From 15cafb35902b8c4cfbc57a4d8ed982ede4ed6183 Mon Sep 17 00:00:00 2001
From: Diggory Blake <diggsey@googlemail.com>
Date: Wed, 13 Oct 2021 16:32:17 +0100
Subject: [PATCH] Fix bug with `mq_latest_message` where the wrong message may
 be returned if multiple messages have the exact same creation date.

---
 Cargo.toml                                    |  4 ++--
 ...11013151757_fix_mq_latest_message.down.sql | 15 +++++++++++++++
 ...0211013151757_fix_mq_latest_message.up.sql | 19 +++++++++++++++++++
 sqlxmq_macros/Cargo.toml                      |  2 +-
 ...11013151757_fix_mq_latest_message.down.sql | 15 +++++++++++++++
 ...0211013151757_fix_mq_latest_message.up.sql | 19 +++++++++++++++++++
 6 files changed, 71 insertions(+), 3 deletions(-)
 create mode 100644 migrations/20211013151757_fix_mq_latest_message.down.sql
 create mode 100644 migrations/20211013151757_fix_mq_latest_message.up.sql
 create mode 100644 sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.down.sql
 create mode 100644 sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.up.sql

diff --git a/Cargo.toml b/Cargo.toml
index 2623231..6740ce3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sqlxmq"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Diggory Blake <diggsey@googlemail.com>"]
 edition = "2018"
 license = "MIT OR Apache-2.0"
@@ -23,7 +23,7 @@ uuid = { version = "0.8.2", features = ["v4"] }
 log = "0.4.14"
 serde_json = "1.0.64"
 serde = "1.0.124"
-sqlxmq_macros = { version = "0.3.1", path = "sqlxmq_macros" }
+sqlxmq_macros = { version = "0.3.2", path = "sqlxmq_macros" }
 anymap2 = "0.13.0"
 
 [features]
diff --git a/migrations/20211013151757_fix_mq_latest_message.down.sql b/migrations/20211013151757_fix_mq_latest_message.down.sql
new file mode 100644
index 0000000..d09bd4a
--- /dev/null
+++ b/migrations/20211013151757_fix_mq_latest_message.down.sql
@@ -0,0 +1,15 @@
+CREATE OR REPLACE FUNCTION mq_latest_message(from_channel_name TEXT, from_channel_args TEXT)
+RETURNS UUID AS $$
+    SELECT COALESCE(
+        (
+            SELECT id FROM mq_msgs
+            WHERE channel_name = from_channel_name
+            AND channel_args = from_channel_args
+            AND after_message_id IS NOT NULL
+            AND id != uuid_nil()
+            ORDER BY created_at DESC, id DESC
+            LIMIT 1
+        ),
+        uuid_nil()
+    )
+$$ LANGUAGE SQL STABLE;
diff --git a/migrations/20211013151757_fix_mq_latest_message.up.sql b/migrations/20211013151757_fix_mq_latest_message.up.sql
new file mode 100644
index 0000000..b987c5e
--- /dev/null
+++ b/migrations/20211013151757_fix_mq_latest_message.up.sql
@@ -0,0 +1,19 @@
+CREATE OR REPLACE FUNCTION mq_latest_message(from_channel_name TEXT, from_channel_args TEXT)
+RETURNS UUID AS $$
+    SELECT COALESCE(
+        (
+            SELECT id FROM mq_msgs
+            WHERE channel_name = from_channel_name
+            AND channel_args = from_channel_args
+            AND after_message_id IS NOT NULL
+            AND id != uuid_nil()
+            AND NOT EXISTS(
+                SELECT * FROM mq_msgs AS mq_msgs2
+                WHERE mq_msgs2.after_message_id = mq_msgs.id
+            )
+            ORDER BY created_at DESC
+            LIMIT 1
+        ),
+        uuid_nil()
+    )
+$$ LANGUAGE SQL STABLE;
\ No newline at end of file
diff --git a/sqlxmq_macros/Cargo.toml b/sqlxmq_macros/Cargo.toml
index f1955c0..6b904e5 100644
--- a/sqlxmq_macros/Cargo.toml
+++ b/sqlxmq_macros/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "sqlxmq_macros"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Diggory Blake <diggsey@googlemail.com>"]
 edition = "2018"
 license = "MIT OR Apache-2.0"
diff --git a/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.down.sql b/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.down.sql
new file mode 100644
index 0000000..d09bd4a
--- /dev/null
+++ b/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.down.sql
@@ -0,0 +1,15 @@
+CREATE OR REPLACE FUNCTION mq_latest_message(from_channel_name TEXT, from_channel_args TEXT)
+RETURNS UUID AS $$
+    SELECT COALESCE(
+        (
+            SELECT id FROM mq_msgs
+            WHERE channel_name = from_channel_name
+            AND channel_args = from_channel_args
+            AND after_message_id IS NOT NULL
+            AND id != uuid_nil()
+            ORDER BY created_at DESC, id DESC
+            LIMIT 1
+        ),
+        uuid_nil()
+    )
+$$ LANGUAGE SQL STABLE;
diff --git a/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.up.sql b/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.up.sql
new file mode 100644
index 0000000..b987c5e
--- /dev/null
+++ b/sqlxmq_stress/migrations/20211013151757_fix_mq_latest_message.up.sql
@@ -0,0 +1,19 @@
+CREATE OR REPLACE FUNCTION mq_latest_message(from_channel_name TEXT, from_channel_args TEXT)
+RETURNS UUID AS $$
+    SELECT COALESCE(
+        (
+            SELECT id FROM mq_msgs
+            WHERE channel_name = from_channel_name
+            AND channel_args = from_channel_args
+            AND after_message_id IS NOT NULL
+            AND id != uuid_nil()
+            AND NOT EXISTS(
+                SELECT * FROM mq_msgs AS mq_msgs2
+                WHERE mq_msgs2.after_message_id = mq_msgs.id
+            )
+            ORDER BY created_at DESC
+            LIMIT 1
+        ),
+        uuid_nil()
+    )
+$$ LANGUAGE SQL STABLE;
\ No newline at end of file