Support old version state machine designer artifacts

[ptyin]

Why you need it?

New version state machine designer uses JSON with style information that is great similar to the user-written JSON. However, the JSON file that old version (i.e., the one implemented in GGEditor) is in a very different form. The new version should be backward-compatible.

How it could be?

Extend SagaImporter to be backward-compatible.

Other related information

Please merge related PR to the refactor_designer branch.

[elysium-w]

@ptyin I would like to work on this issue. Could you please assign it to me?

[ptyin]

@ptyin I would like to work on this issue. Could you please assign it to me?

Sure. You can first shed some lights on it (how would you like to design and test), and then work on implementation.

[elysium-w]

@ptyin I would like to work on this issue. Could you please assign it to me?

Sure. You can first shed some lights on it (how would you like to design and test), and then work on implementation.

My idea might be simpler. Add a converter function that checks whether the JSON is in the old version format. If so, convert it to the new version format.
And I want to know,how many versions before?Which version of Seata uses the old JSON format?

[ptyin]

@ptyin I would like to work on this issue. Could you please assign it to me?

Sure. You can first shed some lights on it (how would you like to design and test), and then work on implementation.

My idea might be simpler. Add a converter function that checks whether the JSON is in the old version format. If so, convert it to the new version format. And I want to know,how many versions before?Which version of Seata uses the old JSON format?

There is a breaking change on the designer introduced by the following PR,

• feature: full support for states in the refactored state machine designer #6169

The old JSON format indicates the one before this PR. So what you should concern about is the one. You can checkout the 2.0.0 branch to see the older version,

https://github.com/apache/incubator-seata/tree/2.0.0/saga/seata-saga-statemachine-designer