From 1439bec42aa08c6dd0c21e053486e15261c4da57 Mon Sep 17 00:00:00 2001
From: Christian Sutter <git@doublesignal.com>
Date: Fri, 18 Oct 2024 10:40:23 +0000
Subject: [PATCH] `DateParser`: Allow nil input

There are edge cases where a date parameter is provided but left empty,
e.g. `public_timestamp%5Bto%5D`. In those cases, rather than an empty
string (which would be the case for `public_timestamp%5Bto%5D=`), Rails
will return nil for the param's value, breaking `DateParser`.
---
 app/parsers/date_parser.rb       |  4 +++-
 spec/parsers/date_parser_spec.rb | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/app/parsers/date_parser.rb b/app/parsers/date_parser.rb
index 03a3b6bbd..625e6319d 100644
--- a/app/parsers/date_parser.rb
+++ b/app/parsers/date_parser.rb
@@ -9,7 +9,9 @@ def parse
       DateStringParser.new(date_param).parse
     when Hash
       DateHashParser.new(date_param).parse
-    else raise ArgumentError, "date_param must be a String or a Hash"
+    when nil
+      nil
+    else raise ArgumentError, "date_param must be a String, Hash, or nil"
     end
   end
 
diff --git a/spec/parsers/date_parser_spec.rb b/spec/parsers/date_parser_spec.rb
index 54ec41345..0339f0440 100644
--- a/spec/parsers/date_parser_spec.rb
+++ b/spec/parsers/date_parser_spec.rb
@@ -19,5 +19,21 @@
         expect(date_parser.parse).to eq(Date.new(2024, 8, 17))
       end
     end
+
+    context "when given nil" do
+      let(:date_param) { nil }
+
+      it "returns nil" do
+        expect(date_parser.parse).to be_nil
+      end
+    end
+
+    context "when given an unexpected object" do
+      let(:date_param) { Object.new }
+
+      it "raises an error" do
+        expect { date_parser.parse }.to raise_error(ArgumentError, /be a String, Hash, or nil/)
+      end
+    end
   end
 end