meson: adjust whitespace handling in jinja2 rendering

In 6abe882bae1bb12827ef395c60f21ab8bb1bc61b the renderer was made to
unconditionally append a newline to output. This works, but is ugly. A nicer
solution is to tell jinja2 to not strip the newline in the first place, via
keep_trailing_newline=True. It seems that the result is unchanged because all
our source files have exactly one trailing newline.

Also, enable lstrip_blocks=True. This would cause whitespace on the line before
an {%if block to be automatically stripped. It seems reasonable to enable that
if trim_blocks=True.

Overall, no change is expected, though I didn't test combinations of
configurations, so there might be a change in some cases. But now the rules of
rendering are more logical, e.g. we should be able to indent nested conditional
statements without getting unexpected whitespace in the output.

1 files changed, 5 insertions, 2 deletions

diff --git a/tools/meson-render-jinja2.py b/tools/meson-render-jinja2.py
index fbaae596de..6ccb1fbe0c 100755
--- a/tools/meson-render-jinja2.py
+++ b/tools/meson-render-jinja2.py
@@ -23,7 +23,11 @@ def parse_config_h(filename):
 
 def render(filename, defines):
     text = open(filename).read()
-    template = jinja2.Template(text, trim_blocks=True, undefined=jinja2.StrictUndefined)
+    template = jinja2.Template(text,
+                               trim_blocks=True,
+                               lstrip_blocks=True,
+                               keep_trailing_newline=True,
+                               undefined=jinja2.StrictUndefined)
     return template.render(defines)
 
 if __name__ == '__main__':
@@ -32,6 +36,5 @@ if __name__ == '__main__':
     output = render(sys.argv[3], defines)
     with open(sys.argv[4], 'w') as f:
         f.write(output)
-        f.write('\n')
     info = os.stat(sys.argv[3])
     os.chmod(sys.argv[4], info.st_mode)