Remove Go cache on failure.

It's unclear why permissions wind up corrupted, but these can be cleared
on any failure, similar to the bazel cache itself:
  https://buildkite.com/gvisor/pipeline/builds/2304#_

PiperOrigin-RevId: 355057421

2 files changed, 16 insertions, 7 deletions

diff --git a/.buildkite/hooks/post-command b/.buildkite/hooks/post-command
index 8af1369a6..c4c6fc90c 100644
--- a/.buildkite/hooks/post-command
+++ b/.buildkite/hooks/post-command
@@ -51,6 +51,9 @@ if test "${BUILDKITE_COMMAND_EXIT_STATUS}" -ne "0"; then
   # Attempt to clear the cache and shut down.
   make clean || echo "make clean failed with code $?"
   make bazel-shutdown || echo "make bazel-shutdown failed with code $?"
+  # Attempt to clear any Go cache.
+  sudo rm -rf "${HOME}/.cache/go-build"
+  sudo rm -rf "${HOME}/go"
 fi
 
 # Kill any running containers (clear state).
diff --git a/tools/go_branch.sh b/tools/go_branch.sh
index 026733d3c..e89a8b098 100755
--- a/tools/go_branch.sh
+++ b/tools/go_branch.sh
@@ -16,14 +16,25 @@
 
 set -xeou pipefail
 
+# Remember our current directory.
+declare orig_dir
+orig_dir=$(pwd)
+readonly orig_dir
+
+# Record the current working commit.
+declare head
+head=$(git describe --always)
+readonly head
+
 # Create a temporary working directory, and ensure that this directory and all
 # subdirectories are cleaned up upon exit.
 declare tmp_dir
 tmp_dir=$(mktemp -d)
 readonly tmp_dir
 finish() {
-  cd / # Leave tmp_dir.
-  rm -rf "${tmp_dir}"
+  cd "${orig_dir}"          # Leave tmp_dir.
+  rm -rf "${tmp_dir}"       # Remove all contents.
+  git checkout -f "${head}" # Restore commit.
 }
 trap finish EXIT
 
@@ -70,11 +81,6 @@ declare -r go_merged="${tmp_dir}/merged"
 rsync --recursive "${go_amd64}/" "${go_merged}"
 rsync --recursive "${go_arm64}/" "${go_merged}"
 
-# Record the current working commit.
-declare head
-head=$(git describe --always)
-readonly head
-
 # We expect to have an existing go branch that we will use as the basis for this
 # commit. That branch may be empty, but it must exist. We search for this branch
 # using the local branch, the "origin" branch, and other remotes, in order.