Introduce commit-script-check.sh

This script can be used to verify scripted diff commits

contrib/devtools/commit-script-check.sh

@@ -0,0 +1,46 @@
+#!/bin/sh
+# Copyright (c) 2017 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+# This simple script checks for commits beginning with: scripted-diff:
+# If found, looks for a script between the lines -BEGIN VERIFY SCRIPT- and
+# -END VERIFY SCRIPT-. If no ending is found, it reads until the end of the
+# commit message.
+
+# The resulting script should exactly transform the previous commit into the current
+# one. Any remaining diff signals an error.
+
+if test "x$1" = "x"; then
+    echo "Usage: $0 <commit>..."
+    exit 1
+fi
+
+RET=0
+PREV_BRANCH=`git name-rev --name-only HEAD`
+PREV_HEAD=`git rev-parse HEAD`
+for i in `git rev-list --reverse $1`; do
+    if git rev-list -n 1 --pretty="%s" $i | grep -q "^scripted-diff:"; then
+        git checkout --quiet $i^ || exit
+        SCRIPT="`git rev-list --format=%b -n1 $i | sed '/^-BEGIN VERIFY SCRIPT-$/,/^-END VERIFY SCRIPT-$/{//!b};d'`"
+        if test "x$SCRIPT" = "x"; then
+            echo "Error: missing script for: $i"
+            echo "Failed"
+            RET=1
+        else
+            echo "Running script for: $i"
+            echo "$SCRIPT"
+            eval "$SCRIPT"
+            git --no-pager diff --exit-code $i && echo "OK" || (echo "Failed"; false) || RET=1
+        fi
+        git reset --quiet --hard HEAD
+     else
+        if git rev-list "--format=%b" -n1 $i | grep -q '^-\(BEGIN\|END\)[ a-zA-Z]*-$'; then
+            echo "Error: script block marker but no scripted-diff in title"
+            echo "Failed"
+            RET=1
+        fi
+    fi
+done
+git checkout --quiet $PREV_BRANCH 2>/dev/null || git checkout --quiet $PREV_HEAD
+exit $RET