doc: make sphinx errors more visible

When running Sphinx through ninja, the wrapper configured in meson
redirects stdout to a log file.
It makes more important to print issues on stderr.

Some warnings generated by the conf.py were hidden because
printed on stdout. The first improvement is to print them on stderr.

The second measure is to stop processing if meson was configured
with --werror.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

diff --git a/doc/guides/conf.py b/doc/guides/conf.py
index 2ffe5a5..9de490e 100644 (file)
--- a/doc/guides/conf.py
+++ b/doc/guides/conf.py
@@ -12,6 +12,7 @@ from os import environ
 from os.path import basename
 from os.path import dirname
 from os.path import join as path_join
+from sys import argv, stderr
 
 import configparser
 
@@ -22,9 +23,12 @@ try:
     html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
 except:
     print('Install the sphinx ReadTheDocs theme for improved html documentation '
-          'layout: https://sphinx-rtd-theme.readthedocs.io/')
+          'layout: https://sphinx-rtd-theme.readthedocs.io/',
+          file=stderr)
     pass
 
+stop_on_error = ('-W' in argv)
+
 project = 'Data Plane Development Kit'
 html_logo = '../logo/DPDK_logo_vertical_rev_small.png'
 latex_logo = '../logo/DPDK_logo_horizontal_tag.png'
@@ -217,7 +221,10 @@ def generate_overview_table(output_filename, table_id, section, table_name, titl
         if not config.has_section(section):
             print("{}: File '{}' has no [{}] secton".format(warning,
                                                             ini_filename,
-                                                            section))
+                                                            section),
+                                                            file=stderr)
+            if stop_on_error:
+                raise Exception('Warning is treated as a failure')
             continue
 
         # Check for valid features names.
@@ -225,7 +232,10 @@ def generate_overview_table(output_filename, table_id, section, table_name, titl
             if name not in valid_features:
                 print("{}: Unknown feature '{}' in '{}'".format(warning,
                                                                 name,
-                                                                ini_filename))
+                                                                ini_filename),
+                                                                file=stderr)
+                if stop_on_error:
+                    raise Exception('Warning is treated as a failure')
                 continue
 
             if value:
@@ -418,7 +428,8 @@ def setup(app):
 
     if LooseVersion(sphinx_version) < LooseVersion('1.3.1'):
         print('Upgrade sphinx to version >= 1.3.1 for '
-              'improved Figure/Table number handling.')
+              'improved Figure/Table number handling.',
+              file=stderr)
         # Add a role to handle :numref: references.
         app.add_role('numref', numref_role)
         # Process the numref references once the doctree has been created.