How to rename installation folder for new versions in Inno Setup?

Question

I use a side-by-side installation of my software where each new version is installed into a separate folder, for example MySoftware2, MySoftware3 etc. This was not a good idea and I would like to move to a single folder installation where all installations and updates would be into MySoftware folder (without version numbers).

For all fresh installs the folder would be

DefaultDirName={pf}\MySoftware

But what about the auto updates from the previous versions of the software (for example from v3 to v4)? I guess those should be installed into existing folder (MySoftware3) and then renamed? How can Inno know the existing folder and could Inno rename the installation directory after the installation?

Any idea how to do this properly? Thanks.

Answer 1

To rename a installation folder, you can use RenameFile function from CurStepChanged(ssPostInstall). That's the easy part.

But you also need to update the uninstall registry information. That's much more work.

Something like this will do.

#define AppId "My Program"

[Setup]
AppId={#AppId}

[Code]

const
  OldDirName = 'MySoftware3';
  NewDirName = 'MySoftware';
  InnoSetupReg =
    'Software\Microsoft\Windows\CurrentVersion\Uninstall\{#AppId}_is1';

var
  Path, NewPath: string;
  RootKey: Integer;

function CheckRegistry(
  ValueName: string; var P: Integer; var Value: string): Boolean;
begin
  if not RegQueryStringValue(RootKey, InnoSetupReg, ValueName, Value) then
  begin
    Log(Format('Cannot find uninstall registry value "%s" in key %s', [
      ValueName, InnoSetupReg]));
    Result := False;
  end
    else
  begin
    P := Pos(Lowercase(Path), Lowercase(Value));
    Result := (P > 0);
    if not Result then
    begin
      Log(Format(
        'Uninstall registry value "%s" in key %s "%s" ' +
          'does not contain the installation path "%s"', [
        ValueName, InnoSetupReg, Value, Path]));
    end;
  end
end;

procedure UpdateRegistry(ValueName: string);
var
  Value, NewValue: string;
  P: Integer;
begin
  if CheckRegistry(ValueName, P, Value) then
  begin
    NewValue :=
      Copy(Value, 1, P - 1) +
      NewPath +
      Copy(Value, P + Length(Path), Length(Value) - P - Length(Path) + 1);
    if not RegWriteStringValue(RootKey, InnoSetupReg, ValueName, NewValue) then
    begin
      Log(Format('Cannot write uninstall registry value "%s" in key %s', [
        ValueName, InnoSetupReg]));
    end
      else
    begin
      Log(Format('Updated uninstall registry value "%s" from "%s" to "%s"', [
        ValueName, Value, NewValue]));
    end;
  end;
end;

procedure CurStepChanged(CurStep: TSetupStep);
var
  Value: string;
  P: Integer;
begin
  Log(Format('CurStepChanged %d', [CurStep]));
  if CurStep = ssPostInstall then
  begin
    Path := ExpandConstant('{app}');
    if CompareText(ExtractFileName(Path), OldDirName) = 0 then
    begin
      Log(Format(
        'Program was installed to old folder name "%s", trying to rename...', [
          Path]));
      NewPath := ExtractFilePath(Path) + NewDirName;

      if IsAdminInstallMode then RootKey := HKLM
        else RootKey := HKCU;

      if CheckRegistry('UninstallString', P, Value) then
      begin
        if not RenameFile(Path, NewPath) then
        begin
          Log('Failed to rename');
        end
          else
        begin
          Log('Renamed, updating uninstall registry information...');
          UpdateRegistry('UninstallString');
          UpdateRegistry('QuietUninstallString');
          UpdateRegistry('DisplayIcon');
          UpdateRegistry('Inno Setup: App Path');
          UpdateRegistry('InstallLocation');
          Log('Installation path rename done');
        end;
      end;
    end;
  end;
end;

Though note that it relies old name not to be part of the new name, like you have it now (MySoftware3 => MySoftware). Otherwise it would keep renaming with every update.