Cannot paste schematic from previous version(s)

[in3otd]

In the GUI we can open schematics from previous versions but when trying to paste a schematic from a previous version a "Wrong document version" error pops up.

This comes from here where the pasted schematic version needs to be the same as the current Qucs version.

To easily reproduce:

• open a schematic
• select all, copy and paste in a text document
• change the version in the first line to 0.0.18
• select all, copy and try to paste in a schematic

(could maybe reuse the first commit of #340 to ease checking)

[ra3xdh]

Yes, I know about this problem. I always use clipboard editing to allow copy-pasting between versions. This issue should not concern simple users, because they usually uses only single Qucs version. But it makes development and debugging a bit more difficult.

[felix-salfelder]

perhaps, as long as loading old schematics is not fully tested, we should warn "loading old schematic, please be careful", instead? return false seems to be entirely pointless to me.

[in3otd]

yep, I was sure this was already known, but wanted to have a remainder to fix it :grin:

Currently we load old schematics without any user warning, I think we should have the same behavior (emit warning or not) when pasting. When 0.0.19 will be out, all existing users' (vs. developers) schematics will become old.

[guitorri]

There also something about loading future versions: https://github.com/Qucs/qucs/blob/release-0.0.19/qucs/qucs/dialogs/qucssettingsdialog.cpp#L134

[in3otd]

I was trying to understand the logic of the current code about loading from future versions: at present having it checked or unchecked makes practically no difference...

• when trying to load a file from a future version, the user is always asked if ey really wants to open the file (see the code here), regardless of the related setting
• also, currently we show all the .sch files in the tree view, also from future versions, regardless of the related setting status (see the code here; n is negative for future versions but this case is not actually treated differently) This is different from the behaviour of previous versions: in 0.0.17 the files from future versions were not shown (see the code here)

So, what I propose is to modify the current behavior as:

• if load from future versions is enabled:
  • show future-version schematic in the tree view
  • open them without any warning message
  • paste from future versions without any warning message
• if load from future versions is not enabled:
  • do not show future-version schematic in the tree view
  • abort opening them (if forced thru the Open dialog) with an error message
  • abort pasting from future versions with an error message

seems reasonable ?

(Edit: moved a sentence which ended up at the end to its proper place)

[in3otd]

Fixed in #607