run.bash, cmd/dist: document GO_TEST_SHORT and GO_TEST_TIMEOUT_SCALE

These environment variables affect cmd/dist, and in turn run.bash.
They exist primarily for the Go build system, but are still needed
sometimes when investigating problems. Document them in one place.

Fixes #46054.

Change-Id: I5dea2ac79b0d203d2f3c9ec2980382f62bead5cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/455517
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/run.bash b/src/run.bash
index 4f4d437365..35fa8f626c 100755
--- a/src/run.bash
+++ b/src/run.bash
@@ -13,6 +13,15 @@
 # GO_BUILDER_NAME: the name of the Go builder that's running the tests.
 # Some tests are conditionally enabled or disabled based on the builder
 # name or the builder name being non-empty.
+#
+# GO_TEST_SHORT: if set to a non-empty, false-ish string, run tests in "-short=false" mode.
+# This environment variable is an internal implementation detail between the
+# Go build system (x/build) and cmd/dist for the purpose of longtest builders,
+# and will be removed if it stops being needed. See go.dev/issue/12508.
+#
+# GO_TEST_TIMEOUT_SCALE: a non-negative integer factor to scale test timeout by.
+# Defaults to 1, or as a special case for the purpose of the Go build system (x/build),
+# defaults to 2 when GOARCH is arm, and to 4 when GOARCH is mips, mipsle, mips64, or mips64le.
 
 set -e