When a release doc only exists as a template, copy it into the right path

Signed-off-by: Pedro Algarvio <palgarvio@vmware.com>

doc/conf.py

@@ -420,6 +420,35 @@ class ReleasesTree(TocTree):
         return rst
 
 
+def copy_release_templates_pre(app):
+    app._copied_release_files = []
+    docs_path = pathlib.Path(docs_basepath)
+    release_files_dir = docs_path / "topics" / "releases"
+    release_template_files_dir = release_files_dir / "templates"
+    for fpath in release_template_files_dir.iterdir():
+        dest = release_files_dir / fpath.name.replace(".template", "")
+        if dest.exists():
+            continue
+        log.info(
+            "Copying '%s' -> '%s' just for this build ...",
+            fpath.relative_to(docs_path),
+            dest.relative_to(docs_path),
+        )
+        app._copied_release_files.append(dest)
+        shutil.copyfile(fpath, dest)
+
+
+def copy_release_templates_post(app, exception):
+    docs_path = pathlib.Path(docs_basepath)
+    for fpath in app._copied_release_files:
+        log.info(
+            "The release file '%s' was copied for the build, but its not in "
+            "version control system. Deleting.",
+            fpath.relative_to(docs_path),
+        )
+        fpath.unlink()
+
+
 def extract_module_deprecations(app, what, name, obj, options, lines):
     """
     Add a warning to the modules being deprecated into extensions.
@@ -452,4 +481,6 @@ def extract_module_deprecations(app, what, name, obj, options, lines):
 def setup(app):
     app.add_directive("releasestree", ReleasesTree)
     app.connect("autodoc-skip-member", skip_mod_init_member)
+    app.connect("builder-inited", copy_release_templates_pre)
+    app.connect("build-finished", copy_release_templates_post)
     app.connect("autodoc-process-docstring", extract_module_deprecations)