tcwg_gnu-build.sh: Optimize reducing regressions down to components

Change-Id: I03bcd0760a6141d971e68604c950d0cc6f94fb24

1 files changed, 28 insertions, 0 deletions

diff --git a/tcwg_gnu-build.sh b/tcwg_gnu-build.sh
index 3dd7cb89..784d425e 100755
--- a/tcwg_gnu-build.sh
+++ b/tcwg_gnu-build.sh
@@ -194,6 +194,34 @@ no_regression_p ()
     )
 }
 
+# Implement rr[breakup_updated_components] hook.
+tcwg_gnu_breakup_updated_components ()
+{
+    (
+    set -euf -o pipefail
+
+    local cc=""
+    case "${rr[ci_project]}" in
+	*_check_*)
+	    # Changes to "foo" of check_foo projects tend to cause the most
+	    # regressions.
+	    # Breakup updated components into "foo" and the rest of components
+	    # to reduce the number of builds.
+	    cc=$(echo "${rr[ci_project]}" | sed -e "s/.*_check_\(.*\)/\1/")
+	    ;;
+    esac
+
+    if print_updated_components "\n" | grep -q "^$cc\$"; then
+	echo "$cc"
+	print_updated_components "\n" | grep -v "^$cc\$" | tr '\n' ' ' | sed -e "s/ \$//g"
+	echo
+    else
+	print_updated_components "\n"
+    fi
+    )
+}
+rr[breakup_updated_components]=tcwg_gnu_breakup_updated_components
+
 run_step stop_on_fail -10 reset_artifacts
 run_step stop_on_fail x prepare_abe
 case "${rr[ci_project]}" in