From 4625620e6b85d95b38614a4e86f35cc594c66dde Mon Sep 17 00:00:00 2001
From: Vinai Rachakonda <vinai@dolthub.com>
Date: Thu, 30 Sep 2021 16:28:27 -0700
Subject: [PATCH] Add a warning for CREATE DATABASE (#2191)

create database warning
---
 go/libraries/doltcore/sqle/database_provider.go |  5 +++++
 integration-tests/bats/sql-create-database.bats | 10 ++++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/go/libraries/doltcore/sqle/database_provider.go b/go/libraries/doltcore/sqle/database_provider.go
index 66690fd01c..31f9322965 100644
--- a/go/libraries/doltcore/sqle/database_provider.go
+++ b/go/libraries/doltcore/sqle/database_provider.go
@@ -47,6 +47,8 @@ var _ sql.FunctionProvider = DoltDatabaseProvider{}
 var _ sql.MutableDatabaseProvider = DoltDatabaseProvider{}
 var _ dsess.RevisionDatabaseProvider = DoltDatabaseProvider{}
 
+const createDbWC = 1105 // 1105 represents an unknown error.
+
 // NewDoltDatabaseProvider returns a provider for the databases given
 func NewDoltDatabaseProvider(config config.ReadableConfig, databases ...sql.Database) DoltDatabaseProvider {
 	dbs := make(map[string]sql.Database, len(databases))
@@ -128,6 +130,9 @@ func (p DoltDatabaseProvider) CreateDatabase(ctx *sql.Context, name string) erro
 	p.mu.Lock()
 	defer p.mu.Unlock()
 
+	// Throw warning to users that this is a temporary database that does not persist after the session exits.
+	ctx.Warn(createDbWC, "CREATE DATABASE creates an inmemory database that does not persist after the server exits. Dolt currently only supports a single disk backed database created by `dolt init`")
+
 	mem, err := env.NewMemoryDbData(ctx, p.cfg)
 	if err != nil {
 		return err
diff --git a/integration-tests/bats/sql-create-database.bats b/integration-tests/bats/sql-create-database.bats
index c25a7e41c7..7b98a69de3 100644
--- a/integration-tests/bats/sql-create-database.bats
+++ b/integration-tests/bats/sql-create-database.bats
@@ -12,6 +12,7 @@ teardown() {
 @test "sql-create-database: create new database" {
     run dolt sql << SQL
 CREATE DATABASE mydb;
+SHOW WARNINGS;
 SHOW DATABASES;
 USE mydb;
 CREATE TABLE test (
@@ -27,6 +28,8 @@ SQL
     [[ "$output" =~ "mydb" ]] || false
     # From COUNT
     [[ "$output" =~ "1" ]] || false
+    # Validate that CREATE DATABASE throws a warning
+    [[ "$output" =~ 'CREATE DATABASE creates an inmemory database that does not persist after the server exits. Dolt currently only supports a single disk backed database created by `dolt init`' ]] || false
 
     run dolt sql -q "SHOW DATABASES"
     [[ ! "$output" =~ "mydb" ]] || false
@@ -40,7 +43,6 @@ SQL
 
     [ "$status" -eq 1 ]
     [[ "$output" =~ "can't create database mydb; database exists" ]] || false
-
 }
 
 @test "sql-create-database: create database IF NOT EXISTS on database that already exists doesn't throw an error" {
@@ -55,9 +57,13 @@ SQL
 @test "sql-create-database: create and drop new database" {
     run dolt sql << SQL
 CREATE DATABASE mydb;
+SHOW WARNINGS;
 DROP DATABASE mydb;
 USE mydb;
 SQL
+    # Validate that CREATE DATABASE throws a warning
+    [[ "$output" =~ 'CREATE DATABASE creates an inmemory database that does not persist after the server exits. Dolt currently only supports a single disk backed database created by `dolt init`' ]] || false
+
     [ "$status" -eq 1 ]
     [[ "$output" =~ "database not found: mydb" ]] || false
 }
@@ -140,7 +146,7 @@ SQL
     [[ ! "$output" =~ "mydb" ]] || false
 }
 
-@test "sql-create-database: use for non existing datbase throws an error" {
+@test "sql-create-database: use for non existing database throws an error" {
     run dolt sql -q "USE test"
     [ "$status" -eq 1 ]
     [[ "$output" =~ "database not found: test" ]] || false