Introduced a new utility just to retrieve the test targets for the se…

…t of changed files provided

Since the code coverages take a long time, it should be possible that the builds are taking the most times which cause process didn't finish within intended time errors. So may be having the build oppia tests beforehand should help with this, but since we use just the changed files for the input to our run coverage scripts we will need this extra utility (or if possible lets try to move it with something else if possible retrieve changed files.kt) to handle the mapping of changed files to their respective targets to feed to build them

.github/workflows/code_coverage.yml

@@ -153,6 +153,21 @@ jobs:
           echo "FILE_CACHING_BUCKET=$FILE_CATEGORY" >> $GITHUB_ENV
           echo "CHANGED_FILES=$CHANGED_FILES" >> $GITHUB_ENV
 
+      - name: Extract test caching bucket & changed files test targets
+        env:
+          CHANGED_FILESS_BUCKET_BASE64_ENCODED_SHARD: ${{ matrix.changed-files-bucket-base64-encoded-shard }}
+        run: |
+          # See https://stackoverflow.com/a/29903172 for cut logic. This is needed to remove the
+          # user-friendly shard prefix from the matrix value.
+          CHANGED_FILES_TEST_TARGETS_BUCKET_BASE64=$(echo "$CHANGED_FILESS_BUCKET_BASE64_ENCODED_SHARD" | cut -d ";" -f 2)
+          bazel run //scripts:retrieve_changed_files_test_targets -- $(pwd) $CHANGED_FILES_TEST_TARGETS_BUCKET_BASE64 $(pwd)/test_bucket_name $(pwd)/bazel_test_targets
+          TEST_CATEGORY=$(cat ./test_bucket_name)
+          BAZEL_TEST_TARGETS=$(cat ./bazel_test_targets)
+          echo "Test category: $TEST_CATEGORY"
+          echo "Bazel test targets: $BAZEL_TEST_TARGETS"
+          echo "TEST_CACHING_BUCKET=$TEST_CATEGORY" >> $GITHUB_ENV
+          echo "BAZEL_TEST_TARGETS=$BAZEL_TEST_TARGETS" >> $GITHUB_ENV
+
       # For reference on this & the later cache actions, see:
       # https://github.com/actions/cache/issues/239#issuecomment-606950711 &
       # https://github.com/actions/cache/issues/109#issuecomment-558771281. Note that these work

scripts/BUILD.bazel

@@ -80,6 +80,13 @@ kt_jvm_binary(
     runtime_deps = ["//scripts/src/java/org/oppia/android/scripts/ci:retrieve_changed_files_lib"],
 )
 
+kt_jvm_binary(
+    name = "retrieve_changed_files_test_targets",
+    testonly = True,
+    main_class = "org.oppia.android.scripts.ci.RetrieveChangedFilesTestTargetsKt",
+    runtime_deps = ["//scripts/src/java/org/oppia/android/scripts/ci:retrieve_changed_files_test_targets_lib"],
+)
+
 # TODO(#3428): Refactor textproto assets to subpackage level.
 REGEX_PATTERN_CHECK_ASSETS = generate_regex_assets_list_from_text_protos(
     name = "regex_asset_files",

scripts/src/java/org/oppia/android/scripts/ci/BUILD.bazel

@@ -58,3 +58,17 @@ kt_jvm_library(
         "//scripts/src/java/org/oppia/android/scripts/proto:changed_files_java_proto",
     ],
 )
+
+kt_jvm_library(
+    name = "retrieve_changed_files_test_targets_lib",
+    testonly = True,
+    srcs = [
+        "RetrieveChangedFilesTestTargets.kt",
+    ],
+    visibility = ["//scripts:oppia_script_binary_visibility"],
+    deps = [
+        "//scripts/src/java/org/oppia/android/scripts/common:bazel_client",
+        "//scripts/src/java/org/oppia/android/scripts/common:proto_string_encoder",
+        "//scripts/src/java/org/oppia/android/scripts/proto:changed_files_java_proto",
+    ],
+)

scripts/src/java/org/oppia/android/scripts/ci/RetrieveChangedFilesTestTargets.kt

@@ -0,0 +1,68 @@
+package org.oppia.android.scripts.ci
+
+import org.oppia.android.scripts.common.BazelClient
+import org.oppia.android.scripts.common.CommandExecutor
+import org.oppia.android.scripts.common.CommandExecutorImpl
+import org.oppia.android.scripts.common.ProtoStringEncoder.Companion.mergeFromCompressedBase64
+import org.oppia.android.scripts.proto.ChangedFilesBucket
+import java.io.File
+import java.util.Locale
+import java.util.concurrent.TimeUnit
+import kotlin.system.exitProcess
+
+/**
+ * The main entrypoint for retrieving the list of changed files from a particular encoded Base64
+ * bucket. This is used to parse the output from compute_changed_files.
+ *
+ * Usage:
+ *   bazel run //scripts:retrieve_changed_files -- \\
+ *     <encoded_proto_in_base64> <path_to_bucket_name_output_file> \\
+ *     <path_to_file_list_output_file>
+ *
+ * Arguments:
+ * - encoded_proto_in_base64: the compressed & Base64-encoded [ChangedFilesBucket] proto computed
+ *     by compute_changed_files.
+ * - path_to_bucket_name_output_file: path to the file where the file bucket name corresponding to
+ *     this bucket should be printed.
+ * - path_to_file_list_output_file: path to the file where the list of changed files
+ *     corresponding to this bucket should be printed.
+ *
+ * Example:
+ *   bazel run //scripts:retrieve_changed_files -- $(pwd) $CHANGED_FILES_BUCKETS_BASE64_ENCODED_PROTO \\
+ *     $(pwd)/file_bucket_name $(pwd)/changed_files
+ */
+fun main(args: Array<String>) {
+  /*if (args.size < 3) {
+    println(
+      "Usage: bazel run //scripts:retrieve_changed_files --" +
+        " <encoded_proto_in_base64> <path_to_bucket_name_output_file>" +
+        " <path_to_file_list_output_file>"
+    )
+    exitProcess(1)
+  }*/
+
+  val rootDirectory = File(args[0]).absoluteFile
+  val protoBase64 = args[1]
+  val bucketNameOutputFile = File(args[2])
+  val fileTestTargetsListOutputFile = File(args[3])
+
+  val commandExecutor: CommandExecutor =
+    CommandExecutorImpl(
+      scriptBgDispatcher, processTimeout = 5, processTimeoutUnit = TimeUnit.MINUTES
+    )
+
+  val bazelClient = BazelClient(rootDirectory, commandExecutor)
+
+  val changedFilesBucket =
+    ChangedFilesBucket.getDefaultInstance().mergeFromCompressedBase64(protoBase64)
+  bucketNameOutputFile.printWriter().use { writer ->
+    writer.println(changedFilesBucket.cacheBucketName)
+  }
+
+  val changedFilesTestTargets = bazelClient.retrieveBazelTargets(changedFilesBucket.changedFilesList)
+  println("Changed Files Test Targets: $changedFilesTestTargets")
+
+  fileTestTargetsListOutputFile.printWriter().use { writer ->
+    writer.println(changedFilesTestTargets.joinToString(separator = " "))
+  }
+}