fix: incorrect recursive calls when escaping labels' values

[hauleth]

Closes #29

Co-authored-by: Stanislav Muzhyk [email protected]

[hauleth]

cc @abc3 @chasers

[rkallos]

Nice!

I wrote up a regression test, but I'm not sure how to add it to the PR: I don't think I can commit and push to your fork.

diff --git a/test/prometheus_test.exs b/test/prometheus_test.exs
index f384257..f0c6f66 100644
--- a/test/prometheus_test.exs
+++ b/test/prometheus_test.exs
@@ -364,6 +364,38 @@ defmodule PrometheusTest do
 
       assert export(name) == lines_to_string(expected)
     end
+
+    test "#{impl} - regression: label escaping" do
+      name = StorageCounter.fresh_id()
+
+      counter =
+        Metrics.counter(
+          "prometheus.test.counter",
+          description: "a counter"
+        )
+
+      opts = [
+        name: name,
+        metrics: [counter],
+        storage: unquote(impl)
+      ]
+
+      {:ok, _pid} = Peep.start_link(opts)
+
+      Peep.insert_metric(name, counter, 1, %{atom: "\"string\""})
+      Peep.insert_metric(name, counter, 1, %{"\"string\"" => :atom})
+      Peep.insert_metric(name, counter, 1, %{"\"string\"" => "\"string\""})
+
+      expected = [
+        "# HELP prometheus_test_counter a counter",
+        "# TYPE prometheus_test_counter counter",
+        ~s(prometheus_test_counter{atom="\\\"string\\\""} 1),
+        ~s(prometheus_test_counter{\"string\"="atom"} 1),
+        ~s(prometheus_test_counter{\"string\"="\\\"string\\\""} 1)
+      ]
+
+      assert export(name) == lines_to_string(expected)
+    end
   end
 
   defp export(name) do

[hauleth]

I will apply it tomorrow

[hauleth]

Applied

[rkallos]

Thank you! <3