improved CoalesceMacro logic

dotnet · Nov 4, 2022 · bd6a24b · bd6a24b
1 parent 16315b5
commit bd6a24b
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Showing 2 changed files with 55 additions and 6 deletions.
diff --git a/src/Microsoft.TemplateEngine.Orchestrator.RunnableProjects/Macros/CoalesceMacro.cs b/src/Microsoft.TemplateEngine.Orchestrator.RunnableProjects/Macros/CoalesceMacro.cs
@@ -19,15 +19,34 @@ public override void Evaluate(IEngineEnvironmentSettings environmentSettings, IV
         {
             if (variableCollection.TryGetValue(config.SourceVariableName, out object currentSourceValue) && currentSourceValue != null)
             {
-                if (config.DefaultValue != null && currentSourceValue.Equals(config.DefaultValue))
+                if (config.DefaultValue != null && currentSourceValue.ToString().Equals(config.DefaultValue))
                 {
                     environmentSettings.Host.Logger.LogDebug("[{macro}]: '{var}': source value '{source}' is not used, because it is equal to default value '{default}'.", nameof(CoalesceMacro), config.VariableName, currentSourceValue, config.DefaultValue);
                 }
                 else
                 {
-                    variableCollection[config.VariableName] = currentSourceValue;
-                    environmentSettings.Host.Logger.LogDebug("[{macro}]: Assigned variable '{var}' to '{value}'.", nameof(CoalesceMacro), config.VariableName, currentSourceValue);
-                    return;
+                    if (currentSourceValue is string str && string.IsNullOrEmpty(str))
+                    {
+                        //do nothing, empty value for string is equivalent to null.
+                        environmentSettings.Host.Logger.LogDebug("[{macro}]: '{var}': source value '{source}' is an empty string, fall back.", nameof(CoalesceMacro), config.VariableName, currentSourceValue);
+                    }
+                    else if (currentSourceValue.GetType().IsValueType && Activator.CreateInstance(currentSourceValue.GetType()).Equals(currentSourceValue))
+                    {
+                        //do nothing, the value is a value type and is a default.
+                        environmentSettings.Host.Logger.LogDebug(
+                            "[{macro}]: '{var}': source value '{source}' of type '{type}' is equivalent to its default value '{default}', fall back.",
+                            nameof(CoalesceMacro),
+                            config.VariableName,
+                            config.SourceVariableName,
+                            currentSourceValue.GetType().Name,
+                            currentSourceValue);
+                    }
+                    else
+                    {
+                        variableCollection[config.VariableName] = currentSourceValue;
+                        environmentSettings.Host.Logger.LogDebug("[{macro}]: Assigned variable '{var}' to '{value}'.", nameof(CoalesceMacro), config.VariableName, currentSourceValue);
+                        return;
+                    }
                 }
             }
             if (variableCollection.TryGetValue(config.FallbackVariableName, out object currentFallbackValue) && currentFallbackValue != null)

diff --git a/...t.TemplateEngine.Orchestrator.RunnableProjects.UnitTests/MacroTests/CoalesceMacroTests.cs b/...t.TemplateEngine.Orchestrator.RunnableProjects.UnitTests/MacroTests/CoalesceMacroTests.cs
@@ -3,6 +3,8 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Extensions.Logging;
 using Microsoft.TemplateEngine.Abstractions;
 using Microsoft.TemplateEngine.Core;
 using Microsoft.TemplateEngine.Orchestrator.RunnableProjects.ConfigModel;
@@ -16,17 +18,19 @@ namespace Microsoft.TemplateEngine.Orchestrator.RunnableProjects.UnitTests.Macro
     public class CoalesceMacroTests : IClassFixture<EnvironmentSettingsHelper>
     {
         private readonly IEngineEnvironmentSettings _engineEnvironmentSettings;
+        private readonly EnvironmentSettingsHelper _environmentSettingsHelper;
 
         public CoalesceMacroTests(EnvironmentSettingsHelper environmentSettingsHelper)
         {
             _engineEnvironmentSettings = environmentSettingsHelper.CreateEnvironment(hostIdentifier: GetType().Name, virtualize: true);
+            _environmentSettingsHelper = environmentSettingsHelper;
         }
 
         [Theory]
         [InlineData(null, null, null, null)]
         [InlineData("", "", null, "")]
         [InlineData(null, "fallback", null, "fallback")]
-        [InlineData("", "fallback", null, "")]
+        [InlineData("", "fallback", null, "fallback")]
         [InlineData("def", "fallback", "def", "fallback")]
         [InlineData("def", "fallback", "", "def")]
         public void CoalesceMacroTest(string? sourceValue, string? fallbackValue, string? defaultValue, string? expectedResult)
@@ -60,7 +64,7 @@ public void CoalesceMacroTest(string? sourceValue, string? fallbackValue, string
         [InlineData(null, null, null, null)]
         [InlineData("", "", null, "")]
         [InlineData(null, "fallback", null, "fallback")]
-        [InlineData("", "fallback", null, "")]
+        [InlineData("", "fallback", null, "fallback")]
         [InlineData("def", "fallback", "def", "fallback")]
         [InlineData("def", "fallback", "", "def")]
         public void GeneratedSymbolTest(string? sourceValue, string? fallbackValue, string? defaultValue, string? expectedResult)
@@ -99,6 +103,32 @@ public void GeneratedSymbolTest(string? sourceValue, string? fallbackValue, stri
             }
         }
 
+        [Fact]
+        public void GeneratedSymbolTest_DefaultValueLeadsToFallback()
+        {
+            List<(LogLevel Level, string Message)> loggedMessages = new();
+            InMemoryLoggerProvider loggerProvider = new(loggedMessages);
+            IEngineEnvironmentSettings environmentSettings = _environmentSettingsHelper.CreateEnvironment(virtualize: true, addLoggerProviders: new[] { loggerProvider });
+
+            CoalesceMacro macro = new();
+
+            Dictionary<string, string> jsonParameters = new(StringComparer.OrdinalIgnoreCase)
+            {
+                { "sourceVariableName", JExtensions.ToJsonString("varA") },
+                { "fallbackVariableName", JExtensions.ToJsonString("varB") }
+            };
+
+            VariableCollection variables = new()
+            {
+                ["varA"] = 0,
+                ["varB"] = 10
+            };
+
+            macro.Evaluate(environmentSettings, variables, new GeneratedSymbol("test", "coalesce", jsonParameters));
+            Assert.Equal(10, variables["test"]);
+            Assert.Equal("[CoalesceMacro]: 'test': source value 'varA' of type 'Int32' is equivalent to its default value '0', fall back.", loggedMessages.First().Message);
+        }
+
         [Fact]
         public void InvalidConfigurationTest_Source()
         {