[snap] chromium launch script forces own start-url when it shouldnt (headless mode)

[miccs]

it is copied from : https://bugs.launchpad.net/ubuntu/+source/snap/+bug/1893020

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the problem is "/snap/chromium/current/bin/chromium.launcher" script,
to be precise these 2 lines below:
exec "$SNAP/usr/lib/chromium-browser/chrome" --no-default-browser-check --no-first-run --password-store=$PASSWORD_STORE $FLASH_OPTIONS $CHROMIUM_FLAGS "$@" "$FIRSTRUN_PAGE"

and

"$SNAP/usr/lib/chromium-browser/chrome" --user-data-dir=$TEMP_PROFILE --no-default-browser-check --no-first-run --password-store=$PASSWORD_STORE $FLASH_OPTIONS $CHROMIUM_FLAGS "$@" "$FIRSTRUN_PAGE"

when --headless options is used "$FIRSTRUN_PAGE" parameter shall never be passed here as user specify his own page here and because of that chromium gives:

"[0826/093125.490825:ERROR:headless_shell.cc(174)] Open multiple tabs is only supported when remote debugging is enabled."

ive patched this script in my snap directory (which is tricky) like this:
copied whole folder "/snap/chromium/1284/bin" to other dir on the disk,
patched script,
then did "sudo mount --bind -o nodev,ro /media/data/chromsc /snap/chromium/1284/bin"

and voila this works

so the solution would be to check if user is passing --headless parameter and if he passes his own site - if so then dont pass "$FIRSTRUN_PAGE" parameter

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additional info regarding solution:

one doesnt need to check if user adds own site because --headless mode can start without website provided, so its enough just to check if user provided --headless parameter.

ive added a patch - which is tested - works perfectly fine.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "chromium.launcher.patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Olivier Tilloy (osomon)]

Fixed with https://git.launchpad.net/~chromium-team/chromium-browser/+git/snap-from-source/commit/?id=8327b5df24a2676d71938c066e48b62b35f25c3b.

[Olivier Tilloy (osomon)]

Thanks miccs, the above commit is largely inspired by your patch.

[Olivier Tilloy (osomon)]

For the record, this bug was making the sabnzbdplus autopkgtests fail (seen on arm64 from 2020-08-26 to 2020-09-04), because they use chromedriver with the "--headless" parameter.