尝试执行编译任务，但无法加载神秘模块

Question

我正在编译一个多部分的Scala项目。它不是很大，但是有些是Scala 2.13，有些是Scala 3。

尝试编译会产生致命错误[UNRESOLVED DEPENDENCIES:base#base_2.12;0.1.0-SNAPSHOT: not found]

问题是，字符串{0.1.0-SNAPSHOT}没有出现在我的构建中的任何地方。SBT或其他任何地方。它使用在那里，但它早就不见了。我假设一些更新缓存包含它，但我一直无法找到它。

这里是我的{build.sbt}:

ThisBuild / libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.7" % Test
ThisBuild / Compile / scalacOptions ++= Seq("--deprecation")
ThisBuild / Test / logBuffered := false
ThisBuild / Test / parallelExecution := false
lazy val scala213 = "2.13.5"
lazy val scala212 = "2.12.13"
lazy val scala3 = "3.0.0-RC2"
lazy val supportedScalaVersions = List(scala213, scala3)
lazy val root = (project in file("."))
.aggregate(top, trans, base)
.settings(
name := "toysat"
)
lazy val top = (project in file("top"))
.settings(
name := "main",
scalaVersion := scala213,
scalacOptions += "-Ytasty-reader",
libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.7" % Test
)
.dependsOn(trans, base)
lazy val trans = (project in file("trans"))
.settings(
name := "trans",
Compile / scalaVersion := scala3,
libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.7" % Test
).
dependsOn(base)
lazy val base = (project in file("base"))
.settings(
name := "base",
scalaVersion := scala213,
libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.7" % Test

在stackoverflow上，大多数这类问题都是关于下载远程定义模块的。我遇到的问题是，sbt找不到我的一个(新编译的)模块的过时版本。

，下面是sbt命令输出(这是一个Emacs缓冲区):

sbt:toysat> reload
[info] welcome to sbt 1.5.5 (AdoptOpenJDK Java 1.8.0_292)
[info] loading project definition from /Users/drewmcdermott/BIG/RESEARCH/puzzles/toystory4/toysat/project
[info] loading settings for project root from build.sbt ...
[info] set current project to toysat (in build file:/Users/drewmcdermott/BIG/RESEARCH/puzzles/toystory4/toysat/)
sbt:toysat> compile
[info] compiling 4 Scala sources to /Users/drewmcdermott/BIG/RESEARCH/puzzles/toystory4/toysat/base/target/scala-2.13/classes ...
[warn] 
[warn]  Note: Unresolved dependencies path:
[info] done compiling
[error] stack trace is suppressed; run last trans / update for the full output
[error] (trans / update) sbt.librarymanagement.ResolveException: Error downloading base:base_2.12:0.1.0-SNAPSHOT
[error]   Not found
[error]   Not found
[error]   not found: /Users/drewmcdermott/.ivy2/localbase/base_2.12/0.1.0-SNAPSHOT/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/base/base_2.12/0.1.0-SNAPSHOT/base_2.12-0.1.0-SNAPSHOT.pom
[error] Total time: 25 s, completed Jul 28, 2021 11:06:18 PM

编译base子项目中的4个文件花费了25秒，显然成功了。我认为是当sbt试图编译trans子项目时，它遇到了麻烦。

这是部分堆栈跟踪。我只知道Coursier与此事有关。

sbt:toysat> last trans / update
[debug] not up to date. inChanged = true, force = false
[debug] Updating trans...
[warn] 
[warn]  Note: Unresolved dependencies path:
[error] sbt.librarymanagement.ResolveException: Error downloading base:base_2.12:0.1.0-SNAPSHOT
[error]   Not found
[error]   Not found
[error]   not found: /Users/drewmcdermott/.ivy2/localbase/base_2.12/0.1.0-SNAPSHOT/ivys/ivy.xml
[error]   not found: https://repo1.maven.org/maven2/base/base_2.12/0.1.0-SNAPSHOT/base_2.12-0.1.0-SNAPSHOT.pom
[error]     at lmcoursier.CoursierDependencyResolution.unresolvedWarningOrThrow(CoursierDependencyResolution.scala:258)
[error]     at lmcoursier.CoursierDependencyResolution.$anonfun$update$38(CoursierDependencyResolution.scala:227)
[error]     at lmcoursier.CoursierDependencyResolution$$Lambda$4262/0x0000000000000000.apply(Unknown Source)
[error]     at scala.util.Either$LeftProjection.map(Either.scala:573)
[error]     at lmcoursier.CoursierDependencyResolution.update(CoursierDependencyResolution.scala:227)
[error]     at sbt.librarymanagement.DependencyResolution.update(DependencyResolution.scala:60)
[error]     at sbt.internal.LibraryManagement$.resolve$1(LibraryManagement.scala:59)

似乎很清楚，一些缓存在某处持有的字符串0.1.0-SNAPSHOT，但有一个惊人的数量的缓存。我试着删除了几个，但我还没有找到相关的。

谁能解释一下如何从这种情况中恢复过来?

Answer 1

您的base项目仅为Scala 2.13编译，而它被定义为针对Scala 3的trans的依赖项(使用dependsOn)。

你应该为Scala 2.13和3交叉构建你的base项目(根据你的错误信息可能是2.12，尽管我在你分享的内容中没有看到任何Scala 2.12的使用)。

编辑:Scala 2.13和3是兼容的，所以只有当一个依赖项只针对2.12构建时才会发生这个问题。

Answer 2

我不是在回答我自己的问题，因为我是一个自恋狂，而是因为我不能在评论中说出我想要的。另外，修改原来的问题会把可能有用的信息隐藏在一个奇怪的地方。我已经为@GaelJ的回答点赞了。

我的构建。SBT看起来没什么不同。这些差异可以通过显示修改后的trans子项目定义来概括:

lazy val trans = (projectMatrix in file("trans"))
.settings(
name := "trans",
version := "0.3",
// I thought this line was unnecessary, but without 
// it sbt doesn't understand the command trans / compile --
Compile / scalaVersion := scala3,
libraryDependencies += "org.scalatest" %% "scalatest" % "3.2.7" % Test
)
.jvmPlatform(scalaVersions = Seq(scala213))
.dependsOn(base)