Add support for providing the raw String of a commit SHA as a comparison strategy

Author: ivanalvarado

affectedmoduledetector/src/main/kotlin/com/dropbox/affectedmoduledetector/AffectedModuleConfiguration.kt

@@ -81,13 +81,16 @@ class AffectedModuleConfiguration {
 
     var specifiedBranch: String? = null
 
+    var specifiedRawCommitSha: String? = null
+
     var compareFrom: String = "PreviousCommit"
         set(value) {
             val commitShaProviders = listOf(
                 "PreviousCommit",
                 "ForkCommit",
                 "SpecifiedBranchCommit",
-                "SpecifiedBranchCommitMergeBase"
+                "SpecifiedBranchCommitMergeBase",
+                "SpecifiedRawCommitSha"
             )
             require(commitShaProviders.contains(value)) {
                 "The property configuration compareFrom must be one of the following: ${commitShaProviders.joinToString(", ")}"
@@ -97,6 +100,11 @@ class AffectedModuleConfiguration {
                     "Specify a branch using the configuration specifiedBranch"
                 }
             }
+            if (value == "SpecifiedRawCommitSha") {
+                requireNotNull(specifiedRawCommitSha) {
+                    "Provide a Commit SHA for the specifiedRawCommitSha property when using SpecifiedRawCommitSha comparison strategy."
+                }
+            }
             field = value
         }
 

affectedmoduledetector/src/main/kotlin/com/dropbox/affectedmoduledetector/AffectedModuleDetector.kt

@@ -340,7 +340,7 @@ class AffectedModuleDetectorImpl constructor(
         injectedGitClient ?: GitClientImpl(
             rootProject.projectDir,
             logger,
-            commitShaProvider = CommitShaProvider.fromString(config.compareFrom, config.specifiedBranch),
+            commitShaProvider = CommitShaProvider.fromString(config.compareFrom, config.specifiedBranch, config.specifiedRawCommitSha),
             ignoredFiles = config.ignoredFiles
         )
     }

affectedmoduledetector/src/main/kotlin/com/dropbox/affectedmoduledetector/commitshaproviders/CommitShaProvider.kt

@@ -8,7 +8,11 @@ interface CommitShaProvider {
     fun get(commandRunner: GitClient.CommandRunner): Sha
 
     companion object {
-        fun fromString(string: String, specifiedBranch: String? = null): CommitShaProvider {
+        fun fromString(
+            string: String,
+            specifiedBranch: String? = null,
+            specifiedRawCommitSha: String? = null
+        ): CommitShaProvider {
             return when (string) {
                 "PreviousCommit" -> PreviousCommit()
                 "ForkCommit" -> ForkCommit()
@@ -24,6 +28,12 @@ interface CommitShaProvider {
                     }
                     SpecifiedBranchCommitMergeBase(specifiedBranch)
                 }
+                "SpecifiedRawCommitSha" -> {
+                    requireNotNull(specifiedRawCommitSha) {
+                        "Specified raw commit sha must be defined"
+                    }
+                    SpecifiedRawCommitSha(specifiedRawCommitSha)
+                }
                 else -> throw IllegalArgumentException("Unsupported compareFrom type")
             }
         }

affectedmoduledetector/src/main/kotlin/com/dropbox/affectedmoduledetector/commitshaproviders/SpecifiedRawCommitSha.kt

@@ -0,0 +1,10 @@
+package com.dropbox.affectedmoduledetector.commitshaproviders
+
+import com.dropbox.affectedmoduledetector.GitClient
+import com.dropbox.affectedmoduledetector.Sha
+
+class SpecifiedRawCommitSha(private val commitSha: String) : CommitShaProvider {
+    override fun get(commandRunner: GitClient.CommandRunner): Sha {
+        return commitSha
+    }
+}