add script to validate nothing was changed that needed to re-run go generate

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

scripts/.validate

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+if [ -z "$VALIDATE_UPSTREAM" ]; then
+	# this is kind of an expensive check, so let's not do this twice if we
+	# are running more than one validate bundlescript
+
+	VALIDATE_REPO='https://github.com/cloudflare/redoctober.git'
+	VALIDATE_BRANCH='master'
+
+	if [ "$TRAVIS" = 'true' -a "$TRAVIS_PULL_REQUEST" != 'false' ]; then
+		VALIDATE_REPO="https://github.com/${TRAVIS_REPO_SLUG}.git"
+		VALIDATE_BRANCH="${TRAVIS_BRANCH}"
+	fi
+
+	VALIDATE_HEAD="$(git rev-parse --verify HEAD)"
+
+	git fetch -q "$VALIDATE_REPO" "refs/heads/$VALIDATE_BRANCH"
+	VALIDATE_UPSTREAM="$(git rev-parse --verify FETCH_HEAD)"
+
+	VALIDATE_COMMIT_LOG="$VALIDATE_UPSTREAM..$VALIDATE_HEAD"
+	VALIDATE_COMMIT_DIFF="$VALIDATE_UPSTREAM...$VALIDATE_HEAD"
+
+	validate_diff() {
+		if [ "$VALIDATE_UPSTREAM" != "$VALIDATE_HEAD" ]; then
+			git diff "$VALIDATE_COMMIT_DIFF" "$@"
+		fi
+	}
+	validate_log() {
+		if [ "$VALIDATE_UPSTREAM" != "$VALIDATE_HEAD" ]; then
+			git log "$VALIDATE_COMMIT_LOG" "$@"
+		fi
+	}
+fi

scripts/validate-html-generation

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+source "${DIR}/.validate"
+
+IFS=$'\n'
+files=( $(validate_diff --diff-filter=ACMR --name-only -- 'static/index.html' || true) )
+unset IFS
+
+if [ ${#files[@]} -gt 0 ]; then
+	# We run go generate to and see if we have a diff afterwards
+	go generate >/dev/null
+	# Let see if the working directory is clean
+	diffs="$(git status --porcelain -- static.go 2>/dev/null)"
+	if [ "$diffs" ]; then
+		{
+			echo 'The result of go generate differs'
+			echo
+			echo "$diffs"
+			echo
+			echo 'Please re-run go generate'
+			echo
+		} >&2
+		false
+	else
+		echo 'Congratulations! File generation is done correctly.'
+	fi
+fi