[New-bugs-announce] [issue35203] Windows Installer Ignores Launcher Installer Options Where The Python Launcher Is Already Present

[Dexter]

New submission from Dexter <dexter.lowe at gresearch.co.uk>:

When installing Python 3.7 from the Windows Installer in a restricted environment the installer appears to ignore the InstallLauncherAllUsers=0 and Include_launcher=0 flags if the launcher is already present from a previous install.

I am on a machine where the system python is centrally controlled and cannot be modified by me. In previous versions I have installed personal copies using the InstallLauncherAllUsers=0 InstallAllUsers=0 as exemplified in the docs or just unticking in the UI. However in 3.7 the tick-box for the launcher is ticked but greyed out in the UI. I am unable to de-select it and, as I do not have permission to modify the system wide launcher, I cannot install Python 3.7.

My suspicion is that the box is greyed out if someone has installed the site wide version to ensure the site wide version is in-line with the installer but:

a) What if this is an older version and I do not want it replaced.
b) What if a user like me can't upgrade that script and is happy to have a version that will not be understood by the launcher for other purposes.

Assuming there is no current workaround. I propose that either we remove this restriction or at least allow an override. e.g. ForceExistingLauncherUpgrade=1 by default to preserve current behaviour and if 0 then allow the other launcher exclusions to apply.

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components: Windows
messages: 329550
nosy: gr-dexterl, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: Windows Installer Ignores Launcher Installer Options Where The Python Launcher Is Already Present
type: behavior
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue35203>
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