Equal sign "=" no longer valid in participant of sequence diagrams

[digitalmoksha]

Description

In 11.4, using an = in a participant name of a sequence diagram gives an error. This used to work in 10.7.0.

Steps to reproduce

When using 10.7.0, the graph

sequenceDiagram
   x->>y=true: Transition to true

used to work.

However now with 11.4 (haven't tested any other previous 11.x versions) it gives an error

Error: Error: Parse error on line 2:
...enceDiagram x->>y=true: Transition to
----------------------^
Expecting 'NEWLINE', 'AS', ',', 'SOLID_OPEN_ARROW', 'DOTTED_OPEN_ARROW', 'SOLID_ARROW', 'BIDIRECTIONAL_SOLID_ARROW', 'DOTTED_ARROW', 'BIDIRECTIONAL_DOTTED_ARROW', 'SOLID_CROSS', 'DOTTED_CROSS', 'SOLID_POINT', 'DOTTED_POINT', 'TXT', got 'INVALID'

This seems to be a backwards compatibility bug.

Screenshots

No response

Code Sample

https://develop.git.mermaid.live/edit#pako:eNo1jcEOwjAMQ38lynn8QCV24g_gmEvUhq2CppC2EtO0f6eV4GZbfvaOPgdBh0XeTdTLJfJinEgB4HOa5-1crYmDm7GWWGNWqBlGRooTJrHEMfSBfSCEdZUkhK7LwPYgJD16j1vN1009uoFOaLktK7o7P0t37RW4_q9_6fEFLbY1fg

Setup

• Mermaid version: 11.4
• Browser and Version: [Chrome, Edge, Firefox]: Chrome 131.0.6778.205 macOS

Suggested Solutions

No response

Additional Context

No response

[devensm267]

sequenceDiagram x->>y: Transition to true
is the corrected syntax for 11.4

but if using '=' is essential then revert to 10.7.0 temporarily.

[digitalmoksha]

but if using '=' is essential then revert to 10.7.0 temporarily.

@devensm267 does this mean there would be a fix in the works to allow the use of = in the expression?

The intent is to have y=true in the box - is that no longer supported in Mermaid? We potentially have customers using such diagrams and don't wish to break them. But they are also asking for the new 11.x capabilities. We're currently running on 10.x and trying to upgrade to 11 and one of our tests is failing.

[ajuckel]

I'll create a PR to resolve this. The current disallowal of = in a label is due to a bug when adding bidirectional arrow support, not an intentional design decision.