Question

I am trying to dynamically set the SetOverwrite state for choosing between unconditionally replace some files or replace them only if my setup is providing some newer versions.

I have tried with logiclib

${if} $isReinstall = 1
    SetOverwrite on
    ${debug} "SetOverwrite on (overwrite)"
${else}
    SetOverwrite ifnewer
    ${debug} "SetOverwrite ifnewer"
${endif}
File "foo"

And with classic IntCmp

IntCmp $isReinstall 1 0 +3 +3
SetOverwrite on
goto +2
SetOverwrite ifnewer
File "foo"

But nothing seem to work: if my file foo is already present on disk, it is always skipped. My $isReinstall being 1 or not.

It seems that the last SetOverwrite statement in the stream of instructions (regardless of the logiclib macros) overloads the previous one.

If I add another SetOverwrite on just before the File directive, the file is correctly replaced.

Is my analysis correct? How could I decide at runtime if a file can or cannot be replaced?

Answer 1

Try using this code instead:

${If} $isReinstall = 1
  SetOverwrite on
  File "foo"
${Else}
  SetOverwrite ifnewer
  File "foo"
${EndIf}

The important point to note is that the File command appears within the If block and this needs to be done because the SetOverwrite command affects every line below it. See this piece of the NSIS documentation for a full explanation.