diff -r 27436b422886 -r a676d2d8af0d get_source.sh
--- a/get_source.sh	Mon Oct 20 23:00:27 2014 -0700
+++ b/get_source.sh	Fri Oct 24 17:04:51 2014 -0700
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright (c) 2010, 2012, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -25,9 +25,76 @@
 # questions.
 #
 
-# Get clones of all nested repositories
-sh ./common/bin/hgforest.sh clone "$@" || exit 1
+to_stderr() {
+    echo "$@" >&2
+}
+
+error() {
+    to_stderr "ERROR: $1"
+    exit ${2:-126}
+}
+
+warning() {
+    to_stderr "WARNING: $1"
+}
+
+version_field() {
+  # rev is typically omitted for minor and major releases
+  field=`echo ${1}.0 | cut -f ${2} -d .`
+  if expr 1 + $field >/dev/null 2> /dev/null; then
+    echo $field
+  else
+    echo -1
+  fi
+}
+
+# Version check
+
+# required
+reqdmajor=1
+reqdminor=4
+reqdrev=0
+
+# requested
+rqstmajor=2
+rqstminor=6
+rqstrev=3
+
+
+# installed
+hgwhere="`command -v hg`"
+if [ "x$hgwhere" = "x" ]; then
+  error "Could not locate Mercurial command"
+fi
+
+hgversion="`hg --version 2> /dev/null | sed -n -e 's@^Mercurial Distributed SCM (version \([^+]*\).*)\$@\1@p'`"
+if [ "x${hgversion}" = "x" ] ; then
+  error "Could not determine Mercurial version of $hgwhere"
+fi
+
+hgmajor="`version_field $hgversion 1`"
+hgminor="`version_field $hgversion 2`"
+hgrev="`version_field $hgversion 3`"
+
+if [ $hgmajor -eq -1 -o $hgminor -eq -1 -o $hgrev -eq -1 ] ; then
+  error "Could not determine Mercurial version of $hgwhere from \"$hgversion\""
+fi
+
+
+# Require
+if [ $hgmajor -lt $reqdmajor -o \( $hgmajor -eq $reqdmajor -a $hgminor -lt $reqdminor \) -o \( $hgmajor -eq $reqdmajor -a $hgminor -eq $reqdminor -a $hgrev -lt $reqdrev \) ] ; then
+  error "Mercurial version $reqdmajor.$reqdminor.$reqdrev or later is required. $hgwhere is version $hgversion"
+fi
+
+
+# Request
+if [ $hgmajor -lt $rqstmajor -o \( $hgmajor -eq $rqstmajor -a $hgminor -lt $rqstminor \) -o \( $hgmajor -eq $rqstmajor -a $hgminor -eq $rqstminor -a $hgrev -lt $rqstrev \) ] ; then
+  warning "Mercurial version $rqstmajor.$rqstminor.$rqstrev or later is recommended. $hgwhere is version $hgversion"
+fi
+
+
+# Get clones of all absent nested repositories (harmless if already exist)
+sh ./common/bin/hgforest.sh clone "$@" || exit $?
 
 # Update all existing repositories to the latest sources
 sh ./common/bin/hgforest.sh pull -u
-