From 9f514cb1fe939a9b0d2859caa7c050fec38f0c6b Mon Sep 17 00:00:00 2001
From: thiagomajesk <13930952+thiagomajesk@users.noreply.github.com>
Date: Wed, 16 Oct 2024 19:35:42 -0300
Subject: [PATCH 1/2] Handle nil params in get requests

---
 lib/req/steps.ex  | 5 ++---
 test/req_test.exs | 8 ++++++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/req/steps.ex b/lib/req/steps.ex
index 33e332e..cca56e7 100644
--- a/lib/req/steps.ex
+++ b/lib/req/steps.ex
@@ -534,9 +534,8 @@ defmodule Req.Steps do
     put_params(request, Req.Request.get_option(request, :params, []))
   end
 
-  defp put_params(request, []) do
-    request
-  end
+  defp put_params(request, []), do: request
+  defp put_params(request, nil), do: request
 
   defp put_params(request, params) do
     encoded = URI.encode_query(params)
diff --git a/test/req_test.exs b/test/req_test.exs
index b0a3970..90871cf 100644
--- a/test/req_test.exs
+++ b/test/req_test.exs
@@ -95,4 +95,12 @@ defmodule ReqTest do
     resp = Req.get!(origin_url, into: :self)
     assert Req.put!(echo_url, body: resp.body).body == "foobarbaz"
   end
+
+  test "empty params", c do
+    Bypass.expect(c.bypass, "GET", "/", fn conn ->
+      Plug.Conn.send_resp(conn, 200, "")
+    end)
+
+    assert %Req.Response{status: 200} = Req.get!(c.url, params: nil)
+  end
 end

From 1338d4dfbb5c1a4fc22ecf767ef9f96541b9f4cb Mon Sep 17 00:00:00 2001
From: thiagomajesk <13930952+thiagomajesk@users.noreply.github.com>
Date: Thu, 17 Oct 2024 10:42:00 -0300
Subject: [PATCH 2/2] Coalessce nil params and allow unsetting params

---
 lib/req.ex        |  6 ++++++
 lib/req/steps.ex  |  3 +--
 test/req_test.exs | 18 +++++++++++++++++-
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/lib/req.ex b/lib/req.ex
index 2f7d4de..8a0c157 100644
--- a/lib/req.ex
+++ b/lib/req.ex
@@ -544,6 +544,12 @@ defmodule Req do
     update_in(
       request.options,
       &Map.merge(&1, Map.new(options), fn
+        :params, nil, new ->
+          new
+
+        :params, _old, nil ->
+          nil
+
         :params, old, new ->
           Keyword.merge(old, new)
 
diff --git a/lib/req/steps.ex b/lib/req/steps.ex
index cca56e7..8110c5e 100644
--- a/lib/req/steps.ex
+++ b/lib/req/steps.ex
@@ -535,10 +535,9 @@ defmodule Req.Steps do
   end
 
   defp put_params(request, []), do: request
-  defp put_params(request, nil), do: request
 
   defp put_params(request, params) do
-    encoded = URI.encode_query(params)
+    encoded = URI.encode_query(params || [])
 
     update_in(request.url.query, fn
       nil -> encoded
diff --git a/test/req_test.exs b/test/req_test.exs
index 90871cf..aac7c6e 100644
--- a/test/req_test.exs
+++ b/test/req_test.exs
@@ -96,11 +96,27 @@ defmodule ReqTest do
     assert Req.put!(echo_url, body: resp.body).body == "foobarbaz"
   end
 
-  test "empty params", c do
+  test "merge params" do
+    req = Req.new(url: "/", params: [a: 1])
+    assert %{options: %{params: [a: 1, b: 2]}} = Req.merge(req, params: [b: 2])
+  end
+
+  test "merge with empty params" do
+    req = Req.new(url: "/", params: nil)
+    assert %{options: %{params: [a: 1]}} = Req.merge(req, params: [a: 1])
+
+    req = Req.new(url: "/", params: [a: 1])
+    assert %{options: %{params: nil}} = Req.merge(req, params: nil)
+  end
+
+  test "request with empty params", c do
     Bypass.expect(c.bypass, "GET", "/", fn conn ->
       Plug.Conn.send_resp(conn, 200, "")
     end)
 
+
+    assert {:ok, %Req.Response{}} = Req.get(Req.new(url: c.url, params: [a: 1]), params: nil)
+    assert {:ok, %Req.Response{}} = Req.get(Req.new(url: c.url, params: nil), params: [a: 1])
     assert %Req.Response{status: 200} = Req.get!(c.url, params: nil)
   end
 end