[Issue 23642] New: DMD installer should set up PATH in the same order as it was before reinstall

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23642

          Issue ID: 23642
           Summary: DMD installer should set up PATH in the same order as
                    it was before reinstall
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: installer
          Assignee: nobody at puremagic.com
          Reporter: andrej.mitrovich at gmail.com

It seems that reinstalling DMD on Windows will cause it to first uninstall and
remove DMD from PATH, and then install it and add DMD to PATH as the *last*
entry.

This can cause unexpected problems, for example:

- If there is no user-provided dub settings file (https://dub.pm/settings)
- And if another D compiler is installed and is in PATH, e.g. LDC
- And if the DMD was in PATH before LDC

Then after installing a new version of DMD via the installer the LDC compiler
will be picked up by default by DUB.

Of course one can set up the default with https://dub.pm/settings, but the user
may not be aware of that.

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