I am running Windows 10 Home 64 bit 22H2 19045.6216 using a pre-compiled version of graphviz downloaded from graphviz.org.
The following dot file is accepted by graphviz version 12.2.1 (20241206.2353)
but fails with a syntax error with graphviz version 13.1.2 (20250808.2320).
By changing the label from <> to < > (an extra space) it will be accepted in v13. I am not able to simplify the dot file any further. For example, removing the fontsize property causes it to fail with both v12 and v13.
This is annoying because it means that all the graphviz files I have distributed to others will not work with the most recent version.
Is this change in behavior intentional so that html tags do not allow empty content models in the xml/schema sense ? IIRC adding the extra space changes the content model from “empty” to “simple content”. If this is the case, I would not expect omitting the fontsize property to change the behavior.
digraph "my-digraph"
{
// Windows 10 Home 64 bit 22H2 19045.6216
//
// syntax error with dot - graphviz version 13.1.2 (20250808.2320)
// passes with dot - graphviz version 12.2.1 (20241206.2353)
"my-label" [fontsize=16 label=<label-with-fontsize>]
"empty-label" [label=<>]
}
The error message from v13 is: Error: syntax error in line 1 ... <HTML></HTML> ... in label of node empty-label