experiment: env vars only

lib/private/run_binary.bzl

diff --git a/lib/private/run_binary.bzl b/lib/private/run_binary.bzl
index 3016790..1eb8074 100644
--- a/lib/private/run_binary.bzl
+++ b/lib/private/run_binary.bzl
@@ -59,13 +59,14 @@
     for k, v in ctx.attr.env.items():
         envs[k] = " ".join([expand_variables(ctx, e, outs = outputs, attribute_name = "env") for e in expand_locations(ctx, v, ctx.attr.srcs).split(" ")])
 
+    inputs = ctx.files.srcs
+
     stamp = maybe_stamp(ctx)
     if stamp:
-        inputs = ctx.files.srcs + [stamp.volatile_status_file, stamp.stable_status_file]
-        envs["BAZEL_STABLE_STATUS_FILE"] = stamp.stable_status_file.path
         envs["BAZEL_VOLATILE_STATUS_FILE"] = stamp.volatile_status_file.path
-    else:
-        inputs = ctx.files.srcs
+        envs["BAZEL_STABLE_STATUS_FILE"] = stamp.stable_status_file.path
+        if not stamp.env_vars_only:
+            inputs = inputs + [stamp.stable_status_file, stamp.volatile_status_file]
 
     ctx.actions.run(
         outputs = outputs,

lib/stamping.bzl

diff --git a/lib/stamping.bzl b/lib/stamping.bzl
index b54977d..ff777a2 100644
--- a/lib/stamping.bzl
+++ b/lib/stamping.bzl
@@ -103,6 +103,7 @@
         return struct(
             volatile_status_file = ctx.version_file,
             stable_status_file = ctx.info_file,
+            stamp_volatile_only = ctx.attr.stamp_volatile_only,
         )
 
     return None
@@ -126,6 +127,7 @@
         default = -1,
         values = [1, 0, -1],
     ),
+    "env_vars_only": attr.bool(),
     "_stamp_flag": attr.label(
         doc = "Internal use only. A setting used to determine whether or not the `--stamp` flag is enabled.",
         default = Label("//lib:stamp"),