doc: fix garbage text in generated HTML guides

If the user has MAKEFLAGS set in the environment when building the
documentation, the doc/guides/conf.py script which calls "make"
exclusively to get the project version might pick up garbage from
stdout, like:

<title>FAQ &mdash; Data Plane Development Kit make[2]:
Entering directory &#39;/build/1st/dpdk-18.11/doc/guides&#39;
18.11.0
make[2]: Leaving directory &#39;/build/1st/dpdk-18.11&#39;
documentation</title>

Override MAKEFLAGS in the Python subprocess call to avoid this issue.

Fixes: f7aaae2fe6f7 ("doc: add copyright and version")
Cc: stable@dpdk.org
Signed-off-by: Luca Boccassi <bluca@debian.org>

diff --git a/doc/guides/conf.py b/doc/guides/conf.py
index c883306..da99a3f 100644 (file)
--- a/doc/guides/conf.py
+++ b/doc/guides/conf.py
@@ -9,6 +9,7 @@ from sphinx import __version__ as sphinx_version
 from sphinx.highlighting import PygmentsBridge
 from pygments.formatters.latex import LatexFormatter
 from os import listdir
+from os import environ
 from os.path import basename
 from os.path import dirname
 from os.path import join as path_join
@@ -37,7 +38,9 @@ html_add_permalinks = ""
 html_show_copyright = False
 highlight_language = 'none'
 
-version = subprocess.check_output(['make', '-sRrC', '../../', 'showversion'])
+# If MAKEFLAGS is exported by the user, garbage text might end up in version
+version = subprocess.check_output(['make', '-sRrC', '../../', 'showversion'],
+                                  env=dict(environ, MAKEFLAGS=""))
 version = version.decode('utf-8').rstrip()
 release = version