Add logging of asciidoc/-tor errors

Add logging of the errors which asciidoc and asciidoctor output to their
stderr stream when converting asciidoc documents. Note that
asciidoctor's exit code may be SUCCESS even if there are ERROR messages
in its stderr output (tested with Asciidoctor 0.1.4 and 1.5.5).
Therefore log the stderr output whenever it is non-empty.

See #2399

diff --git a/helpers/content.go b/helpers/content.go
index afefb604d5aae9e57688a4278ffefb3079798d8d..f2909f20838a0612226914c081f02fa8c3ebabe8 100644 (file)
--- a/helpers/content.go
+++ b/helpers/content.go
@@ -546,9 +546,19 @@ func getAsciidocContent(content []byte) []byte {
        jww.INFO.Println("Rendering with", path, "...")
        cmd := exec.Command(path, "--no-header-footer", "--safe", "-")
        cmd.Stdin = bytes.NewReader(cleanContent)
-       var out bytes.Buffer
+       var out, cmderr bytes.Buffer
        cmd.Stdout = &out
-       if err := cmd.Run(); err != nil {
+       cmd.Stderr = &cmderr
+       err := cmd.Run()
+       // asciidoctor has exit code 0 even if there are errors in stderr
+       // -> log stderr output regardless of state of err
+       for _, item := range strings.Split(string(cmderr.Bytes()), "\n") {
+               item := strings.TrimSpace(item)
+               if item != "" {
+                       jww.ERROR.Println(item)
+               }
+       }
+       if err != nil {
                jww.ERROR.Println(err)
        }