fix: Fix common settings loading when root is synthetic

**Problem**
The new common settings feature doesn't work when the root isn't created by the user.

**Solution**
This fixes common settings by calling `expandCommonSettingsPerBase(...)` on
the synthetic root's base first.

main/src/main/scala/sbt/internal/Load.scala

@@ -28,7 +28,7 @@ import sbt.librarymanagement.ivy.{ InlineIvyConfiguration, IvyDependencyResoluti
 import sbt.librarymanagement.{ Configuration, Configurations, Resolver }
 import sbt.nio.Settings
 import sbt.util.{ Logger, Show }
-import xsbti.{ HashedVirtualFileRef, VirtualFile }
+import xsbti.{ FileConverter, HashedVirtualFileRef, VirtualFile }
 import xsbti.compile.{ ClasspathOptionsUtil, Compilers }
 import java.io.File
 import java.net.URI
@@ -943,13 +943,13 @@ private[sbt] object Load {
       extraSbtFiles: Seq[VirtualFile],
       converter: MappedFileConverter,
   ): LoadedProjects =
-    /*timed(s"Load.loadTransitive(${ newProjects.map(_.id) })", log)*/ {
+    // alias for parameter forwarding
-      def load(
+    def loadTransitive1(
         newProjects: Seq[Project],
         acc: Seq[Project],
         generated: Seq[Path],
         commonSettings0: Seq[Setting[_]],
-      ) =
+    ): LoadedProjects =
       loadTransitive(
         newProjects,
         buildBase,
@@ -968,6 +968,16 @@ private[sbt] object Load {
         converter,
       )
 
+    // alias for parameter forwarding
+    def expandCommonSettingsPerBase1(directory: File): Seq[Setting[?]] =
+      expandCommonSettingsPerBase(
+        directory = directory,
+        memoSettings = memoSettings,
+        extraSbtFiles = extraSbtFiles,
+        converter = converter,
+        log = log,
+      )
+
     // load all relevant configuration files (.sbt, as .scala already exists at this point)
     def discover(base: File): DiscoveredProjects = {
       val auto =
@@ -997,16 +1007,17 @@ private[sbt] object Load {
         try plugins.detected.deducePluginsFromProject(p1, log)
         catch { case e: AutoPluginException => throw translateAutoPluginException(e, p) }
       val p2 =
-          resolveProject(
+        resolveProjectSettings(
-            p1,
+          p = p1,
-            autoPlugins,
+          projectPlugins = autoPlugins,
-            plugins,
+          loadedPlugins = plugins,
-            commonSettings,
+          commonSettings =
-            machineWideUserSettings,
+            commonSettings ++ expandCommonSettingsPerBase1(p1.base.getCanonicalFile()),
-            memoSettings,
+          machineWideUserSettings = machineWideUserSettings,
-            extraFiles,
+          memoSettings = memoSettings,
-            converter,
+          extraSbtFiles = extraFiles,
-            log
+          converter = converter,
+          log = log,
         )
       val projectLevelExtra =
         if (expand) {
@@ -1031,7 +1042,7 @@ private[sbt] object Load {
       val newProjects = rest ++ discovered ++ projectLevelExtra
       val newAcc = acc :+ finalRoot
       val newGenerated = generated ++ generatedConfigClassFiles
-        load(newProjects, newAcc, newGenerated, finalRoot.commonSettings)
+      loadTransitive1(newProjects, newAcc, newGenerated, finalRoot.commonSettings)
     }
 
     // Load all config files AND finalize the project at the root directory, if it exists.
@@ -1054,16 +1065,23 @@ private[sbt] object Load {
             case None =>
               log.debug(s"[Loading] Found non-root projects $discoveredIdsStr")
               // Here we do something interesting... We need to create an aggregate root project
-                val otherProjects = load(discovered, acc, Nil, Nil)
               val root = {
-                  val existingIds = otherProjects.projects.map(_.id)
+                val defaultID = autoID(buildBase, context, Nil)
-                  val defaultID = autoID(buildBase, context, existingIds)
+                if discovered.isEmpty || java.lang.Boolean.getBoolean("sbt.root.ivyplugin") then
-                  val refs = existingIds.map(id => ProjectRef(buildUri, id))
+                  BuildDef.defaultProject(defaultID, buildBase)
-                  if (discovered.isEmpty || java.lang.Boolean.getBoolean("sbt.root.ivyplugin"))
+                else BuildDef.generatedRootSkipPublish(defaultID, buildBase, Nil)
-                    BuildDef.defaultAggregatedProject(defaultID, buildBase, refs)
-                  else BuildDef.generatedRootSkipPublish(defaultID, buildBase, refs)
               }
-                (root, false, Nil, otherProjects)
+              val otherProjects =
+                loadTransitive1(
+                  newProjects = discovered,
+                  acc = acc,
+                  generated = Nil,
+                  commonSettings0 = commonSettings
+                    ++ expandCommonSettingsPerBase1(buildBase.getCanonicalFile()),
+                )
+              val existingIds = otherProjects.projects.map(_.id)
+              val refs = existingIds.map(id => ProjectRef(buildUri, id))
+              (root.aggregate(refs: _*), false, Nil, otherProjects)
         val (finalRoot, projectLevelExtra) =
           timed(s"Load.loadTransitive: finalizeProject($root)", log) {
             finalizeProject(root, files, extraFiles, expand)
@@ -1072,12 +1090,12 @@ private[sbt] object Load {
         val newAcc = finalRoot +: (acc ++ otherProjects.projects)
         val newGenerated =
           generated ++ otherProjects.generatedConfigClassFiles ++ generatedConfigClassFiles
-          load(newProjects, newAcc, newGenerated, finalRoot.commonSettings)
+        loadTransitive1(newProjects, newAcc, newGenerated, finalRoot.commonSettings)
       case Nil =>
         val projectIds = acc.map(_.id).mkString("(", ", ", ")")
         log.debug(s"[Loading] Done in $buildBase, returning: $projectIds")
         LoadedProjects(acc, generatedConfigClassFiles)
-    }
+  end loadTransitive
 
   private[this] def translateAutoPluginException(
       e: AutoPluginException,
@@ -1116,18 +1134,18 @@ private[sbt] object Load {
    * @param extraSbtFiles Extra *.sbt files.
    * @param log  A logger to report auto-plugin issues to.
    */
-  private[sbt] def resolveProject(
+  private[sbt] def resolveProjectSettings(
       p: Project,
       projectPlugins: Seq[AutoPlugin],
       loadedPlugins: LoadedPlugins,
-      commonSettings0: Seq[Setting[_]],
+      commonSettings: Seq[Setting[_]],
       machineWideUserSettings: InjectSettings,
       memoSettings: mutable.Map[VirtualFile, LoadedSbtFile],
       extraSbtFiles: Seq[VirtualFile],
       converter: MappedFileConverter,
       log: Logger
   ): Project =
-    timed(s"Load.resolveProject(${p.id})", log) {
+    timed(s"Load.resolveProjectSettings(${p.id})", log) {
       import AddSettings._
       val autoConfigs = projectPlugins.flatMap(_.projectConfigurations)
       val auto = AddSettings.allDefaults
@@ -1150,35 +1168,7 @@ private[sbt] object Load {
             case _ => Nil
         expandPluginSettings(auto)
       }
-      def buildWideCommonSettings: Seq[Setting[_]] = {
+      def allProjectSettings: Seq[Setting[_]] =
-        // TODO - This mechanism of applying settings could be off... It's in two places now...
-        lazy val defaultSbtFiles = configurationSources(p.base.getCanonicalFile())
-          .map(_.getAbsoluteFile().toPath())
-          .map(converter.toVirtualFile)
-        lazy val sbtFiles: Seq[VirtualFile] = defaultSbtFiles ++ extraSbtFiles
-        // Grab all the settings we already loaded from sbt files
-        def settings(files: Seq[VirtualFile]): Seq[Setting[_]] =
-          if files.nonEmpty then
-            log.info(
-              s"${files.map(_.name()).mkString(s"loading settings for project ${p.id} from ", ",", " ...")}"
-            )
-          else ()
-          for
-            file <- files
-            config <- memoSettings.get(file).toSeq
-            setting <- config.settings
-          yield setting
-        def expandCommonSettings(auto: AddSettings): Seq[Setting[_]] =
-          auto match
-            case sf: DefaultSbtFiles => settings(sbtFiles.filter(sf.include))
-            case q: Sequence =>
-              q.sequence.foldLeft(Seq.empty[Setting[_]]) { (b, add) =>
-                b ++ expandCommonSettings(add)
-              }
-            case _ => Nil
-        commonSettings0 ++ expandCommonSettings(auto)
-      }
-      def allProjectSettings: Seq[Setting[_]] = {
         // Expand the AddSettings instance into a real Seq[Setting[_]] we'll use on the project
         def expandSettings(auto: AddSettings): Seq[Setting[_]] =
           auto match
@@ -1190,14 +1180,46 @@ private[sbt] object Load {
               }
             case _ => Nil
         expandSettings(auto)
-      }
+      end allProjectSettings
+
       // Finally, a project we can use in buildStructure.
-      p.copy(settings = allAutoPluginSettings ++ buildWideCommonSettings ++ allProjectSettings)
+      p.copy(settings = allAutoPluginSettings ++ commonSettings ++ allProjectSettings)
-        .setCommonSettings(buildWideCommonSettings)
+        .setCommonSettings(commonSettings)
         .setAutoPlugins(projectPlugins)
         .prefixConfigs(autoConfigs: _*)
     }
 
+  private[this] def expandCommonSettingsPerBase(
+      directory: File,
+      memoSettings: mutable.Map[VirtualFile, LoadedSbtFile],
+      extraSbtFiles: Seq[VirtualFile],
+      converter: MappedFileConverter,
+      log: Logger
+  ): Seq[Setting[_]] =
+    val defaultSbtFiles = configurationSources(directory)
+      .map(_.getAbsoluteFile().toPath())
+      .map(converter.toVirtualFile)
+      .toVector
+    val sbtFiles = defaultSbtFiles ++ extraSbtFiles.toVector
+    // Grab all the settings we already loaded from sbt files
+    def settings(files: Vector[VirtualFile]): Vector[Setting[_]] =
+      for
+        file <- files
+        config <- memoSettings.get(file).toSeq
+        setting <- config.settings
+      yield setting
+    import AddSettings.*
+    def expandCommonSettings(auto: AddSettings): Vector[Setting[_]] =
+      auto match
+        case sf: DefaultSbtFiles => settings(sbtFiles.filter(sf.include))
+        case q: Sequence =>
+          q.sequence.foldLeft(Vector.empty[Setting[_]]) { (b, add) =>
+            b ++ expandCommonSettings(add)
+          }
+        case _ => Vector.empty
+    expandCommonSettings(AddSettings.allDefaults).distinct
+  end expandCommonSettingsPerBase
+
   /**
    * This method attempts to discover all Project/settings it can using the configured AddSettings and project base.
    *

sbt-app/src/sbt-test/actions/cross-strict-aggregation-scala-3/build.sbt

@@ -1,5 +1,4 @@
 scalaVersion := "2.12.19"
-name := "root"
 
 lazy val core = project
   .settings(

sbt-app/src/sbt-test/dependency-management/parent-skip-publish/build.sbt

@@ -1,11 +1,9 @@
-ThisBuild / organization := "com.example"
+organization := "com.example"
-ThisBuild / ivyPaths := IvyPaths((ThisBuild / baseDirectory).value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
+ivyPaths := IvyPaths((ThisBuild / baseDirectory).value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
 
 name := "root"
 
 lazy val core = project
   .settings(
     name := "core",
-    // organization := "com.example",
-    ivyPaths := IvyPaths((ThisBuild / baseDirectory).value.toString, Some(((ThisBuild / baseDirectory).value / "ivy" / "cache").toString))
   )

sbt-app/src/sbt-test/project-matrix/custom/build.sbt

@@ -1,12 +1,11 @@
-ThisBuild / organization := "com.example"
+organization := "com.example"
-ThisBuild / version := "0.1.0-SNAPSHOT"
+version := "0.1.0-SNAPSHOT"
-ThisBuild / publishMavenStyle := true
+publishMavenStyle := true
-
+ivyPaths := {
-ThisBuild / ivyPaths := {
+  val base = baseDirectory.value
-  val base = (ThisBuild / baseDirectory).value
+  val thisBuildBase = (ThisBuild / baseDirectory).value
-  IvyPaths(base.toString, s"$base/ivy-cache")
+  IvyPaths(base.toString, s"$thisBuildBase/ivy-cache")
 }
-publish / skip := true
 
 lazy val config12 = ConfigAxis("Config1_2", "config1.2")
 lazy val config13 = ConfigAxis("Config1_3", "config1.3")
@@ -21,7 +20,6 @@ lazy val app = (projectMatrix in file("app"))
   .dependsOn(core)
   .settings(
     name := "app",
-    ivyPaths := (ThisBuild / ivyPaths).value
   )
   .customRow(
     scalaVersions = Seq(scala212, scala211),

sbt-app/src/sbt-test/project-matrix/java/build.sbt

@@ -1,12 +1,11 @@
-ThisBuild / organization := "com.example"
+organization := "com.example"
-ThisBuild / version := "0.1.0-SNAPSHOT"
+version := "0.1.0-SNAPSHOT"
-ThisBuild / publishMavenStyle := true
+publishMavenStyle := true
-
+ivyPaths := {
-ThisBuild / ivyPaths := {
+  val base = baseDirectory.value
-  val base = (ThisBuild / baseDirectory).value
+  val thisBuildBase = (ThisBuild / baseDirectory).value
-  IvyPaths(base.toString, s"$base/ivy-cache")
+  IvyPaths(base.toString, s"$thisBuildBase/ivy-cache")
 }
-publish / skip := true
 
 lazy val config12 = ConfigAxis("Config1_2", "-config1.2")
 lazy val config13 = ConfigAxis("Config1_3", "-config1.3")
@@ -16,7 +15,6 @@ lazy val scala212 = "2.12.10"
 lazy val app = (projectMatrix in file("app"))
   .settings(
     name := "app",
-    ivyPaths := (ThisBuild / ivyPaths).value
   )
   .customRow(
     scalaVersions = Seq(scala212),

sbt-app/src/sbt-test/project/bare-settings/build.sbt

@@ -1,13 +0,0 @@
-lazy val check = taskKey[Unit]("")
-lazy val root = (project in file("."))
-lazy val foo = project
-lazy val bar = project
-
-def scala212 = "2.12.17"
-scalaVersion := scala212
-
-check := {
-  assert((root / scalaVersion).value == scala212)
-  assert((foo / scalaVersion).value == scala212)
-  assert((bar / scalaVersion).value == scala212)
-}

sbt-app/src/sbt-test/project/common-settings-synthetic-root/baz/build.sbt

@@ -0,0 +1 @@
+organization := "com.example.baz"

sbt-app/src/sbt-test/project/common-settings-synthetic-root/build.sbt

@@ -0,0 +1,28 @@
+lazy val check = taskKey[Unit]("")
+
+def scala212 = "2.12.19"
+scalaVersion := scala212
+val o = "com.example"
+organization := o
+
+lazy val foo = project
+lazy val bar = project
+  .settings(
+    name := "bar",
+    organization := "com.example.bar",
+  )
+
+lazy val baz = project
+
+check := {
+  assert((foo / scalaVersion).value == scala212)
+  assert((bar / scalaVersion).value == scala212)
+  assert((baz / scalaVersion).value == scala212)
+
+  assert((foo / organization).value == o)
+  // Test that bar can override common setting in settings(...)
+  assert((bar / organization).value == "com.example.bar", s"unexpected bar / organization = {(bar / organization).value}")
+  // Test that baz/build.sbt bare settings get loaded
+  assert((baz / organization).value == "com.example.baz", s"unexpected baz/organization")
+}
+check / aggregate := false

sbt-app/src/sbt-test/project/common-settings-synthetic-root/test

@@ -0,0 +1 @@
+> check

sbt-app/src/sbt-test/project/common-settings/baz/build.sbt

@@ -0,0 +1 @@
+organization := "com.example.baz"

sbt-app/src/sbt-test/project/common-settings/build.sbt

@@ -0,0 +1,33 @@
+lazy val check = taskKey[Unit]("")
+
+def scala212 = "2.12.19"
+scalaVersion := scala212
+val o = "com.example"
+organization := o
+
+lazy val root = (project in file("."))
+  .aggregate(foo, bar, baz)
+
+lazy val foo = project
+lazy val bar = project
+  .settings(
+    name := "bar",
+    organization := "com.example.bar",
+  )
+
+lazy val baz = project
+
+check := {
+  assert((root / scalaVersion).value == scala212)
+  assert((foo / scalaVersion).value == scala212)
+  assert((bar / scalaVersion).value == scala212)
+  assert((baz / scalaVersion).value == scala212)
+
+  assert((root / organization).value == o)
+  assert((foo / organization).value == o)
+  // Test that bar can override common setting in settings(...)
+  assert((bar / organization).value == "com.example.bar")
+  // Test that baz/build.sbt bare settings get loaded
+  assert((baz / organization).value == "com.example.baz")
+}
+check / aggregate := false

sbt-app/src/sbt-test/project/common-settings/test

@@ -0,0 +1 @@
+> check

sbt-app/src/sbt-test/reporter/nowarn/build.sbt

@@ -1,13 +1,19 @@
-ThisBuild / scalaVersion := "2.12.17"
+scalaVersion := "2.12.19"
 
 lazy val sub1 = project
 
 lazy val sub2 = project
 
 val assertNoWarning = taskKey[Unit]("checks warning *is not* emitted")
-
 val assertWarning = taskKey[Unit]("checks warning *is* emitted")
 
+lazy val root = (project in file("."))
+  .aggregate(sub1, sub2)
+  .settings(
+    assertWarning := check(true).value,
+    assertNoWarning := check(false).value,
+  )
+
 def check(expectation: Boolean) = Def.task[Unit] {
   val lastLog: File = BuiltinCommands.lastLogFile(state.value).get
   val last: String = IO.read(lastLog)
@@ -20,7 +26,3 @@ def check(expectation: Boolean) = Def.task[Unit] {
     IO.write(lastLog, "") // clear the backing log for for 'last'.
   }
 }
-
-assertWarning := check(true).value
-
-assertNoWarning := check(false).value