Fix unique_constraint support (en-US errors)

.github/workflows/elixir.yml

@@ -24,40 +24,25 @@ jobs:
       matrix:
         mssql:
           - version: "mssql/server:2017-latest"
-          - version:  "mssql/server:2022-latest"
+          - version: "mssql/server:2025-latest"
           - version: "azure-sql-edge:latest"
         pair:
           - otp: 24.3
             elixir: 1.14.3
         include:
           - mssql:
-              version: "mssql/server:2022-latest"
+              version: "mssql/server:2025-latest"
             pair:
               otp: 25.3
               elixir: 1.18.4
             lint: lint
-          - mssql:
-              version: "mssql/server:2022-latest"
-            pair:
-              otp: 24.3
-              elixir: 1.14.3
-            lint: skip_lint
 
     env:
       ACCEPT_EULA: Y
       MIX_ENV: test
       GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
-      - name: Install MSSql Client Tools
-        run: |
-          curl -sSL https://packages.microsoft.com/keys/microsoft.asc \
-            | sudo gpg --dearmor --yes -o /usr/share/keyrings/microsoft-prod.gpg
-          echo "deb [arch=amd64,arm64,armhf signed-by=/usr/share/keyrings/microsoft-prod.gpg] https://packages.microsoft.com/ubuntu/22.04/prod jammy main" \
-            | sudo tee /etc/apt/sources.list.d/mssql-release.list
-          sudo apt-get update
-          sudo apt-get install mssql-tools18 unixodbc-dev
-
       - uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871  # v4.2.1
 
       - name: Setup elixir
@@ -90,6 +75,4 @@ jobs:
         if: ${{ matrix.lint == 'lint' }}
 
       - name: Run Tests
-        run: |
-          export PATH=/opt/mssql-tools18/bin:$PATH
-          mix test
+        run: mix test

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v2.4.0 (2026-08-19)
+### Fixes
+* Fix `unique_constraint` support in Ecto for en-US error messages: MSSQL error metadata is now preserved when re-raising from `query!/4`, `prepare!/3`, `execute!/4` and `close!/2` (#173)
+* Fix connection process crash when the server responds with an error to `sp_unprepare`, e.g. calling `close!/2` on an already closed statement
+
 ## v2.3.8 (2026-05-18)
 ### Improvements
 * Relax decimal dependency

lib/tds.ex

@@ -82,7 +82,6 @@ defmodule Tds do
 
     case DBConnection.prepare_execute(conn, query, params, opts) do
       {:ok, _query, result} -> result
-      {:error, %{mssql: %{msg_text: msg}}} -> raise Tds.Error, msg
       {:error, err} -> raise err
     end
   end
@@ -125,7 +124,6 @@ defmodule Tds do
 
     case DBConnection.prepare(conn, query, opts) do
       {:ok, query} -> query
-      {:error, %{mssql: %{msg_text: msg}}} -> raise Tds.Error, msg
       {:error, err} -> raise err
     end
   end
@@ -145,7 +143,6 @@ defmodule Tds do
   def execute!(conn, query, params, opts \\ []) do
     case DBConnection.execute(conn, query, params, opts) do
       {:ok, _q, result} -> result
-      {:error, %{mssql: %{msg_text: msg}}} -> raise Tds.Error, msg
       {:error, err} -> raise err
     end
   end
@@ -162,7 +159,6 @@ defmodule Tds do
   def close!(conn, query, opts \\ []) do
     case DBConnection.close(conn, query, opts) do
       {:ok, result} -> result
-      {:error, %{mssql: %{msg_text: msg}}} -> raise Tds.Error, msg
       {:error, err} -> raise err
     end
   end

lib/tds/errors.csv

@@ -1,4 +1,4 @@
-unique,2627,Violation of UNIQUE KEY constraint '%.*ls'\..*
+unique,2627,Violation of UNIQUE KEY constraint '(\S+?)'\..*
 unique,2627,Verletzung der UNIQUE KEY-Einschränkung "(\S+?)"\..*
 unique,2627,Violation de la contrainte UNIQUE KEY « (\S+?) »\..*
 unique,2627,制約 '(\S+?)' の UNIQUE KEY 違反.*

lib/tds/protocol.ex

@@ -222,7 +222,7 @@ defmodule Tds.Protocol do
           | {:error | :disconnect, Exception.t(), new_state :: t()}
   def handle_close(query, opts, s) do
     params = opts[:parameters]
-    send_close(query, params, s)
+    send_close(query, params, %{s | state: :executing})
   end
 
   @spec handle_begin(Keyword.t(), t) ::

mix.exs

@@ -2,7 +2,7 @@ defmodule Tds.Mixfile do
   use Mix.Project
 
   @source_url "https://github.com/elixir-ecto/tds"
-  @version "2.3.8"
+  @version "2.4.0"
 
   def project do
     [

test/error_test.exs

@@ -24,4 +24,22 @@ defmodule ErrorTest do
       raise Tds.Error, profession: "crocodile hunter"
     end
   end
+
+  test "extracts unique constraint name from en-US error 2627" do
+    message =
+      "Violation of UNIQUE KEY constraint 'UQ_users_email'. Details: key violation (key value string = (email=foo@bar.com))."
+
+    assert [unique: "UQ_users_email"] = Tds.Error.get_constraint_violations(2627, message)
+  end
+
+  test "extracts unique index name from en-US error 2601" do
+    message =
+      "Cannot insert duplicate key row in object 'dbo.users' with unique index 'IX_users_email'. The duplicate key value is (foo@bar.com)."
+
+    assert [unique: "IX_users_email"] = Tds.Error.get_constraint_violations(2601, message)
+  end
+
+  test "returns no constraints for unknown error code" do
+    assert [] = Tds.Error.get_constraint_violations(9999, "some error")
+  end
 end

test/query_test.exs

@@ -142,6 +142,123 @@ defmodule QueryTest do
     assert [[1]] = query("SELECT 1", [])
   end
 
+  test "query returns Tds.Error with MSSQL error metadata on unique violation", context do
+    query("DROP TABLE UniqueBangTable", [])
+
+    assert :ok =
+             query(
+               "CREATE TABLE UniqueBangTable (id INT, email NVARCHAR(100), " <>
+                 "CONSTRAINT UQ_UniqueBangTable_email UNIQUE (email))",
+               []
+             )
+
+    assert :ok = query("INSERT INTO UniqueBangTable (id, email) VALUES (1, 'foo@bar.com')", [])
+
+    err = query("INSERT INTO UniqueBangTable (id, email) VALUES (2, 'foo@bar.com')", [])
+    assert %{number: 2627, msg_text: msg} = err.mssql
+    assert msg =~ "UQ_UniqueBangTable_email"
+
+    query("DROP TABLE dbo.UniqueBangTable", [])
+  end
+
+  test "query! re-raises Tds.Error preserving MSSQL error metadata", context do
+    pid = context[:pid]
+
+    query("DROP TABLE UniqueBangTable2", [])
+
+    assert :ok =
+             query(
+               "CREATE TABLE UniqueBangTable2 (id INT, email NVARCHAR(100), " <>
+                 "CONSTRAINT UQ_UniqueBangTable2_email UNIQUE (email))",
+               []
+             )
+
+    assert :ok = query("INSERT INTO UniqueBangTable2 (id, email) VALUES (1, 'foo@bar.com')", [])
+
+    err =
+      try do
+        Tds.query!(pid, "INSERT INTO UniqueBangTable2 (id, email) VALUES (2, 'foo@bar.com')", [])
+        flunk("expected Tds.Error to be raised")
+      rescue
+        e in Tds.Error -> e
+      end
+
+    assert %{number: 2627, msg_text: msg} = err.mssql
+    assert msg =~ "UQ_UniqueBangTable2_email"
+
+    query("DROP TABLE dbo.UniqueBangTable2", [])
+  end
+
+  test "prepare! re-raises Tds.Error preserving MSSQL error metadata", context do
+    pid = context[:pid]
+
+    err =
+      try do
+        Tds.prepare!(pid, "SELECT * FROM UniqueBangPrepareMissingTable", [])
+        flunk("expected Tds.Error to be raised")
+      rescue
+        e in Tds.Error -> e
+      end
+
+    assert %{number: 208, msg_text: msg} = err.mssql
+    assert msg =~ "UniqueBangPrepareMissingTable"
+  end
+
+  test "execute! re-raises Tds.Error preserving MSSQL error metadata on unique violation",
+       context do
+    pid = context[:pid]
+
+    query("DROP TABLE UniqueBangExecuteTable", [])
+
+    assert :ok =
+             query(
+               "CREATE TABLE UniqueBangExecuteTable (id INT, email NVARCHAR(100), " <>
+                 "CONSTRAINT UQ_UniqueBangExecuteTable_email UNIQUE (email))",
+               []
+             )
+
+    assert :ok =
+             query("INSERT INTO UniqueBangExecuteTable (id, email) VALUES (1, 'foo@bar.com')", [])
+
+    {:ok, q} =
+      Tds.prepare(
+        pid,
+        "INSERT INTO UniqueBangExecuteTable (id, email) VALUES (2, 'foo@bar.com')",
+        []
+      )
+
+    err =
+      try do
+        Tds.execute!(pid, q, [], [])
+        flunk("expected Tds.Error to be raised")
+      rescue
+        e in Tds.Error -> e
+      end
+
+    assert %{number: 2627, msg_text: msg} = err.mssql
+    assert msg =~ "UQ_UniqueBangExecuteTable_email"
+
+    query("DROP TABLE dbo.UniqueBangExecuteTable", [])
+  end
+
+  test "close! re-raises Tds.Error preserving MSSQL error metadata", context do
+    pid = context[:pid]
+
+    {:ok, q} = Tds.prepare(pid, "SELECT 1", [])
+    assert %Tds.Result{} = Tds.close!(pid, q, [])
+
+    err =
+      try do
+        Tds.close!(pid, q, [])
+        flunk("expected Tds.Error to be raised")
+      rescue
+        e in Tds.Error -> e
+      end
+
+    assert %{number: 8179, msg_text: msg} = err.mssql
+    assert msg =~ "Could not find prepared statement"
+  end
+
   test "char nulls", context do
     assert [[nil]] = query("SELECT CAST(NULL as nvarchar(255))", [])
   end