[githooks] CI scripts pipe failures to stderr (#1300)

Previously, some scripts had output which would only be generated on
failure, but this output was passed to stdout, which `githooks/pre-push`
pipes to `/dev/null`. In this commit, any such output is unconditionally
redirected to `stderr` - if there's any output, we want to see it. This
previously resulted in very opaque errors during `git push`, which
should be addressed by this commit.

Also, in #728, we added `ci/check_all_toolchains_tested.sh`, but didn't
add it to `githooks/pre-push`. In this commit, we fix that, and also add
a test to `githooks/pre-push` to validate that all scripts in `ci/*` at
least show up in `githooks/pre-push` by name. This isn't a foolproof
check, but it should catch obvious errors.

ci/check_all_toolchains_tested.sh

@@ -22,4 +22,4 @@ diff \
     sort -u | grep -v '^\(msrv\|stable\|nightly\)$') \
   <(cargo metadata -q --format-version 1 | \
     jq -r ".packages[] | select(.name == \"zerocopy\").metadata.\"build-rs\" | keys | .[]" | \
-    sort -u)
+    sort -u) >&2

ci/check_fmt.sh

@@ -15,4 +15,4 @@ if [[ -z $files ]]
 then
 	exit 1
 fi
-rustfmt --check $files
+rustfmt --check $files >&2

ci/check_job_dependencies.sh

@@ -30,6 +30,6 @@ jobs=$(for i in $(find .github -iname '*.yaml' -or -iname '*.yml')
 if [ -n "$jobs" ]
 then
   missing_jobs="$(echo "$jobs" | tr ' ' '\n')"
-  echo "all-jobs-succeed missing dependencies on some jobs: $missing_jobs" | tee -a $GITHUB_STEP_SUMMARY
+  echo "all-jobs-succeed missing dependencies on some jobs: $missing_jobs" | tee -a $GITHUB_STEP_SUMMARY >&2
   exit 1
 fi

ci/check_readme.sh

@@ -15,5 +15,5 @@ set -eo pipefail
 # suppress all errors from it.
 cargo install -q cargo-readme --version 3.2.0
 
-diff <(cargo -q run --manifest-path tools/Cargo.toml -p generate-readme) README.md
+diff <(cargo -q run --manifest-path tools/Cargo.toml -p generate-readme) README.md >&2
 exit $?

githooks/pre-push

@@ -14,11 +14,12 @@ echo "Running pre-push git hook: $0"
 # `cargo fmt` is useful (and the good stuff is not delivered by stderr).
 #
 # Background all jobs and wait for them so they can run in parallel.
-./ci/check_fmt.sh                         & FMT_PID=$!
-./ci/check_job_dependencies.sh >/dev/null & JOB_DEPS_PID=$!
-./ci/check_msrv.sh             >/dev/null & MSRV_PID=$!
-./ci/check_readme.sh           >/dev/null & README_PID=$!
-./ci/check_versions.sh         >/dev/null & VERSIONS_PID=$!
+./ci/check_fmt.sh                              & FMT_PID=$!
+./ci/check_all_toolchains_tested.sh >/dev/null & TOOLCHAINS_PID=$!
+./ci/check_job_dependencies.sh      >/dev/null & JOB_DEPS_PID=$!
+./ci/check_msrv.sh                  >/dev/null & MSRV_PID=$!
+./ci/check_readme.sh                >/dev/null & README_PID=$!
+./ci/check_versions.sh              >/dev/null & VERSIONS_PID=$!
 
 # `wait <pid>` exits with the same status code as the job it's waiting for.
 # Since we `set -e` above, this will have the effect of causing the entire
@@ -27,7 +28,20 @@ echo "Running pre-push git hook: $0"
 # jobs, it exits with code 0 even if one of the backgrounded jobs does not, so
 # we can't use it here.
 wait $FMT_PID
+wait $TOOLCHAINS_PID
 wait $JOB_DEPS_PID
 wait $MSRV_PID
 wait $README_PID
 wait $VERSIONS_PID
+
+# Ensure that this script calls all scripts in `ci/*`. This isn't a foolproof
+# check since it just checks for the string in this script (e.g., it could be in
+# a comment, which would trigger a false positive), but it should catch obvious
+# errors. Also note that this entire hook is a nice-to-have - failures that
+# aren't caught here will still be caught in CI.
+#
+# This was added because, in #728, we added `ci/check_all_toolchains_tested.sh`
+# without calling it from this script.
+for f in ./ci/*; do
+    grep "$f" githooks/pre-push >/dev/null || { echo "$f not called from githooks/pre-push" >&2 ; exit 1; }
+done