Media/WebRTC/libwebrtc Update Process/automation plan

This describes the rough plan to document and automate the process to "fast-forward" through webrtc.org libwebrtc change-sets to bring Firefox's libwebrtc version as close as possible to Chrome. This page will be updated as new information is discovered.

Plan Overview

• repo tasks

- update moz-libwebrtc fork to latest webrtc.org

- update elm to latest moz-central

• verify current third_party/libwebrtc directories
• verify generation/build with extra, unused directories from stock moz-libwebrtc in place
• verify current vendoring scripts cmd-line params

- check moz-central a93c2d1df066 - Bug 1654112 - Vendor libwebrtc for rel86

- check moz-central d1df4970f4f0 - Bug 1654112 - Vendor libwebrtc/third_party for rel86

- check moz-central a93c2d1df066 - Bug 1654112 - Vendor libwebrtc/build for rel86

• verify build instructions for moz-libwebrtc
• remove dead/unused files in third_party/libwebrtc
• identify patch set to "undo" back to vendored moz-libwebrtc
• identify patch set to "undo" back to upstream revision (edd7f9e94d)
• Manually identify how to fast-forward one changeset

- move one changeset forward in webrtc.org history

- verify local build in moz-libwebrtc

- apply moz-libwebrtc-to-upstream patches, verify local build

- vendor moz-libwebrtc

- apply moz-central patches

- full try run

• write automation scripts "Manually identify how to fast-forward one changeset"

Findings

current third_party/libwebrtc directories and status

• Additional vendoring

build (with some changes during vendoring)
third_party

• Mozilla added

README.mozilla - generated during vendoring process
moz.build - generated by generate-gn-build-files.sh
webrtc_gn - generated by generate-gn-build-files.sh
X11 - imported later by Byron in c91f12b557a1 D113830
sdk/BUILD.gn - imported later by Byron in 9314046d89eb D105015
    vendored from incorrect moz-libwebrtc commit (bd4a718667)
sdk/objc - imported later by Byron in 9314046d89eb D105015
    vendored from incorrect moz-libwebrtc commit (bd4a718667)
tools/grit - imported later by Nico in 3cce5e6938f0 D114027

• Untouched from Bug 1665166 - Move media/webrtc/trunk/* to third-party/libwebrtc

README.md   (should have been vendored)
DEPS        (should have been vendored)
google_apis (is this referenced/used by current code?)
tools/clang (is this referenced/used by current code?)            
chromium_deps                   
dummy_file.txt                  
net                             
Makefile.old                    
peerconnection_client.target.mk 
peerconnection.Makefile

verify generation/build with extra, unused directories

• Add missing directories

cp -r ~/git-checkouts/moz-libwebrtc/test ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/pc ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/resources ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/docs ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/tools_webrtc ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/examples ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/p2p ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/rtc_tools ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/data ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/style-guide ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/stats ~/mozilla/moz-central/third_party/libwebrtc/
cp -r ~/git-checkouts/moz-libwebrtc/media/sctp ~/mozilla/moz-central/third_party/libwebrtc/media

• local build file generation produces no build modified build files
• Full build results here using ./mach try fuzzy -q 'build-'
• Full linux test results here using ./mach try fuzzy -q 'linux-'

verify current vendoring scripts cmd-line params

• Vendor libwebrtc (a93c2d1df066)

- The following commands produce a93c2d1df066 with some changes that were checked in on the same commit. We'll need to store a local patch to be applied.

cd dom/media/webrtc/third_party_build
python3 vendor-libwebrtc.py \
        --from-github https://github.com/mozilla/libwebrtc \
        --commit 149d693483e9055f574d9d65b01fe75a186b654b \
        libwebrtc

• Vendor libwebrtc/third_party (d1df4970f4f0)

cd dom/media/webrtc/third_party_build
python3 vendor-libwebrtc.py \
        --from-googlesource \
        --commit 5dc5a4a45df9592baa8e8c5f896006d9193d8e45 \
        third_party

• Vendor libwebrtc/build (587c40771588)

- The following commands produce 587c40771588 with some changes that were checked in on the same commit. We'll need to store a local patch to be applied.

cd dom/media/webrtc/third_party_build
python3 vendor-libwebrtc.py \
        --from-googlesource \
        --commit ac22062b465485d3e1196ae9c506b3617cc16fb5 \
        build

build instructions for moz-libwebrtc

• verify build for webrtc.org
• verify build for moz-libwebrtc

- Use edd7f9e94d because some our patches stacked on top of this upstream revision are specific to building in the moz-central tree.

remove dead/unused files

• Successfully removed:

chromium_deps
dummy_file.txt
net
Makefile.old
peerconnection_client.target.mk
peerconnection.Makefile

- successful try builds

tools/clang

- successful try builds