Is there a way to block a word (or RegEx) from compiling in C#?

Question

I keep all of my project's "secrets" (API keys, database details, etc) outside the application and programmatically access those - both in development and in production. Is there a way, given a list of prohibited strings, I could set up Visual Studio to stop compiling if it sees one of them?

Just really trying not to commit them to the repo (...again).

I reviewed the options in the editorconfig, but that won't do the trick.

Answer 1

1.You can use the pre-build event to call a simple script to check for cs files

2.Custom Roslyn analyzer.

    private static readonly DiagnosticDescriptor Rule = new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Error, isEnabledByDefault: true, description: Description);

    public override void Initialize(AnalysisContext context)
    {
        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
        context.EnableConcurrentExecution();
        context.RegisterSyntaxNodeAction(AnalyzeNode, SyntaxKind.StringLiteralExpression);
    }
    private void AnalyzeNode(SyntaxNodeAnalysisContext context)
    {
        var literalExpression = (LiteralExpressionSyntax)context.Node;
        var literalValue = literalExpression.Token.ValueText;

        // Case insensitive check for "password" substring
        if (literalValue.IndexOf("password", StringComparison.OrdinalIgnoreCase) >= 0)
        {
            var diagnostic = Diagnostic.Create(Rule, literalExpression.GetLocation(), literalValue);
            context.ReportDiagnostic(diagnostic);
        }
    }

Unit Test:

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Threading.Tasks;
using VerifyCS = Analyzer1.Test.CSharpCodeFixVerifier<
    Analyzer1.Analyzer1Analyzer,
    Analyzer1.Analyzer1CodeFixProvider>;

namespace Analyzer1.Test
{
    [TestClass]
    public class Analyzer1UnitTest
    {
        //No diagnostics expected to show up
        [TestMethod]
        public async Task TestMethod1()
        {
            var test = @"
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Diagnostics;

    namespace ConsoleApplication1
    {
        class {|#0:TypeName|}
        {   
public string str=""123password123"";
        }
    }";

            await VerifyCS.VerifyAnalyzerAsync(test);
        }

3. As Jeremy said, use git hook.