Dangerous example of MUI_STARTMENU_GETFOLDER macro

Logged In: YES
user_id=604457
Originator: NO

It doesn't really look dangerous to me.

First of all the default folder will be returned if the registry value is empty. The default for this default folder is the installer name, which again can never be empty because NSIS also has a default for that. So $R0 should never be empty.

And even if $R0 would be empty, the uninstaller would just attempt to remove "Your Shortcut.lnk" from the main Start Menu programs folder instead of the subfolder for the application. Delete also won't remove folders nor their content.

Only when using commands like RMDir /r you should really be careful with possible empty variables. By the way, using RMDir /r in an uninstaller is usually not a good idea.

Please clarify if I misunderstood your report.

Logged In: YES
user_id=1022691
Originator: YES

Well, the value returned was empty for NSIS 2.34 at my machine, I message-boxed it. I used RMDir /r on that folder. RMDir /r on a start menu folder should be fine since user don't put files in there.

I opened this bug because I actually deleted a whole start menu this way by mistake.

Logged In: YES
user_id=1022691
Originator: YES

or to say it this way: if no shortcuts were created
then executing

!insertmacro MUI_STARTMENU_GETFOLDER page_id $R0
Delete "$SMPROGRAMS\$R0\Your Shortcut.lnk"

can only do damage.

Logged In: YES
user_id=604457
Originator: NO

Can you provide a small script to reproduce this issue (the returned variable being empty)? I cannot reproduce it.

Empty start menu folder variable bug demo

Logged In: YES
user_id=1022691
Originator: YES

Here is the requested demo script.
Be sure to check "do not create shortcuts".

NSIS version: 2.34
System: Windows Server 2003 Enterprise SP2
File Added: empty_start_menu_folder.nsi

Logged In: YES
user_id=1022691
Originator: YES

Addendum: I just noticed my example script was missing the line

!define APP_START_MENU_PAGE_ID "StartMenuPage"

so the page id is probably empty. I re-tried with that line but still the same.
Are these macros expected to work with an empty page id?

Logged In: YES
user_id=604457
Originator: NO

You're right, this is a bug in the Modern UI version 2.0. It works fine with Modern UI 1.x.

The fix will be included in NSIS version 2.35. To solve it right now for your 2.34 version, replace Contrib\Modern UI
2\Pages\StartMenu.nsh will the attached file.

By the way, you don't need to check whether the variable that contains the Start Menu folder starts with ">". The MUI_STARTMENU_WRITE_BEGIN / MUI_STARTMENU_WRITE_END macros will verify that.
File Added: StartMenu.nsh

Logged In: YES
user_id=1022691
Originator: YES

I had a look at the new .nsh file. I am wondering if the variable is corrected to the default value then we end up deleting files that are not there. Should we instead delete no files at all? Is there a way for the uninstaller to find out whether start menu entries have been created or not? If not maybe we need another macro?

Logged In: YES
user_id=604457
Originator: NO

The default Start Menu folder is the most likely location of the shortcuts, most users do not change it. If the registry value is somehow missing, it's not a bad guess to try to delete the shortcuts from the default location.