Update Blockly.Msg system to work without reinjecting the workspace

[AnmAtAnm]

Problem statement

If Blockly.Msg is updated without refreshing the page, new blocks with dropdown fields do not reflect updates.

Expected Behavior

New blocks (with new Field instances) should reflect the latest version of Blockly.Msg. This should allow an app to save a workspace to XML, update the Blockly.Msg string table (i.e., load a new language localization), and reload the workspace from XML with the string changes / language updates.

Actual Behavior

Dropdowns in new blocks retain the Msg string from the time the first block is defined.

Steps to Reproduce

TODO: We have no easy framework that demonstrates live updates to Blockly.Msg.

1. Create block with a dropdown that contains a static options list of %{BKY_...} strings (e.g., logic_boolean).
2. Update one of the referenced strings in Blockly.Msg (e.g., Blockly.Msg.LOGIC_BOOLEAN_TRUE = 'Hello!').
3. Create a new instance of the block. Note the option sting label has not changed in the dropdown UI.

Compare how other fields respond. For instance, load a not block after Blockly.Msg.LOGIC_NEGATE_TITLE = "Hello %1"

[AnmAtAnm]

This is specific to blocks defined using the JSON notation and use the JSON defined static list of dropdown options.

[jobsFu]

Does that work out ？/
When I use the web version with vue, I will use i18n instead of refresh to switch languages.

[BeksOmega]

Some possible solutions:

1. Revamp the Blockly.Msg system. I think there might be a plan to do this anyway to provide more support for translatable text in plugins?
2. Change the dropdown field to always somewhat-dynamically generate options. So instead of only replacing message references once in the trimOptions_ method, we would do it every time the dropdown is opened.
3. Revert all core blocks that use dropdowns to JavaScript definitions. The issue would still exist, but at least not with core blocks.

Does anyone have an opinion about which solution they think is best? (or other possible solutions =)

[maribethb]

This is something we've discussed fixing as a team, but we would want to fix it generally and not just put a bandaid on for dropdowns. I updated the title of this bug since it already has good context and a workaround we can refer to in the meantime.