Waybar: Crash on launch on Arch Linux (libspdlog.so)

[atomheartother]

I have not upgraded spdlog or waybar lately but after my latest upgrade waybar appears to crash, with this error:

waybar: symbol lookup error: /usr/lib/libspdlog.so.1: undefined symbol: _ZN3fmt2v76detail10vformat_toIcEENS0_20basic_format_contextISt20back_insert_iteratorINS1_6bufferIT_EEES6_E8iteratorERS7_NS0_17basic_string_viewIS6_EENS0_17basic_format_argsINS3_IS4_INS5_INS0_13type_identityIS6_E4typeEEEESH_EEEE

Here are the packages I've upgraded since last time waybar worked, i'll be investigating them:

[2020-10-27T18:23:21+0100] [ALPM] upgraded fmt (7.0.3-1 -> 7.1.0-1)
[2020-10-27T18:23:21+0100] [ALPM] upgraded gstreamer (1.18.0-1 -> 1.18.1-1)
[2020-10-27T18:23:21+0100] [ALPM] upgraded gst-plugins-base-libs (1.18.0-1 -> 1.18.1-1)
[2020-10-27T18:23:21+0100] [ALPM] upgraded libass (0.14.0-2 -> 0.15.0-2)
[2020-10-27T18:23:21+0100] [ALPM] upgraded libbluray (1.2.0-3 -> 1.2.1-1)
[2020-10-27T18:23:21+0100] [ALPM] upgraded libnewt (0.52.21-3 -> 0.52.21-4)
[2020-10-27T18:23:21+0100] [ALPM] upgraded libva (2.9.0-1 -> 2.9.1-1)
[2020-10-27T18:23:22+0100] [ALPM] upgraded npm (6.14.8-1 -> 6.14.8-2)

Waybar 0.9.4

[atomheartother]

Well, that was fast, it's fmt, downgrading to fmt:7.0.3-1 fixed it.

Is this a fmt bug, a spdlog bug or a waybar one?

Edit: For the lazy, here's the commmand with pacman to downgrade:

sudo pacman -U /var/cache/pacman/pkg/fmt-7.0.3-1-x86_64.pkg.tar.zst

[GbGp]

fmt apparently: https://github.com/fmtlib/fmt/issues/1961

[atomheartother]

This isn't a waybar bug so I'm closing this, discussion of the bug should be in that fmt thread :)

Edit: Updating your packages should now fix it.