Ryan VanderMeulen
2018-10-12 20:05:34 UTC
When we made the decision to switch to clang-cl for our Windows builds,
MSVC builds and tests were kept running as Tier 2 jobs in CI to ensure that
they continued working in the event of an emergency switch-back caused by
any last-minute clang-cl compatibility issues. Thankfully, no such issues
have arisen and we are on track to ship clang-cl builds with the release of
Firefox 63 on October 23rd.
However, these Tier 2 MSVC builds have been an ongoing source of confusion
for developers since they don't run across all trees all the time and have
been known to break on a fairly regular basis as a result. Also, treating
MSVC as supported but Tier 2 is inconsistent with how we've handled other
compilers, such as GCC, which are still considered Tier 1 in our
infrastructure.
As a result, to avoid confusion and to have a more consistent policy, I've
landed by way of bug 1496059 some changes to how MSVC builds are treated:
* They're now Tier 1 builds, meaning they run across *all* supported
branches on every push and breakage will lead to immediate backout. They
are of course also available for Try pushes as needed.
* Tests no longer run on these builds. This is in line with GCC builds and
was deemed acceptable now that we're past the point of considering
reverting back to MSVC from clang-cl in the builds we ship.
Thanks,
Ryan
MSVC builds and tests were kept running as Tier 2 jobs in CI to ensure that
they continued working in the event of an emergency switch-back caused by
any last-minute clang-cl compatibility issues. Thankfully, no such issues
have arisen and we are on track to ship clang-cl builds with the release of
Firefox 63 on October 23rd.
However, these Tier 2 MSVC builds have been an ongoing source of confusion
for developers since they don't run across all trees all the time and have
been known to break on a fairly regular basis as a result. Also, treating
MSVC as supported but Tier 2 is inconsistent with how we've handled other
compilers, such as GCC, which are still considered Tier 1 in our
infrastructure.
As a result, to avoid confusion and to have a more consistent policy, I've
landed by way of bug 1496059 some changes to how MSVC builds are treated:
* They're now Tier 1 builds, meaning they run across *all* supported
branches on every push and breakage will lead to immediate backout. They
are of course also available for Try pushes as needed.
* Tests no longer run on these builds. This is in line with GCC builds and
was deemed acceptable now that we're past the point of considering
reverting back to MSVC from clang-cl in the builds we ship.
Thanks,
Ryan