1957123 - Telemetry reports launch success, regardless of outcome

Status: NEW

(Firefox :: Installer, defect, P3)

Description

[Chris DuPuis]

Firefox installer telemetry is showing 100% success rate when attempting to launch the application after installation. Example query: https://sql.telemetry.mozilla.org/queries/106745/source

This is the function where we attempt to launch Firefox after install: https://searchfox.org/mozilla-central/source/browser/installer/windows/nsis/stub.nsh#1145-1167

The first thing this function does is set $FirefoxLaunchCode to 2, which is interpreted as "new_launched" here . $FirefoxLaunchCode is not set after that, so it will be 2 regardless of the result of launching Firefox.

In order to detect failures when attempting to launch Firefox after install, we need to detect failures arising from CreateProcessW here: https://searchfox.org/mozilla-central/source/toolkit/mozapps/installer/windows/nsis/common.nsh#8759 and from WaitForInputIdle here: https://searchfox.org/mozilla-central/source/toolkit/mozapps/installer/windows/nsis/common.nsh#8765, and report a different value for $FirefoxLaunchCode if a failure occurs.