Comment 0 for bug 1848856

At the end of the upgrade from 19.04 to 19.10, the post process of the update-grub reports:

Syntax error at line 185
Syntax errors are detected in generated GRUB config file.
Ensure that there are no errors in /etc/default/grub
and /etc/grub.d/* files or please file a bug report with
/boot/grub/grub.cfg.new file attached.
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
dpkg: error processing package linux-image-5.3.0-18-generic (--configure):
 installed linux-image-5.3.0-18-generic package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 friendly-recovery
 grub-efi-amd64
 grub-efi
 grub-efi-amd64-signed
 shim-signed
 linux-image-5.3.0-18-generic

The system used https://github.com/zfsonlinux/zfs/wiki/Ubuntu-18.04-Root-on-ZFS to add zfs on root to a 19.04 system.

The syntax error in grub.cfg.new is an extra } on line 185. However, comparing the grub.cfg.new to the previously generated grub.cfg under 19.04, there is a significant quantity of configuration missing.

Manually running update-grub generates the same error. /etc/default/grub is the only file changed from default installation to include zswap. This file was not changed prior to upgrade.

The error is reported during the processing of /etc/grub.d/10_linux_zfs which is dated October 11. I attempted the upgrade on 10/18 and have done multiple updates to get the latest kernel and remove old kernels prior to the upgrade. So, I believe the problem is with one of the upgrade modules.