Overridable debuginfo type

This change enables the override of the auto-detected `/etc/os-release`-based
`debuginfo` type and allows the auto-detection by means of a new  `default`
option.

This also enables the use of` none` as an override option.

Author: nicbadiu

toolchains/rpm/rpmbuild_configure.bzl

@@ -57,6 +57,7 @@ def _parse_release_info(release_info):
 
     return os_name, os_version
 
+DEBUGINFO_TYPE_DEFAULT = "default"
 DEBUGINFO_TYPE_NONE = "none"
 DEBUGINFO_TYPE_CENTOS = "centos"
 DEBUGINFO_TYPE_FEDORA = "fedora"
@@ -67,11 +68,25 @@ DEBUGINFO_TYPE_BY_OS_RELEASE = {
     "fedora": DEBUGINFO_TYPE_FEDORA,
 }
 
+DEBUGINFO_VALID_VALUES = [
+    DEBUGINFO_TYPE_FEDORA,
+    DEBUGINFO_TYPE_CENTOS,
+    DEBUGINFO_TYPE_NONE,
+    DEBUGINFO_TYPE_DEFAULT,
+]
+
 def _build_repo_for_rpmbuild_toolchain_impl(rctx):
-    debuginfo_type = DEBUGINFO_TYPE_NONE
-    if rctx.path(RELEASE_PATH).exists:
-        os_name, _ = _parse_release_info(rctx.read(RELEASE_PATH))
-        debuginfo_type = DEBUGINFO_TYPE_BY_OS_RELEASE.get(os_name, debuginfo_type)
+    if rctx.attr.debuginfo_type not in DEBUGINFO_VALID_VALUES:
+        fail("debuginfo_type must be one of", DEBUGINFO_VALID_VALUES)
+
+    debuginfo_type = rctx.attr.debuginfo_type
+    if debuginfo_type == DEBUGINFO_TYPE_DEFAULT:
+        rctx.watch(RELEASE_PATH)
+        if rctx.path(RELEASE_PATH).exists:
+            os_name, _ = _parse_release_info(rctx.read(RELEASE_PATH))
+            debuginfo_type = DEBUGINFO_TYPE_BY_OS_RELEASE.get(os_name, debuginfo_type)
+        else:
+            debuginfo_type = DEBUGINFO_TYPE_NONE
 
     rpmbuild_path = rctx.which("rpmbuild")
     if rctx.attr.verbose:
@@ -80,9 +95,6 @@ def _build_repo_for_rpmbuild_toolchain_impl(rctx):
         else:
             print("No system rpmbuild found.")  # buildifier: disable=print
 
-    if rctx.attr.debuginfo_type not in ["centos7", "fedora40", "none"]:
-        fail("debuginfo_type must be one of centos7, fedora40, or none")
-
     version = "unknown"
     if rpmbuild_path:
         res = rctx.execute([rpmbuild_path, "--version"])
@@ -112,9 +124,9 @@ build_repo_for_rpmbuild_toolchain = repository_rule(
             doc = """
             The underlying debuginfo configuration for the system rpmbuild.
 
-            One of `centos`, `fedora`, and `none`
+            One of `centos`, `fedora`, `none`, and `default` (which looks up `/etc/os-release`)
             """,
-            default = "none",
+            default = DEBUGINFO_TYPE_DEFAULT,
         ),
     },
 )