Allow outputting the progress of Bazel's build.

Rename run_silent to run and add a global VERBOSE variable that tunes
whether the run function prints its output or not.

This is for better debugging possibilities of Bazel's self-build, though
compile.sh remains silent as before and only displays the command's output
in case of an error.

--
MOS_MIGRATED_REVID=115599355

compile.sh

@@ -24,6 +24,11 @@ set -o errexit
 
 cd "$(dirname "$0")"
 
+# Set the default verbose mode in buildenv.sh so that we do not display command
+# output unless there is a failure.  We do this conditionally to offer the user
+# a chance of overriding this in case they want to do so.
+: ${VERBOSE:=no}
+
 source scripts/bootstrap/buildenv.sh
 
 function usage() {

scripts/bootstrap/bootstrap.sh

@@ -79,9 +79,9 @@ function bootstrap_test() {
   local BAZEL_SUM=$2
   local BAZEL_TARGET=${3:-src:bazel}
   [ -x "${BAZEL_BIN}" ] || fail "syntax: bootstrap bazel-binary"
-  run_silent ${BAZEL_BIN} --nomaster_bazelrc --bazelrc=${BAZELRC} clean \
+  run ${BAZEL_BIN} --nomaster_bazelrc --bazelrc=${BAZELRC} clean \
       --expunge || return $?
-  run_silent ${BAZEL_BIN} --nomaster_bazelrc --bazelrc=${BAZELRC} build \
+  run ${BAZEL_BIN} --nomaster_bazelrc --bazelrc=${BAZELRC} build \
       ${EXTRA_BAZEL_ARGS-} \
       --strategy=Javac=worker --worker_quit_after_build \
       --fetch --nostamp \

scripts/bootstrap/buildenv.sh

@@ -43,6 +43,11 @@ msys*|mingw*)
   EXE_EXT=".exe"
 esac
 
+# Whether we display build messages or not.  We set this conditionally because
+# the file including us or the user may already have defined VERBOSE to their
+# liking.
+: ${VERBOSE:=yes}
+
 # List of functions to invoke on exit.
 ATEXIT_HANDLERS=
 
@@ -109,12 +114,24 @@ eval "cleanup_phasefile() {
       }"
 atexit cleanup_phasefile
 
-function run_silent() {
-  echo "${@}" >${errfile}
-  # TODO(kchodorow): figure out why this doesn't exit on a non-zero exit code,
-  # even though errexit is set.
-  "${@}" >>${errfile} 2>&1 || exit $?
-  rm ${errfile}
+# Excutes a command respecting the current verbosity settings.
+#
+# If VERBOSE is yes, the command itself and its output are printed.
+# If VERBOSE is no, the command's output is only displayed in case of failure.
+#
+# Exits the script if the command fails.
+function run() {
+  if [ "${VERBOSE}" = yes ]; then
+    echo "${@}"
+    "${@}" || exit $?
+  else
+    echo "${@}" >"${errfile}"
+    # The exit here is needed because "set -e" on the shell does not cause
+    # errors in functions to exit in all cases.  We should probably disable
+    # "set -e" altogether and add explicit error handling where necessary.
+    "${@}" >>"${errfile}" 2>&1 || exit $?
+    rm "${errfile}"
+  fi
 }
 
 function fail() {

scripts/bootstrap/compile.sh

@@ -125,13 +125,13 @@ function java_compilation() {
     cat "$paramfile" >&2
   fi
 
-  run_silent "${JAVAC}" -classpath "${classpath}" -sourcepath "${sourcepath}" \
+  run "${JAVAC}" -classpath "${classpath}" -sourcepath "${sourcepath}" \
       -d "${output}/classes" -source "$JAVA_VERSION" -target "$JAVA_VERSION" \
       -encoding UTF-8 "@${paramfile}"
 
   log "Extracting helper classes for $name..."
   for f in ${library_jars} ; do
-    run_silent unzip -qn ${f} -d "${output}/classes"
+    run unzip -qn ${f} -d "${output}/classes"
   done
 }
 
@@ -151,13 +151,13 @@ function create_deploy_jar() {
 
   log "Creating $name.jar..."
   echo "Main-Class: $mainClass" > $output/MANIFEST.MF
-  run_silent "$JAR" cmf $output/MANIFEST.MF $output/$name.jar $packages "$@"
+  run "$JAR" cmf $output/MANIFEST.MF $output/$name.jar $packages "$@"
 }
 
 if [ -z "${BAZEL_SKIP_JAVA_COMPILATION}" ]; then
   log "Compiling Java stubs for protocol buffers..."
   for f in $PROTO_FILES ; do
-    run_silent "${PROTOC}" -Isrc/main/protobuf/ --java_out=${OUTPUT_DIR}/src "$f"
+    run "${PROTOC}" -Isrc/main/protobuf/ --java_out=${OUTPUT_DIR}/src "$f"
   done
 
   java_compilation "Bazel Java" "$DIRS" "$LIBRARY_JARS" "${OUTPUT_DIR}"