> This page is for Fern CLI.

> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://buildwithfern.com/learn/llms.txt.

## 5.170.5

**`(fix):`** The v3 OpenAPI parser no longer crashes with `Maximum call stack size exceeded` on a
discriminated union that contains itself as a variant (for example a `Branch` whose
`parts` are a `Leaf` or another `Branch`) when the variants declare the discriminant property.

**`(fix):`** `fern generate --docs` and `fern docs dev` now log a warning when the v3 OpenAPI parser fails
and the API Reference falls back to the v2 parser, instead of falling back silently.

**`(fix):`** The v3 OpenAPI parser now honors `respect-per-spec-base-path`. Each spec's plain
`x-fern-base-path` is applied to that spec's endpoint paths, so it is no longer dropped
when `generators.yml` lists more than one spec (for example in docs API Reference URLs).
Set the option on every spec that has a base path: a spec without it still uses the API-wide
base path, and only one spec's API-wide base path is kept when specs are merged. A base path
with path parameters keeps the API-wide behavior and now logs a warning.

## 5.170.4

**`(fix):`** `fern sdk migrate` carries a Fern Python generator's `stream_abstraction` setting over to the target's
`generation.streamAbstraction` instead of reporting it as unsupported and dropping it. Bumps
`@postman/sdk-config` to 0.15.0.