restrict baggage key further

Author: gruebel

opentelemetry/CHANGELOG.md

@@ -13,7 +13,7 @@
   - Align `Baggage.remove()` signature with `.get()` to take the key as a reference
   - `Baggage` can't be retrieved from the `Context` directly anymore and needs to be accessed via `context.baggage()`
   - `with_baggage()` and `current_with_baggage()` override any existing `Baggage` in the `Context`
-  - `Baggage` keys can't be empty and don't allow `"(),/:;<=>?@[\]{}` chars (see [RFC7230, Section 3.2.6](https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6))
+  - `Baggage` keys can't be empty and only allow ASCII visual chars, except `"(),/:;<=>?@[\]{}` (see [RFC7230, Section 3.2.6](https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6))
 - Changed `Context` to use a stack to properly handle out of order dropping of `ContextGuard`. This imposes a limit of `65535` nested contexts on a single thread. See #[2378](https://github.com/open-telemetry/opentelemetry-rust/pull/2284) and #[1887](https://github.com/open-telemetry/opentelemetry-rust/issues/1887).
 - Added additional `name: Option<&str>` parameter to the `event_enabled` method
   on the `Logger` trait. This allows implementations (SDK, processor, exporters)

opentelemetry/src/baggage.rs

@@ -230,7 +230,7 @@ impl Baggage {
         !key.is_empty()
             && key
                 .iter()
-                .all(|b| b.is_ascii() && !INVALID_ASCII_KEY_CHARS.contains(b))
+                .all(|b| b.is_ascii_graphic() && !INVALID_ASCII_KEY_CHARS.contains(b))
     }
 }