Mark artifacts as optional if missingOk is true

modules/lm-coursier/src/main/scala/lmcoursier/CoursierDependencyResolution.scala

@@ -178,6 +178,7 @@ class CoursierDependencyResolution(conf: CoursierConfiguration) extends Dependen
         cache = cache0,
         parallel = conf.parallelDownloads,
         classpathOrder = conf.classpathOrder,
+        missingOk = conf.missingOk
       )
 
     val sbtBootJarOverrides = SbtBootJars(
@@ -208,6 +209,7 @@ class CoursierDependencyResolution(conf: CoursierConfiguration) extends Dependen
         includeSignatures = false,
         sbtBootJarOverrides = sbtBootJarOverrides,
         classpathOrder = conf.classpathOrder,
+        missingOk = conf.missingOk
       )
 
     val e = for {

modules/lm-coursier/src/main/scala/lmcoursier/internal/ArtifactsParams.scala

@@ -15,4 +15,5 @@ final case class ArtifactsParams(
   cache: FileCache[Task],
   parallel: Int,
   classpathOrder: Boolean,
+  missingOk: Boolean
 )

modules/lm-coursier/src/main/scala/lmcoursier/internal/ArtifactsRun.scala

@@ -51,6 +51,15 @@ object ArtifactsRun {
             else
               Nil
           }
+          .addTransformArtifacts { artifacts =>
+            if (params.missingOk)
+              artifacts.map {
+                case (dependency, publication, artifact) =>
+                  (dependency, publication, artifact.withOptional(true))
+              }
+            else
+              artifacts
+          }
           .withCache(
             params
               .cache

modules/lm-coursier/src/main/scala/lmcoursier/internal/ResolutionParams.scala

@@ -62,7 +62,7 @@ final case class ResolutionParams(
         cache = cleanCache
       ),
       cleanCache,
-      sbtClassifiers
+      missingOk
     )
   }
 

modules/lm-coursier/src/main/scala/lmcoursier/internal/SbtUpdateReport.scala

@@ -142,6 +142,7 @@ private[internal] object SbtUpdateReport {
     keepPomArtifact: Boolean = false,
     includeSignatures: Boolean = false,
     classpathOrder: Boolean,
+    missingOk: Boolean
   ): Vector[ModuleReport] = {
 
     val deps = classifiersOpt match {
@@ -156,8 +157,9 @@ private[internal] object SbtUpdateReport {
         deps.map {
           case (d, p, a) =>
             val d0 = d.withAttributes(d.attributes.withClassifier(p.classifier))
-            val f = map.get((d0, p, a)).flatten
-            (d, p, a, f) // not d0
+            val a0 = if (missingOk) a.withOptional(true) else a
+            val f = map.get((d0, p, a0)).flatten
+            (d, p, a0, f) // not d0
         }
       case None =>
         deps.map {
@@ -301,6 +303,7 @@ private[internal] object SbtUpdateReport {
     keepPomArtifact: Boolean = false,
     includeSignatures: Boolean = false,
     classpathOrder: Boolean,
+    missingOk: Boolean
   ): UpdateReport = {
 
     val configReports = configs.map {
@@ -324,6 +327,7 @@ private[internal] object SbtUpdateReport {
           keepPomArtifact = keepPomArtifact,
           includeSignatures = includeSignatures,
           classpathOrder = classpathOrder,
+          missingOk = missingOk
         )
 
         val reports0 = subRes.rootDependencies match {

modules/lm-coursier/src/main/scala/lmcoursier/internal/UpdateParams.scala

@@ -19,6 +19,7 @@ final case class UpdateParams(
   includeSignatures: Boolean,
   sbtBootJarOverrides: Map[(Module, String), File],
   classpathOrder: Boolean,
+  missingOk: Boolean
 ) {
 
   def artifactFileOpt(
@@ -38,7 +39,11 @@ final case class UpdateParams(
       else
         None
 
-    fromBootJars.orElse(artifacts.get(artifact))
+    val artifact0 =
+      if (missingOk) artifact.withOptional(true)
+      else artifact
+
+    fromBootJars.orElse(artifacts.get(artifact0))
   }
 
 }

modules/lm-coursier/src/main/scala/lmcoursier/internal/UpdateRun.scala

@@ -96,6 +96,7 @@ object UpdateRun {
       log,
       includeSignatures = params.includeSignatures,
       classpathOrder = params.classpathOrder,
+      missingOk = params.missingOk
     )
   }