build-release-notes: fail if the directory does not exist

This was a combination of two problems: the python didn't throw an error
because apparently glob on a nonexistent directory doesn't crash, and
secondarily, bash ignores bad exit codes without `set -e` if they are
not in the final/only command.

Change-Id: I812bde7a4daee5c77ffe9d7c73a25fd14969f548

1 files changed, 4 insertions, 1 deletions

diff --git a/maintainers/build-release-notes.py b/maintainers/build-release-notes.py
index 85bc40aba..311dca803 100644
--- a/maintainers/build-release-notes.py
+++ b/maintainers/build-release-notes.py
@@ -40,7 +40,10 @@ def plural_list(strs: list[str]) -> str:
         return '{}{} and {}'.format(', '.join(strs[:-1]), comma, strs[-1])
 
 def run_on_dir(d):
-    paths = pathlib.Path(d).glob('*.md')
+    d = pathlib.Path(d)
+    if not d.is_dir():
+        raise ValueError(f'provided path {d} is not a directory')
+    paths = d.glob('*.md')
     entries = []
     for p in paths:
         try: