Add PublishCredentialsModule, MavenPublish and MavenPublishModule (#6023)

### Summary

Implements #5592 and builds upon #5601.

### High Level Overview of Changes

This PR implements three traits:

- `MavenPublishModule` is meant to mirror `SonatypeCentralPublishModule`
for plain (!?) Maven repositories
- `MavenModule` contains the actual publishing logic. This has been
taken from parts of `SonatypeCentralPublishModule` and is now extended
by both `MavenPublishModule` as well ass `SonatypeCentralPublishModule`
to share code
- `MavenCredentialsModule` contains tasks for obtaining Maven/Sonatype
credentials. These tasks have been extracted from the
`SonatypeCentralPublishModule` to be shared by both it and the new
`MavenPublishModule`

### Differences between this PR and #5601 

#### Code Structure

#5601 essentially copied parts of `SonatypeCentralPublishModule` to
create `MavenPublishModule`. Apart from duplicating code, this also
created code you may find confusing in places (e.g. by containing a
function named
[publishSnapshot](https://github.com/com-lihaoyi/mill/pull/5601/files#diff-7ffbad225d6fa5d1de00e7ea2066f029c9fe4b90c09785ac3cd51ea0d12b3638R126)
which is used to publish both release and snapshot artifacts). This PR
tries to improve upon that by instead factoring out all code which can
be factored out.

#### Removal of Unused Settings

#5601 defines the tasks `mavenConnectTimeout`, `mavenReadTimeout` and
`mavenAwaitTimeout` as part of the `MavenPublishModule`. These are
however not actually used anywhere. They are used in
`SonatypeCentralPublishModule` and are specific to publishing releases
to Sonatype Central.

#### Bugfix for Choosing the Repo URI

The below was changed after being identified during testing with a
private build.

```diff
- val uri = if (isSnapshot) releaseUri else snapshotUri
+ val uri = if (isSnapshot) snapshotUri else releaseUri
```

### Open Question: Build Compilation Error When Extending
`MavenPublishModule`

When running `./mill dist.installLocalCache` and then using the local
`SNAPSHOT` version of mill including the changes made in this PR in a
build and extending `MavenPublishModule` in a local build module, I
currently get the following exception when running `./mill resolve _` on
that build:

```
[build.mill-59] [error] ## Exception when compiling 23 sources to /home/max/Repositories/github.com/ttmzero/rtp-backend/out/mill-build/compile.dest/classes
[build.mill-59] [error] dotty.tools.dotc.core.MissingType: Cannot resolve reference to type com.lumidion.sonatype.central.client.core.type.SonatypeCredentials.
[build.mill-59] [error] The classfile defining the type might be missing from the classpath.
```

This error can be removed by defining `Deps.sonatypeCentralClient` as a
`mvnDeps` instead of both a `compileMvnDeps` and a `runMvnDeps` in
`libs/scalalib/package.mill` and `libs/javalib/package.mill`. I do not
know why this is the case and would require some help here.

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: maxstreese

libs/javalib/src/mill/javalib/MavenPublish.scala

@@ -0,0 +1,85 @@
+package mill.javalib
+
+import com.lumidion.sonatype.central.client.core.SonatypeCredentials
+import mill.api.daemon.Logger
+import mill.javalib.PublishModule.PublishData
+import mill.javalib.internal.MavenWorkerSupport as InternalMavenWorkerSupport
+
+private[mill] trait MavenPublish {
+
+  def mavenPublishDatas(
+      publishDatas: Seq[PublishData],
+      credentials: SonatypeCredentials,
+      releaseUri: String,
+      snapshotUri: String,
+      taskDest: os.Path,
+      log: Logger,
+      env: Map[String, String],
+      worker: InternalMavenWorkerSupport.Api
+  ): Unit = {
+    val dryRun = env.get("MILL_TESTS_PUBLISH_DRY_RUN").contains("1")
+
+    val (snapshots, releases) = publishDatas.partition(_.meta.isSnapshot)
+
+    releases.map(_ -> false).appendedAll(snapshots.map(_ -> true)).foreach { (data, isSnapshot) =>
+      mavenPublishData(
+        dryRun = dryRun,
+        publishData = data,
+        isSnapshot = isSnapshot,
+        credentials = credentials,
+        releaseUri = releaseUri,
+        snapshotUri = snapshotUri,
+        taskDest = taskDest,
+        log = log,
+        worker = worker
+      )
+    }
+  }
+
+  def mavenPublishData(
+      dryRun: Boolean,
+      publishData: PublishData,
+      isSnapshot: Boolean,
+      credentials: SonatypeCredentials,
+      releaseUri: String,
+      snapshotUri: String,
+      taskDest: os.Path,
+      log: Logger,
+      worker: InternalMavenWorkerSupport.Api
+  ): Unit = {
+    val uri = if (isSnapshot) snapshotUri else releaseUri
+    val artifacts = MavenWorkerSupport.RemoteM2Publisher.asM2ArtifactsFromPublishDatas(
+      publishData.meta,
+      publishData.payloadAsMap
+    )
+
+    if (isSnapshot) {
+      log.info(
+        s"Detected a 'SNAPSHOT' version for ${publishData.meta}, publishing to Maven Repository at '$uri'"
+      )
+    }
+
+    /** Maven uses this as a workspace for file manipulation. */
+    val mavenWorkspace = taskDest / "maven"
+
+    if (dryRun) {
+      val publishTo = taskDest / "repository"
+      val result = worker.publishToLocal(
+        publishTo = publishTo,
+        workspace = mavenWorkspace,
+        artifacts
+      )
+      log.info(s"Dry-run publishing to '$publishTo' finished with result: $result")
+    } else {
+      val result = worker.publishToRemote(
+        uri = uri,
+        workspace = mavenWorkspace,
+        username = credentials.username,
+        password = credentials.password,
+        artifacts
+      )
+      log.info(s"Publishing to '$uri' finished with result: $result")
+    }
+  }
+
+}

libs/javalib/src/mill/javalib/MavenPublishModule.scala

@@ -0,0 +1,42 @@
+package mill.javalib
+
+import mill.*
+import mill.api.*
+import mill.util.Tasks
+
+/**
+ * External module to publish artifactes to Maven repositories other than `central.sonatype.org`
+ * (e.g. a private Maven repository).
+ */
+object MavenPublishModule extends ExternalModule, DefaultTaskModule, MavenWorkerSupport,
+      PublishCredentialsModule, MavenPublish {
+
+  def defaultTask(): String = "publishAll"
+
+  def publishAll(
+      publishArtifacts: mill.util.Tasks[PublishModule.PublishData] =
+        Tasks.resolveMainDefault("__:PublishModule.publishArtifacts"),
+      username: String = "",
+      password: String = "",
+      releaseUri: String,
+      snapshotUri: String
+  ): Command[Unit] = Task.Command {
+    val artifacts = Task.sequence(publishArtifacts.value)()
+
+    val credentials = getPublishCredentials("MILL_MAVEN", username, password)()
+
+    mavenPublishDatas(
+      artifacts,
+      credentials,
+      releaseUri = releaseUri,
+      snapshotUri = snapshotUri,
+      taskDest = Task.dest,
+      log = Task.log,
+      env = Task.env,
+      worker = mavenWorker()
+    )
+  }
+
+  lazy val millDiscover: Discover = Discover[this.type]
+
+}

libs/javalib/src/mill/javalib/PublishCredentialsModule.scala

@@ -0,0 +1,42 @@
+package mill.javalib
+
+import com.lumidion.sonatype.central.client.core.SonatypeCredentials
+import mill.api.*
+
+/**
+ * Internal module to Retrieve credentials for publishing to Maven repositories
+ * (e.g. `central.sonatype.org` or a private Maven repository).
+ */
+private[mill] trait PublishCredentialsModule extends Module {
+  def getPublishCredentials(
+      envVariablePrefix: String,
+      usernameParameterValue: String,
+      passwordParameterValue: String
+  ): Task[SonatypeCredentials] = Task.Anon {
+    val username =
+      getPublishCredential(usernameParameterValue, "username", s"${envVariablePrefix}_USERNAME")()
+    val password =
+      getPublishCredential(passwordParameterValue, "password", s"${envVariablePrefix}_PASSWORD")()
+    Result.Success(SonatypeCredentials(username, password))
+  }
+
+  private def getPublishCredential(
+      credentialParameterValue: String,
+      credentialName: String,
+      envVariableName: String
+  ): Task[String] = Task.Anon {
+    if (credentialParameterValue.nonEmpty) {
+      Result.Success(credentialParameterValue)
+    } else {
+      (for {
+        credential <- Task.env.get(envVariableName)
+      } yield {
+        Result.Success(credential)
+      }).getOrElse(
+        Result.Failure(
+          s"No $credentialName set. Consider using the $envVariableName environment variable or passing `$credentialName` argument"
+        )
+      )
+    }
+  }
+}

libs/javalib/src/mill/javalib/SonatypeCentralPublishModule.scala

@@ -1,29 +1,30 @@
 package mill.javalib
 
 import com.lihaoyi.unroll
-import com.lumidion.sonatype.central.client.core.{PublishingType, SonatypeCredentials}
+import com.lumidion.sonatype.central.client.core.PublishingType
+import com.lumidion.sonatype.central.client.core.SonatypeCredentials
 import mill.*
-import javalib.*
-import mill.api.{ExternalModule, Task}
-import mill.util.Tasks
+import mill.api.BuildCtx
 import mill.api.DefaultTaskModule
+import mill.api.ExternalModule
 import mill.api.Result
-import mill.javalib.SonatypeCentralPublishModule.{
-  defaultAwaitTimeout,
-  defaultConnectTimeout,
-  defaultCredentials,
-  defaultReadTimeout,
-  getPublishingTypeFromReleaseFlag,
-  getSonatypeCredentials
-}
-import mill.javalib.publish.Artifact
-import mill.javalib.publish.SonatypeHelpers.{PASSWORD_ENV_VARIABLE_NAME, USERNAME_ENV_VARIABLE_NAME}
-import mill.api.BuildCtx
+import mill.api.Task
 import mill.api.daemon.Logger
 import mill.javalib.PublishModule.PublishData
+import mill.javalib.SonatypeCentralPublishModule.defaultAwaitTimeout
+import mill.javalib.SonatypeCentralPublishModule.defaultConnectTimeout
+import mill.javalib.SonatypeCentralPublishModule.defaultCredentials
+import mill.javalib.SonatypeCentralPublishModule.defaultReadTimeout
+import mill.javalib.SonatypeCentralPublishModule.getPublishingTypeFromReleaseFlag
 import mill.javalib.internal.PublishModule.GpgArgs
+import mill.javalib.publish.Artifact
+import mill.javalib.publish.SonatypeHelpers.CREDENTIALS_ENV_VARIABLE_PREFIX
+import mill.util.Tasks
 
-trait SonatypeCentralPublishModule extends PublishModule, MavenWorkerSupport {
+import javalib.*
+
+trait SonatypeCentralPublishModule extends PublishModule, MavenWorkerSupport,
+      PublishCredentialsModule {
 
   @deprecated("Use `sonatypeCentralGpgArgsForKey` instead.", "Mill 1.0.1")
   def sonatypeCentralGpgArgs: T[String] =
@@ -63,7 +64,7 @@ trait SonatypeCentralPublishModule extends PublishModule, MavenWorkerSupport {
       @unroll docs: Boolean = true
   ): Task.Command[Unit] = Task.Command {
     val artifact = artifactMetadata()
-    val credentials = getSonatypeCredentials(username, password)()
+    val credentials = getPublishCredentials(CREDENTIALS_ENV_VARIABLE_PREFIX, username, password)()
     val publishData = publishArtifactsPayload(sources = sources, docs = docs)()
     val publishingType = getPublishingTypeFromReleaseFlag(sonatypeCentralShouldRelease())
 
@@ -97,8 +98,8 @@ trait SonatypeCentralPublishModule extends PublishModule, MavenWorkerSupport {
 /**
  * External module to publish artifacts to `central.sonatype.org`
  */
-object SonatypeCentralPublishModule extends ExternalModule with DefaultTaskModule
-    with MavenWorkerSupport {
+object SonatypeCentralPublishModule extends ExternalModule, DefaultTaskModule, MavenWorkerSupport,
+      PublishCredentialsModule, MavenPublish {
   private final val sonatypeCentralGpgArgsSentinelValue = "<user did not override this method>"
 
   def self = this
@@ -127,7 +128,7 @@ object SonatypeCentralPublishModule extends ExternalModule with DefaultTaskModul
     val artifacts = Task.sequence(publishArtifacts.value)()
 
     val finalBundleName = if (bundleName.isEmpty) None else Some(bundleName)
-    val credentials = getSonatypeCredentials(username, password)()
+    val credentials = getPublishCredentials(CREDENTIALS_ENV_VARIABLE_PREFIX, username, password)()
     def makeGpgArgs() = internal.PublishModule.pgpImportSecretIfProvidedAndMakeGpgArgs(
       Task.env,
       GpgArgs.fromUserProvided(gpgArgs)
@@ -169,37 +170,17 @@ object SonatypeCentralPublishModule extends ExternalModule with DefaultTaskModul
     val dryRun = env.get("MILL_TESTS_PUBLISH_DRY_RUN").contains("1")
 
     def publishSnapshot(publishData: PublishData): Unit = {
-      val uri = sonatypeCentralSnapshotUri
-      val artifacts = MavenWorkerSupport.RemoteM2Publisher.asM2ArtifactsFromPublishDatas(
-        publishData.meta,
-        publishData.payloadAsMap
-      )
-
-      log.info(
-        s"Detected a 'SNAPSHOT' version for ${publishData.meta}, publishing to Sonatype Central Snapshots at '$uri'"
+      mavenPublishData(
+        dryRun = dryRun,
+        publishData = publishData,
+        isSnapshot = true,
+        credentials = credentials,
+        releaseUri = sonatypeCentralSnapshotUri,
+        snapshotUri = sonatypeCentralSnapshotUri,
+        taskDest = taskDest,
+        log = log,
+        worker = worker
       )
-
-      /** Maven uses this as a workspace for file manipulation. */
-      val mavenWorkspace = taskDest / "maven"
-
-      if (dryRun) {
-        val publishTo = taskDest / "repository"
-        val result = worker.publishToLocal(
-          publishTo = publishTo,
-          workspace = mavenWorkspace,
-          artifacts
-        )
-        log.info(s"Dry-run publishing to '$publishTo' finished with result: $result")
-      } else {
-        val result = worker.publishToRemote(
-          uri = uri,
-          workspace = mavenWorkspace,
-          username = credentials.username,
-          password = credentials.password,
-          artifacts
-        )
-        log.info(s"Publishing to '$uri' finished with result: $result")
-      }
     }
 
     def publishReleases(artifacts: Seq[PublishData], gpgArgs: GpgArgs): Unit = {
@@ -258,36 +239,5 @@ object SonatypeCentralPublishModule extends ExternalModule with DefaultTaskModul
     }
   }
 
-  private def getSonatypeCredential(
-      credentialParameterValue: String,
-      credentialName: String,
-      envVariableName: String
-  ): Task[String] = Task.Anon {
-    if (credentialParameterValue.nonEmpty) {
-      Result.Success(credentialParameterValue)
-    } else {
-      (for {
-        credential <- Task.env.get(envVariableName)
-      } yield {
-        Result.Success(credential)
-      }).getOrElse(
-        Result.Failure(
-          s"No $credentialName set. Consider using the $envVariableName environment variable or passing `$credentialName` argument"
-        )
-      )
-    }
-  }
-
-  private def getSonatypeCredentials(
-      usernameParameterValue: String,
-      passwordParameterValue: String
-  ): Task[SonatypeCredentials] = Task.Anon {
-    val username =
-      getSonatypeCredential(usernameParameterValue, "username", USERNAME_ENV_VARIABLE_NAME)()
-    val password =
-      getSonatypeCredential(passwordParameterValue, "password", PASSWORD_ENV_VARIABLE_NAME)()
-    Result.Success(SonatypeCredentials(username, password))
-  }
-
   lazy val millDiscover: mill.api.Discover = mill.api.Discover[this.type]
 }

libs/javalib/src/mill/javalib/publish/SonatypeHelpers.scala

@@ -8,8 +8,9 @@ import java.security.MessageDigest
 object SonatypeHelpers {
   // http://central.sonatype.org/pages/working-with-pgp-signatures.html#signing-a-file
 
-  val USERNAME_ENV_VARIABLE_NAME = "MILL_SONATYPE_USERNAME"
-  val PASSWORD_ENV_VARIABLE_NAME = "MILL_SONATYPE_PASSWORD"
+  val CREDENTIALS_ENV_VARIABLE_PREFIX = "MILL_SONATYPE"
+  val USERNAME_ENV_VARIABLE_NAME = s"${CREDENTIALS_ENV_VARIABLE_PREFIX}_USERNAME"
+  val PASSWORD_ENV_VARIABLE_NAME = s"${CREDENTIALS_ENV_VARIABLE_PREFIX}_PASSWORD"
 
   private[mill] def getArtifactMappings(
       isSigned: Boolean,

libs/scalalib/src/mill/scalalib/aliases.scala

@@ -1,5 +1,7 @@
 package mill.scalalib
 
 object Dependency extends mill.api.ExternalModule.Alias(mill.javalib.Dependency)
+object MavenPublishModule
+    extends mill.api.ExternalModule.Alias(mill.javalib.MavenPublishModule)
 object SonatypeCentralPublishModule
     extends mill.api.ExternalModule.Alias(mill.javalib.SonatypeCentralPublishModule)