Unregister .iss association from both HKCU and HKLM, and remove all the conditional deletion code.

Before the "Open with" menu existed, if an app wanted to add itself to an existing association's context menu without taking over the association completely, it had to modify the ProgID key of whatever app owned the association. To allow for that, we previously were very careful to only delete keys/values under InnoSetupScriptFile that we created.



But there's no longer any need for that. If an app wants an "Open with" item, it should register its own ProgID and add a value under ".iss\OpenWithProgids" linking to it.

Projects/Src/IDE.FileAssocFunc.pas

@@ -27,7 +27,7 @@ begin
     Result := HKEY_CURRENT_USER;
 end;
 
-procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY; const ChangeNotify: Boolean); forward;
+procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY); forward;
 
 function RegisterISSFileAssociation(const AllowInteractive: Boolean; var AllUsers: Boolean): Boolean;
 
@@ -85,108 +85,35 @@ begin
 
   { If we just associated for all users, remove our existing association for the current user if it exists. }
   if AllUsers then
-    UnregisterISSFileAssociationDo(HKEY_CURRENT_USER, False);
+    UnregisterISSFileAssociationDo(HKEY_CURRENT_USER);
 
   SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
 end;
 
-procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY; const ChangeNotify: Boolean);
-
-  function KeyValueEquals(const Rootkey: HKEY; const Subkey: PChar; const Data: String): Boolean;
-  var
-    K: HKEY;
-    S: String;
-  begin
-    Result := False;
-    if RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_QUERY_VALUE, K) = ERROR_SUCCESS then begin
-      if RegQueryStringValue(K, nil, S) and (PathCompare(Data, S) = 0) then
-        Result := True;
-      RegCloseKey(K);
-    end;
-  end;
-
-  function KeyExists(const Rootkey: HKEY; const Subkey: PChar): Boolean;
-  var
-    K: HKEY;
-  begin
-    Result := (RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_QUERY_VALUE,
-      K) = ERROR_SUCCESS);
-    if Result then
-      RegCloseKey(K);
-  end;
-
-  function GetKeyNumSubkeysValues(const Rootkey: HKEY; const Subkey: PChar;
-    var NumSubkeys, NumValues: DWORD): Boolean;
-  var
-    K: HKEY;
-  begin
-    Result := False;
-    if RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_QUERY_VALUE, K) = ERROR_SUCCESS then begin
-      Result := RegQueryInfoKey(K, nil, nil, nil, @NumSubkeys, nil, nil,
-        @NumValues, nil, nil, nil, nil) = ERROR_SUCCESS;
-      RegCloseKey(K);
-    end;
-  end;
-
-  procedure DeleteValue(const Rootkey: HKEY; const Subkey, ValueName: PChar);
-  var
-    K: HKEY;
-  begin
-    if RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_SET_VALUE, K) = ERROR_SUCCESS then begin
-      RegDeleteValue(K, ValueName);
-      RegCloseKey(K);
-    end;
-  end;
-
-var
-  SelfName: String;
-  NumSubkeys, NumValues: DWORD;
+procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY);
 begin
-  if not KeyExists(Rootkey, 'Software\Classes\InnoSetupScriptFile') and
-     not KeyExists(Rootkey, 'Software\Classes\.iss') and
-     not KeyExists(Rootkey, 'Software\Classes\Applications\Compil32.exe') then
-    Exit;
-
-  SelfName := NewParamStr(0);
+  { Remove 'InnoSetupScriptFile' entirely. We own it. }
+  RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey,
+    'Software\Classes\InnoSetupScriptFile');
 
-  { NOTE: We can't just blindly delete the entire .iss & InnoSetupScriptFile
-    keys, otherwise we'd remove the association even if we weren't the one who
-    registered it in the first place. }
-
-  { Clean up 'InnoSetupScriptFile' }
-  if KeyValueEquals(Rootkey, 'Software\Classes\InnoSetupScriptFile\DefaultIcon', SelfName + ',1') then
-    RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey, 'Software\Classes\InnoSetupScriptFile\DefaultIcon');
-  if KeyValueEquals(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\open\command', '"' + SelfName + '" "%1"') then
-    RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\open');
-  if KeyValueEquals(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\OpenWithInnoSetup\command', '"' + SelfName + '" "%1"') then
-    RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\OpenWithInnoSetup');
-  if KeyValueEquals(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\Compile\command', '"' + SelfName + '" /cc "%1"') then
-    RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\Compile');
-  RegDeleteKeyIfEmpty(rvDefault, Rootkey, 'Software\Classes\InnoSetupScriptFile\shell');
-  if KeyValueEquals(Rootkey, 'Software\Classes\InnoSetupScriptFile', 'Inno Setup Script') and
-     GetKeyNumSubkeysValues(Rootkey, 'Software\Classes\InnoSetupScriptFile', NumSubkeys, NumValues) and
-     (NumSubkeys = 0) and (NumValues <= 1) then
-    RegDeleteKey(Rootkey, 'Software\Classes\InnoSetupScriptFile');
-
-  { Clean up '.iss' }
-  if not KeyExists(Rootkey, 'Software\Classes\InnoSetupScriptFile') and
-     KeyValueEquals(Rootkey, 'Software\Classes\.iss', 'InnoSetupScriptFile') then begin
-    DeleteValue(Rootkey, 'Software\Classes\.iss', nil);
-    DeleteValue(Rootkey, 'Software\Classes\.iss', 'Content Type');
-  end;
-  RegDeleteKeyIfEmpty(rvDefault, RootKey, 'Software\Classes\.iss');
+  { Leave '.iss' as-is. Other apps may have added their own OpenWithProgids
+    values there, and Microsoft docs recommend against trying to delete the
+    key's default value (which points to a ProgID). See:
+    https://learn.microsoft.com/en-us/windows/win32/shell/fa-file-types
+  }
 
   { Remove unnecessary key set by previous versions }
   RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey,
     'Software\Classes\Applications\Compil32.exe');
-
-  if ChangeNotify then
-    SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
 end;
 
 procedure UnregisterISSFileAssociation;
 begin
-  UnregisterISSFileAssociationDo(GetRootkey, True);
+  UnregisterISSFileAssociationDo(HKEY_CURRENT_USER);
+  if IsAdminLoggedOn then
+    UnregisterISSFileAssociationDo(HKEY_LOCAL_MACHINE);
+
+  SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
 end;
 
 end.