Hot fix merge config (#1507)

## Why make this change?

- To include the fix for the issue with merge config issue.
#1493
- Also include the fix for broken schema links/path in test configs

## What is this change?
- cherry-picking fix for bugs found in 0.7

---------

Co-authored-by: Shyam Sundar J  <shyamsundarj@microsoft.com>

Author: abhishekkumams

src/Cli.Tests/UtilsTests.cs

@@ -222,7 +222,7 @@ public void TestMergeConfig()
             Environment.SetEnvironmentVariable(RUNTIME_ENVIRONMENT_VAR_NAME, "Test");
             File.WriteAllText("dab-config.json", BASE_CONFIG);
             File.WriteAllText("dab-config.Test.json", ENV_BASED_CONFIG);
-            if (TryMergeConfigsIfAvailable(out string mergedConfig))
+            if (TryMergeConfigsIfAvailable(out string? mergedConfig))
             {
                 Assert.AreEqual(mergedConfig, "dab-config.Test.merged.json");
                 Assert.IsTrue(File.Exists(mergedConfig));
@@ -234,6 +234,69 @@ public void TestMergeConfig()
             }
         }
 
+        /// <summary>
+        /// Test to verify that merged config file is only used for the below scenario
+        /// 1. Environment value is set.
+        /// 2. Both Base and envBased config file is present.
+        /// In all other cases, the TryMergeConfigsIfAvailable method should return false
+        /// and out param for the mergedConfigFile should be null.
+        /// </summary>
+        [DataTestMethod]
+        [DataRow("", false, false, null, false, DisplayName = "If environment value is not set, merged config file is not generated.")]
+        [DataRow("", false, true, null, false, DisplayName = "If environment value is not set, merged config file is not generated.")]
+        [DataRow("", true, false, null, false, DisplayName = "If environment value is not set, merged config file is not generated.")]
+        [DataRow("", true, true, null, false, DisplayName = "If environment value is not set, merged config file is not generated.")]
+        [DataRow(null, false, false, null, false, DisplayName = "If environment variable is removed, merged config file is not generated.")]
+        [DataRow(null, false, true, null, false, DisplayName = "If environment variable is removed, merged config file is not generated.")]
+        [DataRow(null, true, false, null, false, DisplayName = "If environment variable is removed, merged config file is not generated.")]
+        [DataRow(null, true, true, null, false, DisplayName = "If environment variable is removed, merged config file is not generated.")]
+        [DataRow("Test", false, false, null, false, DisplayName = "Environment value set but base config not available, merged config file is not generated.")]
+        [DataRow("Test", false, true, null, false, DisplayName = "Environment value set but base config not available, merged config file is not generated.")]
+        [DataRow("Test", true, false, null, false, DisplayName = "Environment value set but env based config not available, merged config file is not generated.")]
+        [DataRow("Test", true, true, "dab-config.Test.merged.json", true, DisplayName = "Environment value set and both base and envConfig available, merged config file is generated.")]
+        public void TestMergeConfigAvailability(
+            string? environmentValue,
+            bool isBaseConfigPresent,
+            bool isEnvironmentBasedConfigPresent,
+            string? expectedMergedConfigFileName,
+            bool expectedIsMergedConfigAvailable)
+        {
+            // Setting up the test scenarios
+            Environment.SetEnvironmentVariable(RUNTIME_ENVIRONMENT_VAR_NAME, environmentValue);
+            string baseConfig = "dab-config.json";
+            string envBasedConfig = "dab-config.Test.json";
+            if (File.Exists(baseConfig))
+            {
+                File.Delete(baseConfig);
+            }
+
+            if (File.Exists(envBasedConfig))
+            {
+                File.Delete(envBasedConfig);
+            }
+
+            if (isBaseConfigPresent)
+            {
+                if (!File.Exists(baseConfig))
+                {
+                    File.Create(baseConfig).Close();
+                    File.WriteAllText(baseConfig, "{}");
+                }
+            }
+
+            if (isEnvironmentBasedConfigPresent)
+            {
+                if (!File.Exists(envBasedConfig))
+                {
+                    File.Create(envBasedConfig).Close();
+                    File.WriteAllText(envBasedConfig, "{}");
+                }
+            }
+
+            Assert.AreEqual(expectedIsMergedConfigAvailable, TryMergeConfigsIfAvailable(out string? mergedConfigFile));
+            Assert.AreEqual(expectedMergedConfigFileName, mergedConfigFile);
+        }
+
         [ClassCleanup]
         public static void Cleanup()
         {

src/Cli/Utils.cs

@@ -889,31 +889,35 @@ public static bool WriteJsonContentToFile(string file, string jsonContent)
         /// If yes, it will try to merge dab-config.json with dab-config.{DAB_ENVIRONMENT}.json
         /// and create a merged file called dab-config.{DAB_ENVIRONMENT}.merged.json
         /// </summary>
-        /// <returns>Returns the name of the merged Config if successful.</returns>
-        public static bool TryMergeConfigsIfAvailable(out string mergedConfigFile)
+        /// <returns>Returns the name of the merged config if successful.</returns>
+        public static bool TryMergeConfigsIfAvailable([NotNullWhen(true)] out string? mergedConfigFile)
         {
             string? environmentValue = Environment.GetEnvironmentVariable(RUNTIME_ENVIRONMENT_VAR_NAME);
-            mergedConfigFile = string.Empty;
+            mergedConfigFile = null;
             if (!string.IsNullOrEmpty(environmentValue))
             {
                 string baseConfigFile = RuntimeConfigPath.DefaultName;
                 string environmentBasedConfigFile = RuntimeConfigPath.GetFileName(environmentValue, considerOverrides: false);
-                mergedConfigFile = RuntimeConfigPath.GetMergedFileNameForEnvironment(CONFIGFILE_NAME, environmentValue);
 
                 if (DoesFileExistInCurrentDirectory(baseConfigFile) && !string.IsNullOrEmpty(environmentBasedConfigFile))
                 {
                     try
                     {
                         string baseConfigJson = File.ReadAllText(baseConfigFile);
                         string overrideConfigJson = File.ReadAllText(environmentBasedConfigFile);
+                        string currentDir = Directory.GetCurrentDirectory();
+                        _logger.LogInformation($"Merging {Path.Combine(currentDir, baseConfigFile)}"
+                            + $" and {Path.Combine(currentDir, environmentBasedConfigFile)}");
                         string mergedConfigJson = Merge(baseConfigJson, overrideConfigJson);
-
+                        mergedConfigFile = RuntimeConfigPath.GetMergedFileNameForEnvironment(CONFIGFILE_NAME, environmentValue);
                         File.WriteAllText(mergedConfigFile, mergedConfigJson);
+                        _logger.LogInformation($"Generated merged config file: {Path.Combine(currentDir, mergedConfigFile)}");
                         return true;
                     }
                     catch (Exception ex)
                     {
                         _logger.LogError(ex, $"Failed to merge the config files.");
+                        mergedConfigFile = null;
                         return false;
                     }
                 }

src/Service.Tests/dab-config.MsSql.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "https://dataapibuilder.azureedge.net/schemas/vmajor.minor.patch-beta/dab.draft.schema.json",
+  "$schema": "../../schemas/dab.draft.schema.json",
   "data-source": {
     "database-type": "mssql",
     "options": {

src/Service.Tests/dab-config.MySql.json

@@ -1,5 +1,5 @@
 {
-  "$schema": "../../../schemas/dab.draft.schema.json",
+  "$schema": "../../schemas/dab.draft.schema.json",
   "data-source": {
     "database-type": "mysql",
     "connection-string": "server=localhost;database=dab;Allow User Variables=true;uid=root;pwd=REPLACEME"