var i = a[2],
f = i[1];
if (typeof f !== "number" && 9 === f[0]) {
if (i[4]) break b;
return [0, [14, c[1], [0, f[1]]], b[2], b[3], b[4]];
}
break b;
}
break b;
case 18:
var d = a[1];
if (!d) break b;
var k = d[2];
if (!k) break b;
if (!k[2]) break b;
var l = dm(d),
e = l[1];
d: {
e: if (typeof e !== "number" && 5 === e[0]) {
var n = e[1][1];
if (0 !== n[0]) break e;
if (s(n[1], d1)) break e;
if (e[2]) break e;
if (l[4]) break e;
var m = 1;
break d;
}
var m = 0;
}
if (!m) break b;
var u = b6(o8(b6(d)));
return [0, [9, u], b[2], b[3], b[4]];
}
return Cs(g, b);
}Expected behavior
Js_of_ocaml should generate code that is usable by other JavaScript tooling.
Versions
See section "Debugging notes" above about commits.