Allow the list of fine grained hashes to be defined by a file (#277)

* Allow the list of fine grained hashes to be defined by a file

* Make the flags mutually exclusive

Author: blockjon-dd

cli/src/main/kotlin/com/bazel_diff/cli/GenerateHashesCommand.kt

@@ -78,6 +78,13 @@ class GenerateHashesCommand : Callable<Int> {
   )
   var fineGrainedHashExternalRepos: Set<String> = emptySet()
 
+  @CommandLine.Option(
+        names = ["--fineGrainedHashExternalReposFile"],
+        description =
+            [
+                "A text file containing a newline separated list of external repos. Similar to --fineGrainedHashExternalRepos but helps you avoid exceeding max arg length. Mutually exclusive with --fineGrainedHashExternalRepos."])
+  var fineGrainedHashExternalReposFile: File? = null
+
   @CommandLine.Option(
       names = ["--useCquery"],
       negatable = true,
@@ -192,6 +199,7 @@ class GenerateHashesCommand : Callable<Int> {
               keepGoing,
               depsMappingJSONPath != null,
               fineGrainedHashExternalRepos,
+              fineGrainedHashExternalReposFile,
               excludeExternalTargets,
           ),
           loggingModule(parent.verbose),

cli/src/main/kotlin/com/bazel_diff/di/Modules.kt

@@ -30,8 +30,19 @@ fun hasherModule(
     keepGoing: Boolean,
     trackDeps: Boolean,
     fineGrainedHashExternalRepos: Set<String>,
+    fineGrainedHashExternalReposFile: File?,
     excludeExternalTargets: Boolean,
 ): Module = module {
+  if (fineGrainedHashExternalReposFile != null && fineGrainedHashExternalRepos.isNotEmpty()) {
+    System.err.println("Error: fineGrainedHashExternalReposFile and fineGrainedHashExternalRepos are mutually exclusive - please provide only one of them")
+    System.exit(1)
+  }
+  val updatedFineGrainedHashExternalRepos = fineGrainedHashExternalReposFile?.let { file ->
+    file.readLines()
+        .filter { it.isNotBlank() }
+        .toSet()
+  } ?: fineGrainedHashExternalRepos
+
   val cmd: MutableList<String> =
       ArrayList<String>().apply {
         add(bazelPath.toString())
@@ -60,11 +71,11 @@ fun hasherModule(
         keepGoing,
         debug)
   }
-  single { BazelClient(useCquery, fineGrainedHashExternalRepos, excludeExternalTargets) }
+  single { BazelClient(useCquery, updatedFineGrainedHashExternalRepos, excludeExternalTargets) }
   single { BuildGraphHasher(get()) }
   single { TargetHasher() }
-  single { RuleHasher(useCquery, trackDeps, fineGrainedHashExternalRepos) }
-  single<SourceFileHasher> { SourceFileHasherImpl(fineGrainedHashExternalRepos) }
+  single { RuleHasher(useCquery, trackDeps, updatedFineGrainedHashExternalRepos) }
+  single<SourceFileHasher> { SourceFileHasherImpl(updatedFineGrainedHashExternalRepos) }
   single { ExternalRepoResolver(workingDirectory, bazelPath, outputPath) }
   single(named("working-directory")) { workingDirectory }
   single(named("output-base")) { outputPath }