buck2: re: Conditionally set re_dynamic_image

Summary: Per https://fb.workplace.com/groups/asiccompute/posts/1107047040663368/ , ASIC has pinned their version of buck2 due to S473397. That pinned version doesn't support this attribute, so let's conditionally set this if `CommandExecutorConfig` has it.

Reviewed By: wtetzner

Differential Revision: D67774608

fbshipit-source-id: a35328acc0a14236e5ab7da4c9a167be7345f7fd

prelude/tests/re_utils.bzl

@@ -90,6 +90,12 @@ def get_re_executors_from_props(ctx: AnalysisContext) -> ([CommandExecutorConfig
     if build_mode_info != None:
         remote_execution_action_key = "{}={}".format(build_mode_info.cell, build_mode_info.mode)
 
+    # HACK: We have some older pinned versions of buck2 out in the wild that don't
+    # support this key; let's conditionally set it for now.
+    kwargs = {}
+    if "remote_execution_dynamic_image" in dir(CommandExecutorConfig):
+        kwargs["remote_execution_dynamic_image"] = re_dynamic_image
+
     default_executor = CommandExecutorConfig(
         local_enabled = local_enabled,
         remote_enabled = True,
@@ -99,7 +105,7 @@ def get_re_executors_from_props(ctx: AnalysisContext) -> ([CommandExecutorConfig
         remote_execution_action_key = remote_execution_action_key,
         remote_execution_dependencies = re_dependencies,
         remote_execution_resource_units = re_resource_units,
-        remote_execution_dynamic_image = re_dynamic_image,
+        **kwargs
     )
     listing_executor = default_executor
     if listing_capabilities:
@@ -111,6 +117,6 @@ def get_re_executors_from_props(ctx: AnalysisContext) -> ([CommandExecutorConfig
             remote_cache_enabled = remote_cache_enabled,
             remote_execution_action_key = remote_execution_action_key,
             remote_execution_resource_units = re_resource_units,
-            remote_execution_dynamic_image = re_dynamic_image,
+            **kwargs
         )
     return default_executor, {"listing": listing_executor}