Fix Split edge default and block mixed slot export

[kishore08-07]

Bug fix

Fixed bug

This PR fixes #183 by improving the behavior of Split operations in the Diagram Editor to make them more intuitive, consistent, and error-resistant.

Previously:

• Split edges defaulted to keyed, making edge labeling less discoverable for users.
• The editor allowed mixed output types (keyed and sequence) from the same Split node.
• Export was not proactively blocked for this invalid Split state.

Fix applied

• Default Split edge type preference now starts with sequence.
• Added Split export validation that rejects mixed keyed and sequence outputs from the same Split source.
• Export button is disabled when mixed Split slot types exist.
• Conflicting Split edges are highlighted in error color until the mismatch is resolved.
• Added regression tests for both behaviors.

Screencast.from.2026-03-18.14-11-01.webm

GenAI Use

We follow OSRA's policy on GenAI tools

• I used a GenAI tool in this PR.
• I did not use GenAI

Generated-by:
GPT-5.3-Codex

[mxgrey]

Thanks for opening this contribution. It's great to see the community identify pain points and put forward solutions.

I'm not certain, but I suspect we're going to see merge conflicts between this and #182, so just a heads up on that.

Added Split export validation that rejects mixed keyed and sequence outputs from the same Split source.

It's actually intentional that the Split operation supports a mix of keys and sequences. See the 💡Tip in this section of the handbook. We should revert this restriction.

Export button is disabled when mixed Split slot types exist.

I think it's dangerous for us to ever completely disable the export button. There may be times when a user wants to save a file in a bad state because they want to create a backup or need to exit the program, and they want to come back later to fix it.

I think a better approach would be a pop-up warning telling the user that the workflow is in a broken state and verifying that they want to save it, similar to the warning that a Save dialog usually gives if you try to save a file with a name that is already in use. For now we should revert this disabling behavior. The pop-up warning approach (or some other way to warn the user when the diagram is in a bad state) can be added as a separate PR.

[mxgrey]

Note this error that shows up while running the unit tests:

 error: crossflow_diagram_editor@0.0.7: Frontend has changed, run `BUILD_FRONTEND=1 cargo build` to update it

You'll need to run BUILD_FRONTEND=1 cargo build then commit and push the resulting changes.

[kishore08-07]

Thanks for opening this contribution. It's great to see the community identify pain points and put forward solutions.

I'm not certain, but I suspect we're going to see merge conflicts between this and #182, so just a heads up on that.

Added Split export validation that rejects mixed keyed and sequence outputs from the same Split source.

It's actually intentional that the Split operation supports a mix of keys and sequences. See the 💡Tip in this section of the handbook. We should revert this restriction.

Export button is disabled when mixed Split slot types exist.

I think it's dangerous for us to ever completely disable the export button. There may be times when a user wants to save a file in a bad state because they want to create a backup or need to exit the program, and they want to come back later to fix it.

I think a better approach would be a pop-up warning telling the user that the workflow is in a broken state and verifying that they want to save it, similar to the warning that a Save dialog usually gives if you try to save a file with a name that is already in use. For now we should revert this disabling behavior. The pop-up warning approach (or some other way to warn the user when the diagram is in a bad state) can be added as a separate PR.

Thanks for the feedback! I’ve reverted the restriction on mixed keyed and sequential Split outputs. The export button is now always enabled, so users can save diagrams even in an intermediate/bad state.

[kishore08-07]

Note this error that shows up while running the unit tests:

 error: crossflow_diagram_editor@0.0.7: Frontend has changed, run `BUILD_FRONTEND=1 cargo build` to update it

You'll need to run BUILD_FRONTEND=1 cargo build then commit and push the resulting changes.

I have ran BUILD_FRONTEND=1 cargo build and committed the tar.gz file. Let me know if anything else is needed!

[aaronchongth]

Looks like you've reverted all the changes regarding this PR, instead of just reverting the part about the export button, and keeping just the test in the changes.

@kishore08-07 please review your (or the AI's) changes carefully before making any commits. Especially for UI related changes, please always take a quick video of changes that address any feedback specifically. This will help move the review process along.

Please note that the use of AI in this unsupervised manner is a huge security concern and is frowned upon especially in the open source community, where it may have wider implications than expected.