Merge pull request #292 from ennru/project-url-default

Default project.url to homepage

build.sbt

@@ -129,8 +129,7 @@ lazy val docs = (project in file("docs"))
     paradoxTheme := Some(builtinParadoxTheme("generic")),
     paradoxProperties in Compile ++= Map(
       "empty" -> "",
-      "version" -> version.value,
-      "project.url" -> "https://developer.lightbend.com/docs/paradox/current/",
+      "version" -> version.value
     ),
     paradoxGroups := Map("Language" -> Seq("Scala", "Java")),
     publish / skip := true

docs/src/main/paradox/configuration.md

@@ -57,7 +57,9 @@ Paradox supports showing a warning when users browse documentation which is not
 
 The built in theme (`generic`) contains Javascript to fetch the JSON file and compare the version with the version for which the documentation showing was generated. Whenever they differ, a warning text shows on every page offering a link to the released version's page.
 
-To use this functionality, add `project.url` to Paradox properties
+To use this functionality, make `project.url` point to a URL where the **current** version will be deployed. It defaults to the sbt `homepage` setting. Make sure `homepage` contains something useful.
+
+To set a URL different from `homepage`, add `project.url` to Paradox properties
 
 ```scala
 paradoxProperties += ("project.url" -> "https://developer.lightbend.com/docs/paradox/current/")
@@ -67,7 +69,7 @@ paradoxProperties += ("project.url" -> "https://developer.lightbend.com/docs/par
 
 The built-in theme (`generic`) will add a `<link rel="canonical" href=...` page header using the sbt `homepage` setting. Make sure `homepage` contains something useful.
 
-To set a different URL, add `canonical.base_url` to Paradox properties
+To set a URL different from `homepage`, add `canonical.base_url` to Paradox properties
 
 ```scala
 paradoxProperties += ("canonical.base_url" -> "https://developer.lightbend.com/docs/paradox/current/")

plugin/src/main/scala/com/lightbend/paradox/sbt/ParadoxPlugin.scala

@@ -95,8 +95,11 @@ object ParadoxPlugin extends AutoPlugin {
       "scala.binary.version" -> scalaBinaryVersion.value),
     paradoxProperties ++= {
       (homepage in ThisBuild).value match {
-        case Some(url) => Map("canonical.base_dir" -> url.toString)
-        case None      => Map.empty
+        case Some(url) => Map(
+          "project.url" -> url.toString,
+          "canonical.base_dir" -> url.toString
+        )
+        case None => Map.empty
       }
     },
     paradoxProperties ++= dateProperties,