Bug#1025268: Should mozjs102 in bookworm use the system icu?

[Simon McVittie]

On Thu, 01 Dec 2022 at 20:38:26 +0200, Adrian Bunk wrote:
> The system icu 72 is no longer older than the icu 71 vendored
> in mozjs102, should mozjs102 in bookworm use the system icu?

Maybe. If someone wants to pursue this, beware that the test suite in
mozjs102 has a tendency to include assertions about the precise behaviour
of functions that are implemented in terms of icu, particularly around
date/time behaviour, such that the tests will fail if icu is older *or
newer* than the vendored version - so the closer we are to bookworm's
icu being frozen, the more likely it is that mozjs102 tests will continue
to pass when the underlying libraries are updated. Are any more icu major
version updates planned before the bookworm freeze?

debian/patches/system-ICU/ contains some patches that were necessary
last time we tried using the system icu (they are intentionally not in
debian/patches/series, we currently use debian/patches/vendored-ICU/
instead). They were most recently used for mozjs91 with system icu
69.1, so they will probably need updates for mozjs102 and icu 72. The
first step would be to do a build with the system icu and none of the
debian/patches/*-ICU/ patches, and see how many tests fail.

I don't know how many of these test failures reflect different behaviour
that will be seen in practice by applications that depend on mozjs102,
most often via gjs. GNOME applications will probably often use GLib
objects like GLib.Date in preference to JavaScript Date objects, so they
are probably insulated from a lot of this.

    smcv