Validate that inline snapshot source is within source directory. (#6)

* Validate that inline snapshot source is within source directory.

* Update modules/core/src/main/scala/com/siriusxm/snapshot4s/SnapshotConfigError.scala

Co-authored-by: Michał Pawlik <[email protected]>

* Add comments and extend Exception.

---------

Co-authored-by: Michał Pawlik <[email protected]>

build.sbt

@@ -107,8 +107,10 @@ lazy val core = (projectMatrix in file("modules/core"))
   .jvmPlatform(
     scalaVersions = scalaVersions,
     libraryDependencies += "com.lihaoyi" %% "os-lib" % Versions.oslib
+  ).jsPlatform(scalaVersions = scalaVersions,
+    // module support is required to run tests
+    Test / scalaJSLinkerConfig ~= { _.withModuleKind(ModuleKind.CommonJSModule) }
   )
-  .jsPlatform(scalaVersions = scalaVersions)
 
 lazy val munit = (projectMatrix in file("modules/munit"))
   .settings(

modules/core/src/main/scala/com/siriusxm/snapshot4s/InlineSnapshot.scala

@@ -84,13 +84,15 @@ object InlineSnapshot {
     changeFile.write(actualStr)
   }
 
-  private def relativeSourceFilePath(
+  private[snapshot4s] def relativeSourceFilePath(
       sourceFile: String,
       config: SnapshotConfig
   ): RelPath = {
     val baseDirectory  = config.sourceDirectory
     val sourceFilePath = Path(sourceFile)
-    sourceFilePath.relativeTo(baseDirectory)
+    sourceFilePath.relativeTo(baseDirectory).getOrElse {
+      throw new SnapshotConfigUnsupportedError(config)
+    }
   }
 
   // See the Scala 2.13 compiler for the source of the warning we're ignoring:

modules/core/src/main/scala/com/siriusxm/snapshot4s/PathApi.scala

@@ -20,16 +20,22 @@ private[snapshot4s] trait PathApi {
 
   private[snapshot4s] def read(): String
   private[snapshot4s] def write(contents: String): Unit
-  private[snapshot4s] def relativeTo(baseDirectory: Path): RelPath
+  private[snapshot4s] def relativeTo(baseDirectory: Path): Option[RelPath]
   private[snapshot4s] def /(path: RelPath): Path
 
   private[snapshot4s] def exists(): Boolean
+
+  private[snapshot4s] def value: String
 }
 
 trait PathCompanionApi {
   def apply(path: String): Path
 }
 
+private[snapshot4s] trait RelPathApi {
+  private[snapshot4s] def value: String
+}
+
 private[snapshot4s] trait RelPathCompanionApi {
   def apply(path: String): RelPath
 }

modules/core/src/main/scala/com/siriusxm/snapshot4s/SnapshotConfigError.scala

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2024 SiriusXM
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package snapshot4s
+
+private final class SnapshotConfigUnsupportedError(config: SnapshotConfig) extends Exception({
+      s"""Your project setup is not supported by snapshot4s. We encourage you to raise an issue at https://github.com/siriusxm/snapshot4s.
+
+We have detected the following configuration:
+  - sourceDirectory: ${config.sourceDirectory.value}
+  - resourceDirectory: ${config.resourceDirectory.value}
+  - outputDirectory: ${config.outputDirectory.value}
+"""
+    })

modules/core/src/main/scalajs/com/siriusxm/snapshot4s/Path.scala

@@ -42,14 +42,23 @@ final class Path private (override val toString: String) extends PathApi {
     )
   }
 
-  private[snapshot4s] def relativeTo(baseDirectory: Path): RelPath =
-    RelPath(facade.relative(baseDirectory.toString, toString))
+  private[snapshot4s] def relativeTo(baseDirectory: Path): Option[RelPath] = {
+    val text = facade.relative(baseDirectory.toString, toString)
+    // Check that this path is in a subdirectory of the base directory.
+    if (text.startsWith("../")) {
+      None
+    } else {
+      Some(RelPath(text))
+    }
+  }
 
   private[snapshot4s] def /(path: RelPath): Path =
     Path(facade.join(toString, path.toString))
 
   private[snapshot4s] def exists(): Boolean =
     facade.exists(toString)
+
+  private[snapshot4s] def value: String = toString
 }
 
 object Path extends PathCompanionApi {

modules/core/src/main/scalajs/com/siriusxm/snapshot4s/RelPath.scala

@@ -16,7 +16,9 @@
 
 package snapshot4s
 
-private[snapshot4s] final class RelPath private (override val toString: String)
+private[snapshot4s] final class RelPath private (override val toString: String) extends RelPathApi {
+  private[snapshot4s] def value: String = toString
+}
 
 private[snapshot4s] object RelPath extends RelPathCompanionApi {
   def apply(path: String): RelPath = new RelPath(path)

modules/core/src/main/scalajvm/com/siriusxm/snapshot4s/Path.scala

@@ -23,13 +23,17 @@ final class Path private[snapshot4s] (val osPath: os.Path) extends PathApi {
   private[snapshot4s] def write(contents: String): Unit =
     os.write.over(osPath, contents, createFolders = true)
 
-  private[snapshot4s] def relativeTo(baseDirectory: Path): RelPath =
-    new RelPath(osPath.relativeTo(baseDirectory.osPath))
+  private[snapshot4s] def relativeTo(baseDirectory: Path): Option[RelPath] =
+    if (osPath.startsWith(baseDirectory.osPath))
+      Some(new RelPath(osPath.relativeTo(baseDirectory.osPath)))
+    else None
 
   private[snapshot4s] def /(path: RelPath): Path =
     new Path(osPath / path.osPath)
 
   def exists(): Boolean = os.exists(osPath)
+
+  private[snapshot4s] def value: String = osPath.toString
 }
 
 object Path extends PathCompanionApi {

modules/core/src/main/scalajvm/com/siriusxm/snapshot4s/RelPath.scala

@@ -16,7 +16,9 @@
 
 package snapshot4s
 
-private[snapshot4s] final class RelPath(val osPath: os.PathChunk)
+private[snapshot4s] final class RelPath(val osPath: os.PathChunk) extends RelPathApi {
+  private[snapshot4s] def value: String = osPath.toString
+}
 
 object RelPath extends RelPathCompanionApi {
   def apply(path: String): RelPath =

modules/core/src/test/scala/com/siriusxm/snapshot4s/InlineSnapshotSpec.scala

@@ -0,0 +1,42 @@
+package snapshot4s
+
+import cats.effect.IO
+import weaver.*
+
+object InlineSnapshotSpec extends SimpleIOSuite {
+
+  pureTest("calculates relative paths correctly") {
+    val config = new SnapshotConfig(
+      resourceDirectory = Path("/path/to/resources"),
+      outputDirectory = Path("/path/to/output"),
+      sourceDirectory = Path("/path/to/sources")
+    )
+    val relativePath =
+      InlineSnapshot.relativeSourceFilePath("/path/to/sources/TestFile.scala", config)
+    expect.eql(relativePath.value, "TestFile.scala")
+  }
+
+  test("raises errors if the source directory is calculated incorrectly") {
+    val config = new SnapshotConfig(
+      resourceDirectory = Path("/path/to/resources"),
+      outputDirectory = Path("/path/to/output"),
+      sourceDirectory = Path("/wrong/path/to/sources")
+    )
+    val result =
+      IO(InlineSnapshot.relativeSourceFilePath("/path/to/sources/TestFile.scala", config))
+    val message =
+      """Your project setup is not supported by snapshot4s. We encourage you to raise an issue at https://github.com/siriusxm/snapshot4s.
+
+We have detected the following configuration:
+  - sourceDirectory: /wrong/path/to/sources
+  - resourceDirectory: /path/to/resources
+  - outputDirectory: /path/to/output
+"""
+    result.attempt.map { result =>
+      matches(result) { case Left(err) =>
+        expect.eql(err.getMessage, message)
+      }
+    }
+
+  }
+}