[Google Pixel 4a 5G Questions & Answers] :
Greetings.

So ever since (Late April?) the LineageOS 18.1 official builds for the Pixel 4a5g (bramble) stopped and are now on 19.1, I was curious to endevour into the world of building. I wasn't ready to upgrade to Android 12 yet and so I wanted to see if I could build an equivlent up-to-date unoffical "nighly" build for my device. BIG MISTAKE, haha. I had to go through many trial and error build runs having to deal with everything from out of memory (ram), out of hard drive space (200gb+!!), out of java heap space, build failed (after 12-18 hours!). Oh yea, and I'm doing this all on an AMD A-10 6800k (circa 2013?) with 16GB of ram but on a virtual machine w/ around 12GB of RAM and utilizing all 4 cores writing inside a 500gb VDI HDD vm container file with a 30gb /swap partition on Debian 11. Good times.

So anyhow, since I'm having to wait for these builds to finish, I can now qualfiy for Social Security. To those people with super-duper 8/10/16/32+ core cpu's with 32-64GB ram able to build complete roms within 40min to an hour (or 2)--I hate you. ;)

So after all the trial and errors and LEARNING. I have finally been able to complete a build! At first I was missing vender blobs but was able to pull them with TheMuppets repo.

I followed these guides (substituting 18.1 for 19.1):

https://wiki.lineageos.org/devices/bramble/build (following just this would fail the build after a few eons with various errors)

(these 2 youtube vids helped me with creating roomservice.xml and pulling vendor blobs vs extraction via rom/firmware.zip or device).

Some of the errors during the builds (not necessessarly both as just one of these errors would stop the whole process. The errors are combined here for reference as these were obtained on a trial and error basis (Try this. fail. Try this...get little further fail, try this build suceeded with warnings, etc etc)

java.lang.OutOfMemoryError: Java heap space
ERROR:payload_generation_config.cc(200)] Sum of sizes in google_dynamic_partitions_partition_list is 4879237120, which is greater than google_dynamic_partitions_size (4873781248)
FATAL:generate_delta_main.cc(619)] Check failed: payload_config.target.ValidateDynamicPartitionMetadata().

It took around 18 hours for it to attempt to build and end with those errors, which were resolved by a couple 'export' commands I entered before re-running the build(s):

export _JAVA_OPTIONS=-Xmx2096m

or

export _JAVA_OPTIONS="-Xmx4g"

or was it

export JACK_SERVER_VM_ARGUMENTS="-Dfile.encoding=UTF-8 -XX:+TieredCompilation -Xmx4096m"

(my mind is a little mush so I don't rememer which one(s))

and

export WITH_GMS=true

re-ran brunch bramble and it compiled and only took about 40 minutes this time. Probally because I had ccache enabled per the build instructions.

YAY it built. But I am concerned about a couple warnings I recieved during the build process:

Should I be worried about these warnings? Can anyone advise?

depmod: WARNING: could not open modules.order at /home/user/android/lineage/out/target/product/bramble/obj/PACKAGING/depmod_vendor_intermediates/lib/modules/0.0: No such file or directory
depmod: WARNING: could not open modules.builtin at /home/user/android/lineage/out/target/product/bramble/obj/PACKAGING/depmod_vendor_intermediates/lib/modules/0.0: No such file or directory
depmod: WARNING: could not open modules.order at /home/user/android/lineage/out/target/product/bramble/obj/PACKAGING/depmod_vendor_ramdisk_intermediates/lib/modules/0.0: No such file or directory
depmod: WARNING: could not open modules.builtin at /home/user/android/lineage/out/target/product/bramble/obj/PACKAGING/depmod_vendor_ramdisk_intermediates/lib/modules/0.0: No such file or directory

This is my first ever attempt at building LineageOS from source, so I'm a little proud of myself for making it this far. But any help on those warnings, if I even need to worry about it, would be appreciated. I have NOT flashed this new unoffical build yet.

Thank you!

* Logs can be provided upon request. I think there are many to choose from it seems in the /out folder.