Meta/basecheck: validate the synthetic base of topics

diff --git a/basecheck.sh b/basecheck.sh
new file mode 100755 (executable)
index 0000000..6ca58bc
--- /dev/null
+++ b/basecheck.sh
@@ -0,0 +1,51 @@
+#!/bin/sh
+
+if test $# = 3
+then
+       merge=$1 base=$2 target=$3
+       label=$(git log --oneline -1 "$merge")
+
+       base0=$(git rev-parse "$base^0") &&
+       base1=$(git rev-parse "$merge^2") &&
+       test "$base0" = "$base1" || {
+               echo >&2 "BAD: stale $base in $target"
+               exit 2
+       }
+
+       cd ../git.one || exit 1
+       if grep "$merge" :basecheck-tested-ok >/dev/null
+       then
+               exit 0
+       elif grep "$merge" :basecheck-tested-ng >/dev/null
+       then
+               echo >&2 "BAD (again): $label"
+               exit 1
+       fi
+
+       echo >&2 "Testing $merge $target"
+       git reset --quiet --hard "$merge" || exit 1
+       if Meta/Make -s -j32 >:basecheck-errors 2>&1
+       then
+               echo >&2 "OK: $label"
+               echo "$merge" >>:basecheck-tested-ok
+               exit 0
+       else
+               echo "$merge" >>:basecheck-tested-ng
+               cat ":basecheck-errors"
+               echo >&2 "BAD: $label"
+               exit 1
+       fi
+
+       exit 0 ;# just in case
+fi
+
+git log --oneline --abbrev=-1 --min-parents=2 ..seen |
+sed -n -e "s|^\([0-9a-f]*\) Merge branch '\(.*\)' into \(../..*\)$|\1 \2 \3|p" |
+{
+       exit=
+       while read merge base target
+       do
+               "$0" "$merge" "$base" "$target" </dev/null || exit=$?
+       done
+       exit $exit
+}