This tool, and libopenapi respectively, cannot (to my knowledge) handle a very common case, which is:

• define an OpenAPI schema with external references (pointing to local files relative to the schema file)
• push that schema
• remove any of the $ref'ed schemas from the repo and push the new changes
• do any changes afterwards that do not bring back this $ref file from the past

Whenever openapi-changes checks the git history and compares file changes there will always be this error:

https://github.com/pb33f/libopenapi/blob/1f17c502e78acf5984a49a3459fcc37ce316c0c8/index/find_component.go#L161

I tried --ext-refs and -p with different path combinations, no success.

I'd contribute to the project, but Go is not my lang of expertise and I also read @daveshanley is rewriting it.

Here is a sample project that perfectly demonstrates the issue in its simplest form:
openapi-changes-ref-bug.zip

• unzip the folder
• cd into it
• execute openapi-changes html-report . openapi.yaml
• also try `openapi-changes html-report --ext-refs -p . . openapi.yaml