Add validation when specifying --folder and analyzers

src/FormatCommand.cs

@@ -54,10 +54,30 @@ internal static RootCommand CreateCommandLineOptions()
             };
 
             rootCommand.Description = "dotnet-format";
+            rootCommand.AddValidator(EnsureFolderNotSpecifiedWhenFixingStyle);
+            rootCommand.AddValidator(EnsureFolderNotSpecifiedWhenFixingAnalyzers);
 
             return rootCommand;
         }
 
+        internal static string? EnsureFolderNotSpecifiedWhenFixingAnalyzers(CommandResult symbolResult)
+        {
+            var folder = symbolResult.ValueForOption<bool>("--folder");
+            var fixAnalyzers = symbolResult.OptionResult("--fix-analyzers");
+            return folder && fixAnalyzers != null
+                ? "Cannot specify the '--folder' option when running analyzers."
+                : null;
+        }
+
+        internal static string? EnsureFolderNotSpecifiedWhenFixingStyle(CommandResult symbolResult)
+        {
+            var folder = symbolResult.ValueForOption<bool>("--folder");
+            var fixStyle = symbolResult.OptionResult("--fix-style");
+            return folder && fixStyle != null
+                ? "Cannot specify the '--folder' option when fixing style."
+                : null;
+        }
+
         internal static bool WasOptionUsed(this ParseResult result, params string[] aliases)
         {
             return result.Tokens

tests/ProgramTests.cs

@@ -167,5 +167,31 @@ public void CommandLine_ProjectArgument_FailsIfSpecifiedTwice()
             // Assert
             Assert.Equal(1, result.Errors.Count);
         }
+
+        [Fact]
+        public void CommandLine_FolderValidation_FailsIfFixAnalyzersSpecified()
+        {
+            // Arrange
+            var sut = FormatCommand.CreateCommandLineOptions();
+
+            // Act
+            var result = sut.Parse(new[] { "--folder", "--fix-analyzers" });
+
+            // Assert
+            Assert.Equal(1, result.Errors.Count);
+        }
+
+        [Fact]
+        public void CommandLine_FolderValidation_FailsIfFixStyleSpecified()
+        {
+            // Arrange
+            var sut = FormatCommand.CreateCommandLineOptions();
+
+            // Act
+            var result = sut.Parse(new[] { "--folder", "--fix-style" });
+
+            // Assert
+            Assert.Equal(1, result.Errors.Count);
+        }
     }
 }