Fail the build if there are any errors (#663)

We used to fail when building a book resulted in any `WARNING`s or the
process the builds the book exits with a non-0 status. This was fine
when we were only using `AsciiDoc` because `a2x` would always exit with
a non-0 status if it output any `ERROR`s. But Asciidoctor will happily
exit with a 0 status after output errors! If that happens, we should
fail to build the book. This change does exectly that. And it adds an
integration test that attempt to build a file with a missing include.
That tests this change.

Author: nik9000

integtest/Makefile

@@ -14,6 +14,7 @@ check: \
 	includes_expected_files includes_same_files \
 	beta_expected_files beta_same_files \
 	experimental_expected_files experimental_same_files \
+	missing_include_fails_asciidoc missing_include_fails_asciidoctor \
 	readme_expected_files readme_same_files \
 	small_all_expected_files
 
@@ -70,10 +71,30 @@ experimental_expected_files: /tmp/experimental_asciidoc
 		./html_diff /tmp/$*_asciidoc/$$file /tmp/$*_asciidoctor/$$file; \
 	done
 
+# Build the docs into the target
 define BD=
 /docs_build/build_docs.pl --in_standard_docker --out $@
 endef
 
+# Build the docs into a temporary directory
+define BD_DUMMY=
+/docs_build/build_docs.pl --in_standard_docker --out /tmp/dummy
+endef
+
+.PHONY: missing_include_fails_asciidoc
+missing_include_fails_asciidoc: missing_include.asciidoc
+	set +e; \
+		$(BD_DUMMY) --doc missing_include.asciidoc > /tmp/out 2>&1; \
+		test $$? -eq 255
+	$(call GREP,'WARNING: missing_include.asciidoc: line 7: include file not found: /docs_build/integtest/missing.asciidoc',/tmp/out)
+
+.PHONY: missing_include_fails_asciidoctor
+missing_include_fails_asciidoctor: missing_include.asciidoc
+	set +e; \
+		$(BD_DUMMY) --asciidoctor --doc missing_include.asciidoc > /tmp/out 2>&1; \
+		test $$? -eq 255
+	$(call GREP,'ERROR: missing_include.asciidoc: line 7: include file not found: /docs_build/integtest/missing.asciidoc',/tmp/out)
+
 /tmp/readme_asciidoc: /docs_build/README.asciidoc
 	$(BD) --doc /docs_build/README.asciidoc
 
@@ -126,3 +147,18 @@ small_all_expected_files: /tmp/small_all
 
 	# Check out the files we just built
 	git clone /tmp/small_all.git /tmp/small_all
+
+define GREP=
+	# grep for a string in a file, outputting the whole file if there isn't
+	# a match.
+	[ -e $(2) ] || { \
+		echo "can't find $(2)"; \
+		ls $$(dirname $(2)); \
+		false; \
+	}
+	grep $(1) $(2) > /dev/null || { \
+		echo "Couldn't find $(1) in $(2):"; \
+		cat $(2); \
+		false; \
+	}
+endef

integtest/missing_include.asciidoc

@@ -0,0 +1,9 @@
+= Title
+
+== Chapter
+
+I include missing between here
+
+include::missing.asciidoc[]
+
+and here.

lib/ES/Util.pm

@@ -294,7 +294,7 @@ sub build_single {
 sub _check_build_error {
 #===================================
     my ( $output, $died, $lenient ) = @_;
-    my $warned = grep {/^(a2x|asciidoc(tor)?): (WARNING):/} split "\n", $output;
+    my $warned = grep {/^(a2x|asciidoc(tor)?): (WARNING|ERROR):/} split "\n", $output;
 
     return unless $died || $warned;