fix: override default since param only if explicitly provided by cli #36

952b5db introduced a regression, ignoring the `since` parameter defined
via YAML config in favor of the default defined by the cli option.

scriv.d/20230919_153108_ltvolks_since_default_override.rst

@@ -0,0 +1,8 @@
+Fixed
+.....
+
+- fix: override default since param only if explicitly provided by cli #36
+  952bdfb introduced a regression ignoring the `since` parameter defined via
+  YAML config in favor of the default defined by the cli option
+
+.. _issue 36: https://github.com/nedbat/dinghy/issues/36

src/dinghy/cli.py

@@ -45,12 +45,14 @@ def main_run(coro):
 @click.option(
     "--since",
     metavar="DELTA-OR-DATE",
-    help="Specify a since date [default: 1 week].",
+    help="Specify a since date.",
     default="1 week",
+    show_default=True,
 )
 @click.argument("_input", metavar="[INPUT]", default="dinghy.yaml")
 @click.argument("digests", metavar="[DIGEST ...]", nargs=-1)
-def cli(since, _input, digests):
+@click.pass_context
+def cli(ctx, since, _input, digests):
     """
     Generate HTML digests of GitHub activity.
 
@@ -64,6 +66,8 @@ def cli(since, _input, digests):
     if "://" in _input:
         coro = make_digest([_input], since=since)
     else:
+        source = ctx.get_parameter_source("since")
+        since = None if source.name == "DEFAULT" else since
         coro = make_digests_from_config(_input, digests or None, since=since)
 
     main_run(coro)