1 files changed, 32 insertions, 0 deletions
diff --git a/python/private/which.bzl b/python/private/which.bzl
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+++ b/python/private/which.bzl
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+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Wrapper for repository which call"""
+
+_binary_not_found_msg = "Unable to find the binary '{binary_name}'.  Please update your PATH to include '{binary_name}'."
+
+def which_with_fail(binary_name, rctx):
+    """Tests to see if a binary exists, and otherwise fails with a message.
+
+    Args:
+        binary_name: name of the binary to find.
+        rctx: repository context.
+
+    Returns:
+        rctx.Path for the binary.
+    """
+    binary = rctx.which(binary_name)
+    if binary == None:
+        fail(_binary_not_found_msg.format(binary_name = binary_name))
+    return binary