From e6cf8ac2c3c270a3a654a1f2feb3227576100d6b Mon Sep 17 00:00:00 2001 From: Robert Pajak Date: Fri, 26 Jun 2026 07:28:35 +0200 Subject: [PATCH] Clarify case-insensitive env carrier lookup --- specification/context/env-carriers.md | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/specification/context/env-carriers.md b/specification/context/env-carriers.md index dd03bc2bab8..eba968f7bc9 100644 --- a/specification/context/env-carriers.md +++ b/specification/context/env-carriers.md @@ -98,6 +98,13 @@ environment-specific `Get` operation MUST normalize the requested key to read a non-normalized environment variable named `x-b3-traceid`, even though that name normalizes to `X_B3_TRACEID`. +> [!NOTE] +> On platforms with case-insensitive environment variable lookup, such as +> Windows, the platform lookup performed by `Get` may match an environment +> variable whose name differs from the normalized key only by case. For example, +> if a Windows process environment contains `traceparent`, reading the +> normalized key `TRACEPARENT` may return the value of `traceparent`. + > [!NOTE] > This normalization is consistent with the environment variable naming rules > defined in [POSIX.1-2024](https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap08.html).