Update merge import baseline

Use exact list of files to create merge import baseline from singlepatch

PiperOrigin-RevId: 582018725
Change-Id: I8eff15d3265bda615ad6a60503ba5e3102c976d9

Author: jeyoungk

java/com/google/copybara/WorkflowRunHelper.java

@@ -980,20 +980,21 @@ static Glob singlePatchGlob(Workflow<? extends Revision, ? extends Revision> wor
 
     private Path checkoutSinglePatchBaseline(DestinationReader reader)
         throws ValidationException, IOException, RepoException {
-      // copy the current destination files to the baseline directory
-      Glob baselineFiles = patchlessDestinationFiles(workflow);
-
-      Path baselineWorkdir = Files.createDirectories(workdir.resolve("baseline"));
-      reader.copyDestinationFilesToDirectory(baselineFiles, baselineWorkdir);
-
-      // copy the singlepatch file from the destination to a separate directory
       Path singlepatchWorkdir = Files.createDirectories(workdir.resolve("singlepatch"));
-      reader.copyDestinationFilesToDirectory(singlePatchGlob(workflow), singlepatchWorkdir);
       Path singlePatchPath = singlepatchWorkdir.resolve(workflow.fullSinglePatchPath());
 
+      // copy the singlepatch file somewhere so we can parse it
+      reader.copyDestinationFilesToDirectory(singlePatchGlob(workflow), singlepatchWorkdir);
       SinglePatch singlePatch =
           SinglePatch.fromBytes(
               Files.readAllBytes(singlePatchPath));
+
+      // copy the current destination files to the baseline directory
+      Glob baselineFiles = Glob.createGlob(singlePatch.getFileHashes().keySet().asList());
+
+      Path baselineWorkdir = Files.createDirectories(workdir.resolve("baseline"));
+      reader.copyDestinationFilesToDirectory(baselineFiles, baselineWorkdir);
+
       singlePatch.validateDirectory(SinglePatch.filesInDir(baselineWorkdir), reader::getHash);
       singlePatch.reverseSinglePatch(
           baselineWorkdir, workflow.getGeneralOptions().getEnvironment());

java/com/google/copybara/util/SinglePatch.java

@@ -145,7 +145,7 @@ public static SinglePatch fromBytes(byte[] bytes)
     }
   }
 
-  ImmutableMap<String, String> getFileHashes() {
+  public ImmutableMap<String, String> getFileHashes() {
     return ImmutableMap.copyOf(fileHashes);
   }