Fix changelog generation for non-default versions

Currently if you generate a changelog for r0.1.1 of an API, you'd get "No significant changes" which is wrong. You should get a real changelog for the version.

This is now handled by generating a "preferred" changelog which acts as the default for version variables in the RST. Using a specific version's changelog is still supported for the rare cases where that is desired.

scripts/templating/matrix_templates/sections.py

@@ -41,7 +41,7 @@ class MatrixSections(Sections):
                 version_var = "%s_%s" % (spec_var, version)
                 logger.info("Rendering changelog for %s" % version_var)
                 rendered[version_var] = changelog
-                if version == "unstable":
+                if version == "preferred":
                     rendered[spec_var] = changelog
         return rendered
 

scripts/templating/matrix_templates/units.py

@@ -903,9 +903,17 @@ class MatrixUnits(Units):
 
         return schema
 
-    def load_changelogs(self):
+    def load_changelogs(self, substitutions):
         changelogs = {}
 
+        preferred_versions = {
+            "server_server": substitutions.get("%SERVER_RELEASE_LABEL%", "unstable"),
+            "client_server": substitutions.get("%CLIENT_RELEASE_LABEL%", "unstable"),
+            "identity_service": substitutions.get("%IDENTITY_RELEASE_LABEL%", "unstable"),
+            "push_gateway": substitutions.get("%PUSH_GATEWAY_RELEASE_LABEL%", "unstable"),
+            "application_service": substitutions.get("%APPSERVICE_RELEASE_LABEL%", "unstable"),
+        }
+
         # Changelog generation is a bit complicated. We rely on towncrier to
         # generate the unstable/current changelog, but otherwise use the RST
         # edition to record historical changelogs. This is done by prepending
@@ -1007,6 +1015,10 @@ class MatrixUnits(Units):
                     title_part = keyword_versions[title_part]
                 changelog = "".join(changelog_lines)
                 changelogs[name][title_part.replace("^[a-zA-Z0-9]", "_").lower()] = changelog
+            preferred_changelog = changelogs[name]["unstable"]
+            if name in preferred_versions:
+                preferred_changelog = changelogs[name][preferred_versions[name]]
+            changelogs[name]["preferred"] = preferred_changelog
 
         return changelogs