From a7007589df5cef0b4a80f6e43d24ca47ee6f6015 Mon Sep 17 00:00:00 2001
From: Garry Hill <garry@electric-sql.com>
Date: Tue, 7 Nov 2023 11:36:14 +0000
Subject: [PATCH] fix(electric): CaseClauseError in
 Proxy.Prisma.parse_bind_array() (#632)

---
 .changeset/light-rivers-invite.md             |  5 ++++
 .../lib/electric/postgres/proxy/prisma.ex     | 23 +++++++-------
 .../electric/postgres/proxy/prisma_test.exs   | 30 +++++++++++++++----
 ...introspection_generates_correct_schema.lux | 13 +++++++-
 4 files changed, 54 insertions(+), 17 deletions(-)
 create mode 100644 .changeset/light-rivers-invite.md

diff --git a/.changeset/light-rivers-invite.md b/.changeset/light-rivers-invite.md
new file mode 100644
index 0000000000..86f82ad11d
--- /dev/null
+++ b/.changeset/light-rivers-invite.md
@@ -0,0 +1,5 @@
+---
+"@core/electric": patch
+---
+
+[VAX-1319] Fix CaseClauseError in Proxy.Prisma.parse_bind_array()
diff --git a/components/electric/lib/electric/postgres/proxy/prisma.ex b/components/electric/lib/electric/postgres/proxy/prisma.ex
index 3e80d7448f..35aa237d48 100644
--- a/components/electric/lib/electric/postgres/proxy/prisma.ex
+++ b/components/electric/lib/electric/postgres/proxy/prisma.ex
@@ -91,19 +91,22 @@ defmodule Electric.Postgres.Proxy.Prisma do
   # >>
   def parse_bind_array(encoded_array) do
     case encoded_array do
-      <<
-        1::i32(),
-        0::i32(),
-        19::i32(),
-        1::i32(),
-        1::i32(),
-        len::i32(),
-        value::binary-size(len)
-      >> ->
-        [value]
+      <<1::i32(), 0::i32(), 19::i32(), 0::i32(), _::i32()>> ->
+        []
+
+      <<1::i32(), 0::i32(), 19::i32(), n::i32(), 1::i32(), rest::binary>> ->
+        decode_array_values(rest, n, [])
     end
   end
 
+  defp decode_array_values(<<>>, 0, acc) do
+    Enum.reverse(acc)
+  end
+
+  defp decode_array_values(<<len::i32(), value::binary-size(len), rest::binary>>, n, acc) do
+    decode_array_values(rest, n - 1, [value | acc])
+  end
+
   def injector(config, opts \\ []) do
     capture = {Injector.Prisma, config: config}
 
diff --git a/components/electric/test/electric/postgres/proxy/prisma_test.exs b/components/electric/test/electric/postgres/proxy/prisma_test.exs
index e55d7d6a4c..7b689007b8 100644
--- a/components/electric/test/electric/postgres/proxy/prisma_test.exs
+++ b/components/electric/test/electric/postgres/proxy/prisma_test.exs
@@ -460,12 +460,30 @@ defmodule Electric.Postgres.Proxy.PrismaTest do
     end
   end
 
-  test "parse_bind_array/1" do
-    assert ["public"] =
-             Prisma.parse_bind_array(
-               <<0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 19, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 6, 112,
-                 117, 98, 108, 105, 99>>
-             )
+  describe "parse_bind_array/1" do
+    test "parses a single item array" do
+      assert ["public"] =
+               Prisma.parse_bind_array(
+                 <<0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 19, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 6, 112,
+                   117, 98, 108, 105, 99>>
+               )
+    end
+
+    test "parses a multi-element array" do
+      assert ["public", "private", "blue"] =
+               Prisma.parse_bind_array(
+                 <<0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 19, 0, 0, 0, 3, 0, 0, 0, 1, 0, 0, 0, 6, 112,
+                   117, 98, 108, 105, 99, 0, 0, 0, 7, 112, 114, 105, 118, 97, 116, 101, 0, 0, 0,
+                   4, 98, 108, 117, 101>>
+               )
+    end
+
+    test "parses empty array" do
+      assert [] =
+               Prisma.parse_bind_array(
+                 <<0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 19, 0, 0, 0, 0, 0, 0, 0, 1>>
+               )
+    end
   end
 
   describe "injector" do
diff --git a/e2e/tests/04.02_prisma_introspection_generates_correct_schema.lux b/e2e/tests/04.02_prisma_introspection_generates_correct_schema.lux
index b8cf76b137..ecd0018984 100644
--- a/e2e/tests/04.02_prisma_introspection_generates_correct_schema.lux
+++ b/e2e/tests/04.02_prisma_introspection_generates_correct_schema.lux
@@ -3,6 +3,17 @@
 
 [invoke setup]
 
+[newshell developer]
+    !docker ps
+    ?SH-PROMPT:
+    !mkdir -p ../prisma_example/prisma/
+    ?SH-PROMPT:
+    !cp ../prisma_example/schema.prisma ../prisma_example/prisma/
+    ?SH-PROMPT:
+    !make docker-prisma ARGS='prisma_example_1 prisma db pull'
+    ?The introspected database was empty
+    ?SH-PROMPT:
+
 [global migration_version_1=20230504114018]
 
 [shell proxy_1]
@@ -86,7 +97,7 @@
     ?? [info] Applying migration $migration_version_2
 
 
-[newshell developer]
+[shell developer]
     !docker ps
     ?SH-PROMPT:
     !mkdir -p ../prisma_example/prisma/