sandbox: Deprecate the --eager-package-loading flag. (#11404)

It never did anything in Sandbox Next. Packages are always loaded
eagerly in KV ledgers.

CHANGELOG_BEGIN
- [Sandbox] The ``--eager-package-loading`` flag has been deprecated. It
  hasn't actually done anything for many releases; packages are always
  loaded eagerly. This does not affect Daml on SQL, which does support
  lazy package loading.
CHANGELOG_END

ledger/daml-on-sql/src/main/scala/on/sql/Cli.scala

@@ -20,6 +20,14 @@ private[sql] final class Cli(
         .withContractIdSeeding(defaultConfig, Some(Seeding.Strong), Some(Seeding.Weak))
         .parser
 
+    parser
+      .opt[Unit]("eager-package-loading")
+      .optional()
+      .text(
+        "Whether to load all the packages in the .dar files provided eagerly, rather than when needed as the commands come."
+      )
+      .action((_, config) => config.copy(eagerPackageLoading = true))
+
     parser
       .opt[String]("sql-backend-jdbcurl-env")
       .optional()

ledger/daml-on-sql/src/test/suite/scala/on/sql/CliSpec.scala

@@ -54,6 +54,10 @@ class CliSpec
       config shouldEqual None
     }
 
+    "parse the eager package loading flag when given" in {
+      checkOption(Array("--eager-package-loading"), _.copy(eagerPackageLoading = true))
+    }
+
     "reject when sql-backend-jdbcurl-env points to a non-existing environment variable" in {
       val config =
         cli.parse(Array("--ledgerid", "test-ledger", "--sql-backend-jdbcurl-env", "JDBC_URL"))

ledger/sandbox-classic/src/main/scala/platform/sandbox/Cli.scala

@@ -32,6 +32,13 @@ private[sandbox] object Cli extends SandboxCli {
           " Two identifier formats are supported: Module.Name:Entity.Name (preferred) and Module.Name.Entity.Name (deprecated, will print a warning when used)." +
           s" Also note that instructing $Name to load a scenario will have the side effect of loading _all_ the .dar files provided eagerly (see --eager-package-loading)."
       )
+    parser
+      .opt[Unit]("eager-package-loading")
+      .optional()
+      .text(
+        "Whether to load all the packages in the .dar files provided eagerly, rather than when needed as the commands come."
+      )
+      .action((_, config) => config.copy(eagerPackageLoading = true))
     parser
       .opt[String]("sql-backend-jdbcurl")
       .optional()

ledger/sandbox-classic/src/test/suite/scala/platform/sandbox/CliSpec.scala

@@ -23,6 +23,10 @@ class CliSpec extends CommonCliSpecBase(Cli) {
       )
     }
 
+    "parse the eager package loading flag when given" in {
+      checkOption(Array("--eager-package-loading"), _.copy(eagerPackageLoading = true))
+    }
+
     "parse the sql-backend-jdbcurl flag when given" in {
       val jdbcUrl = "jdbc:postgresql://localhost:5432/test?user=test"
       checkOption(Array("--sql-backend-jdbcurl", jdbcUrl), _.copy(jdbcUrl = Some(jdbcUrl)))

ledger/sandbox-common/src/main/scala/platform/sandbox/cli/CommonCliBase.scala

@@ -237,13 +237,6 @@ class CommonCliBase(name: LedgerName) {
 
       com.daml.cliopts.Logging.logLevelParse(this)((f, c) => c.copy(logLevel = f(c.logLevel)))
 
-      opt[Unit]("eager-package-loading")
-        .optional()
-        .text(
-          "Whether to load all the packages in the .dar files provided eagerly, rather than when needed as the commands come."
-        )
-        .action((_, config) => config.copy(eagerPackageLoading = true))
-
       JwtVerifierConfigurationCli.parse(this)((v, c) =>
         c.copy(authService = Some(AuthServiceJWT(v)))
       )

ledger/sandbox-common/src/test/lib/scala/platform/sandbox/cli/CommonCliSpecBase.scala

@@ -207,10 +207,6 @@ abstract class CommonCliSpecBase(
       )
     }
 
-    "parse the eager package loading flag when given" in {
-      checkOption(Array("--eager-package-loading"), _.copy(eagerPackageLoading = true))
-    }
-
     "parse a console metrics reporter when given" in {
       checkOption(
         Array("--metrics-reporter", "console"),

ledger/sandbox/BUILD.bazel

@@ -263,15 +263,13 @@ NEXT_SERVERS = {
         "server_args": [
             "--contract-id-seeding=testing-weak",
             "--port=6865",
-            "--eager-package-loading",
         ],
     },
     "postgresql": {
         "binary": ":sandbox-ephemeral-postgresql",
         "server_args": [
             "--contract-id-seeding=testing-weak",
             "--port=6865",
-            "--eager-package-loading",
         ],
     },
 }

ledger/sandbox/src/main/scala/platform/sandboxnext/Cli.scala

@@ -21,6 +21,19 @@ private[sandboxnext] object Cli extends SandboxCli {
         Some(Seeding.Static),
       )
       .parser
+
+    parser
+      .opt[Unit]("eager-package-loading")
+      .hidden()
+      .optional()
+      .text("Deprecated. This flag no longer has any effect.")
+      .action((_, config) => {
+        System.err.println(
+          "WARNING: The `--eager-package-loading` flag no longer has any effect in the Sandbox. Packages are always loaded eagerly."
+        )
+        config
+      })
+
     parser
       .opt[Boolean](name = "implicit-party-allocation")
       .optional()
@@ -29,6 +42,7 @@ private[sandboxnext] object Cli extends SandboxCli {
         s"When referring to a party that doesn't yet exist on the ledger, $Name will implicitly allocate that party."
           + s" You can optionally disable this behavior to bring $Name into line with other ledgers."
       )
+
     parser
       .opt[String]("sql-backend-jdbcurl")
       .optional()