use master branch as refname if no refname actually available

Author: tayloraswift

Sources/SwiftinitPages/Contexts/IdentifiablePageContext.swift

@@ -18,6 +18,7 @@ class IdentifiablePageContext<Vertices> where Vertices:Swiftinit.VertexCache
     private
     var cache:Cache
 
+    @usableFromInline
     let repo:Unidoc.PackageRepo?
 
     init(cache:Cache, repo:Unidoc.PackageRepo?)
@@ -141,9 +142,6 @@ extension IdentifiablePageContext:Swiftinit.VertexPageContext
     @usableFromInline
     var volume:Unidoc.VolumeMetadata { self.cache.volumes.principal }
 
-    @usableFromInline
-    var origin:Unidoc.PackageOrigin? { self.repo?.origin }
-
     @usableFromInline
     subscript(secondary volume:Unidoc.Edition) -> Unidoc.VolumeMetadata?
     {

Sources/SwiftinitPages/Contexts/Swiftinit.VertexPageContext (ext).swift

@@ -54,7 +54,7 @@ extension Swiftinit.VertexPageContext
         guard
         let refname:String = self[file.edition]?.refname,
         let vertex:Unidoc.FileVertex = self[file: file],
-        let origin:Unidoc.PackageOrigin = self.origin
+        let origin:Unidoc.PackageOrigin = self.repo?.origin
         else
         {
             return nil
@@ -79,14 +79,15 @@ extension Swiftinit.VertexPageContext
     func link(media file:Unidoc.FileVertex) -> String?
     {
         guard
-        let refname:String = self[file.id.edition]?.refname,
-        let origin:Unidoc.PackageOrigin = self.origin
+        let repo:Unidoc.PackageRepo = self.repo
         else
         {
             return nil
         }
 
-        switch origin
+        let refname:String = self[file.id.edition]?.refname ?? repo.master
+
+        switch repo.origin
         {
         case .github(let origin):
             return """

Sources/SwiftinitRender/Swiftinit.VertexPageContext.swift

@@ -17,7 +17,7 @@ protocol _SwiftinitVertexPageContext:AnyObject
 {
     /// Returns the metadata document for the principal volume of the associated page.
     var volume:Unidoc.VolumeMetadata { get }
-    var origin:Unidoc.PackageOrigin? { get }
+    var repo:Unidoc.PackageRepo? { get }
 
     /// Returns the metadata document for the specified volume, if available.
     subscript(volume:Unidoc.Edition) -> Unidoc.VolumeMetadata? { get }