travis-ci: check that all build artifacts are .gitignore-d

Every once in a while our explicit .gitignore files get out of sync
when our build process learns to create new artifacts, like test
helper executables, but the .gitignore files are not updated
accordingly.

Use Travis CI to help catch such issues earlier: check that there are
no untracked files at the end of any build jobs building Git (i.e. the
64 bit Clang and GCC Linux and OSX build jobs, plus the GETTEXT_POISON
and 32 bit Linux build jobs) or its documentation, and fail the build
job if there are any present.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ci/lib-travisci.sh

@@ -67,6 +67,16 @@ skip_good_tree () {
 	exit 0
 }
 
+check_unignored_build_artifacts ()
+{
+	! git ls-files --other --exclude-standard --error-unmatch \
+		-- ':/*' 2>/dev/null ||
+	{
+		echo "$(tput setaf 1)error: found unignored build artifacts$(tput sgr0)"
+		false
+	}
+}
+
 # Set 'exit on error' for all CI scripts to let the caller know that
 # something went wrong.
 # Set tracing executed commands, primarily setting environment variables

ci/run-linux32-docker.sh

@@ -23,4 +23,6 @@ docker run \
 	daald/ubuntu32:xenial \
 	/usr/src/git/ci/run-linux32-build.sh $(id -u $USER)
 
+check_unignored_build_artifacts
+
 save_good_tree

ci/run-tests.sh

@@ -8,4 +8,6 @@
 ln -s $HOME/travis-cache/.prove t/.prove
 make --quiet test
 
+check_unignored_build_artifacts
+
 save_good_tree

ci/test-documentation.sh

@@ -18,6 +18,9 @@ test -s Documentation/git.xml
 test -s Documentation/git.1
 grep '<meta name="generator" content="AsciiDoc ' Documentation/git.html
 
+rm -f stdout.log stderr.log
+check_unignored_build_artifacts
+
 # Build docs with AsciiDoctor
 make clean
 make --jobs=2 USE_ASCIIDOCTOR=1 doc > >(tee stdout.log) 2> >(tee stderr.log >&2)
@@ -26,4 +29,7 @@ sed '/^GIT_VERSION = / d' stderr.log
 test -s Documentation/git.html
 grep '<meta name="generator" content="Asciidoctor ' Documentation/git.html
 
+rm -f stdout.log stderr.log
+check_unignored_build_artifacts
+
 save_good_tree