Let TravisCI automatically rebuild README.md when pushing

.travis.yml

@@ -0,0 +1,17 @@
+sudo: false
+
+services:
+  - docker
+
+env:
+  global:
+    - secure: "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"
+
+install:
+  - true
+
+script:
+  - if test "${TRAVIS_EVENT_TYPE:-}" = 'push'; then ./scripts/travisci-update-readme; fi
+
+notifications:
+  email: false

scripts/common

@@ -26,3 +26,29 @@ stringInList () {
 	done
 	return 1
 }
+
+# Return the strings that are present in two space-separated strings
+#
+# Arguments:
+# $1: the first space-separated string
+# $2: the first second-separated string
+#
+# Output:
+# The space-separated list of strings that are present in both lists
+commonElements () {
+	commonElements_result=''
+	resetIFS
+	for commonElements_inA in ${1}
+	do
+		if stringInList "${commonElements_inA}" "${2}"
+		then
+			if test -z "${commonElements_result}"
+			then
+				commonElements_result="${commonElements_inA}"
+			else
+				commonElements_result="${commonElements_result} ${commonElements_inA}"
+			fi
+		fi
+	done
+	echo "${commonElements_result}"
+}

scripts/travisci-update-readme

@@ -0,0 +1,77 @@
+#!/bin/sh
+
+# Let's set a sane environment
+set -o errexit
+set -o nounset
+
+UPDATE_README_COMMIT_AUTHOR_NAME='Travis CI'
+UPDATE_README_COMMIT_AUTHOR_EMAIL='michele@locati.it'
+UPDATE_README_COMMIT_MESSAGE='Automatically update README.md'
+WATCHED_FILES='data/special-requirements data/supported-extensions scripts/common scripts/update-readme scripts/travisci-update-readme'
+
+
+echo 'Checking environment'
+if test -z "${TRAVIS_BUILD_DIR:-}" -o -z "${TRAVIS_BRANCH:-}" -o -z "${TRAVIS_EVENT_TYPE:-}" -o -z "${TRAVIS_REPO_SLUG:-}"
+then
+	echo 'Not in a TravisCI environment' >&2
+	exit 1
+fi
+if test -z "${GUTHUB_ACCESS_TOKEN:-}"
+then
+	
+	echo 'GitHub access token not set' >&2
+	# To create it:
+	#  - go to https://github.com/settings/tokens/new?scopes=repo
+	#  - create a new token
+	#  - sudo apt install -y build-essential ruby ruby-dev
+	#  - sudo gem install travis
+	#  - travis encrypt -r <owner>/<repo> GUTHUB_ACCESS_TOKEN=<TOKEN>
+	#  - Add to .travis.yml:
+	#    env:
+	#      global:
+	#        - secure: "encrypted string"
+	exit 1
+fi
+if test "${TRAVIS_EVENT_TYPE}" != 'push'
+then
+	echo 'This script should only be run in push builds' >&2
+	exit 1
+fi
+
+LAST_AUTO_UPDATED_IN="$(git -C "${TRAVIS_BUILD_DIR}" rev-list --max-count 1 --author "<${UPDATE_README_COMMIT_AUTHOR_EMAIL}>" --grep "${UPDATE_README_COMMIT_MESSAGE}" "${TRAVIS_BRANCH}")"
+if test -z "${LAST_AUTO_UPDATED_IN}"
+then
+	printf 'Rebuild of README.md enabled (no previous automatic refresh of it in branch %s)\n' "${TRAVIS_BRANCH}"
+else
+	MODIFIED_FILES_SINCE="$(git -C "${TRAVIS_BUILD_DIR}" diff --name-only "${LAST_AUTO_UPDATED_IN}...${TRAVIS_BRANCH}")"
+	if test -z "$(commonElements "${WATCHED_FILES}" "${MODIFIED_FILES_SINCE}")"
+	then
+		printf 'Rebuild of README.md not needed (no relevant files changed in branch %s since commit %s)\n' "${TRAVIS_BRANCH}" "${LAST_AUTO_UPDATED_IN}"
+		exit 0
+	fi
+	printf 'Rebuild of README.md enabled (relevant files changed in branch %s since commit %s)\n' "${TRAVIS_BRANCH}" "${LAST_AUTO_UPDATED_IN}"
+fi
+
+echo 'Updating README.md'
+"${TRAVIS_BUILD_DIR}/scripts/update-readme"
+set -x
+if test -z "$(git -C "${TRAVIS_BUILD_DIR}" ls-files -m | grep -E '^README\.md$')"
+then
+	echo 'README.md has not been changed'
+	exit 0
+fi
+
+echo 'Committing changes to README.md'
+git -C "${TRAVIS_BUILD_DIR}" config user.name "${UPDATE_README_COMMIT_AUTHOR_NAME}"
+git -C "${TRAVIS_BUILD_DIR}" config user.email "${UPDATE_README_COMMIT_AUTHOR_EMAIL}"
+git -C "${TRAVIS_BUILD_DIR}" add README.md
+git -C "${TRAVIS_BUILD_DIR}" commit -m "${UPDATE_README_COMMIT_MESSAGE}"
+
+printf 'Adding %s remote\n' "${TRAVIS_REPO_SLUG}"
+git remote add deploy "https://${GUTHUB_ACCESS_TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git"
+
+printf 'Pushing to %s\n' "${TRAVIS_REPO_SLUG}"
+git push deploy "${TARGET_BRANCH}"
+git -C "${TRAVIS_BUILD_DIR}" push add deploy "https://${GUTHUB_ACCESS_TOKEN}@github.com/${TRAVIS_REPO_SLUG}.git"
+
+echo 'Done.'