Redact tokens, passwords and device codes from credential ToString [patch]

GitIntegration.Test/Hosting/CredentialRedactionTests.cs

@@ -0,0 +1,75 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.GitIntegration.Test;
+
+using System;
+
+[TestClass]
+public sealed class CredentialRedactionTests
+{
+	private const string Secret = "gho_s3cretTokenValue";
+
+	[TestMethod]
+	public void ATokenCredentialDoesNotPrintItsToken()
+	{
+		string printed = HostingCredential.FromToken(Secret).ToString();
+
+		Assert.DoesNotContain(Secret, printed);
+		Assert.AreEqual("HostingCredential { Kind = Token, Token = ***, Username = , Password =  }", printed);
+	}
+
+	[TestMethod]
+	public void ABearerCredentialDoesNotPrintItsToken()
+	{
+		string printed = HostingCredential.FromBearerToken(Secret).ToString();
+
+		Assert.DoesNotContain(Secret, printed);
+		Assert.Contains("Kind = BearerToken", printed);
+	}
+
+	[TestMethod]
+	public void AUsernamePasswordCredentialPrintsTheUsernameButNotThePassword()
+	{
+		HostingCredential credential = new()
+		{
+			Kind = HostingCredentialKind.UsernamePassword,
+			Username = "octocat",
+			Password = Secret,
+		};
+
+		string printed = credential.ToString();
+
+		Assert.DoesNotContain(Secret, printed);
+		Assert.AreEqual("HostingCredential { Kind = UsernamePassword, Token = , Username = octocat, Password = *** }", printed);
+	}
+
+	[TestMethod]
+	public void InterpolatingACredentialDoesNotLeakItsToken()
+	{
+		HostingCredential credential = HostingCredential.FromToken(Secret);
+
+		string message = $"Signed in: {credential}";
+
+		Assert.DoesNotContain(Secret, message);
+	}
+
+	[TestMethod]
+	public void ADeviceCodePrintsTheUserCodeButNotTheDeviceCode()
+	{
+		GitHubDeviceCode code = new()
+		{
+			UserCode = "WXYZ-1234",
+			DeviceCode = Secret,
+			VerificationUri = new Uri("https://github.com/login/device"),
+			ExpiresIn = TimeSpan.FromSeconds(900),
+			Interval = TimeSpan.FromSeconds(5),
+		};
+
+		string printed = code.ToString();
+
+		Assert.DoesNotContain(Secret, printed);
+		Assert.Contains("UserCode = WXYZ-1234", printed);
+		Assert.Contains("DeviceCode = ***", printed);
+		Assert.Contains("VerificationUri = https://github.com/login/device", printed);
+	}
+}

GitIntegration/GitProvider.cs

@@ -585,6 +585,16 @@ public sealed record HostingCredential
 	/// <summary>Gets the password, when <see cref="Kind"/> is <see cref="HostingCredentialKind.UsernamePassword"/>.</summary>
 	public string? Password { get; init; }
 
+	/// <summary>Returns the record's members with <see cref="Token"/> and <see cref="Password"/> redacted.</summary>
+	/// <remarks>
+	/// The compiler-generated version prints every property, so logging or interpolating a
+	/// credential wrote a live token in plain text. A secret prints as <c>***</c> when present and
+	/// blank when absent, which keeps "is one set" visible for diagnostics without the value.
+	/// </remarks>
+	/// <returns>The credential as the compiler would print it, minus the secrets.</returns>
+	public override string ToString() =>
+		$"{nameof(HostingCredential)} {{ Kind = {Kind}, Token = {Redacted.Of(Token)}, Username = {Username}, Password = {Redacted.Of(Password)} }}";
+
 	/// <summary>Creates a result carrying a host-native token, such as a personal access token.</summary>
 	/// <remarks>
 	/// Not a bearer token. Azure DevOps sends this kind as Basic with an empty username, the scheme

GitIntegration/Hosting/GitHubDeviceFlow.cs

@@ -39,6 +39,16 @@ public sealed record GitHubDeviceCode
 
 	/// <summary>Gets the minimum wait GitHub requires between token requests.</summary>
 	public required TimeSpan Interval { get; init; }
+
+	/// <summary>Returns the record's members with <see cref="DeviceCode"/> redacted.</summary>
+	/// <remarks>
+	/// The device code is what the token poll exchanges for a credential, so it is as sensitive as
+	/// the token while it is valid. <see cref="UserCode"/> stays visible: it is shown to the user
+	/// anyway, and it is what a log needs to match a sign-in attempt.
+	/// </remarks>
+	/// <returns>The device code as the compiler would print it, minus the secret.</returns>
+	public override string ToString() =>
+		$"{nameof(GitHubDeviceCode)} {{ UserCode = {UserCode}, DeviceCode = {Redacted.Of(DeviceCode)}, VerificationUri = {VerificationUri}, ExpiresIn = {ExpiresIn}, Interval = {Interval} }}";
 }
 
 /// <summary>

GitIntegration/Hosting/Redacted.cs

@@ -0,0 +1,20 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.GitIntegration;
+
+/// <summary>
+/// The placeholder a record's <c>ToString</c> prints in place of a secret.
+/// </summary>
+internal static class Redacted
+{
+	/// <summary>The text printed for a secret that is present.</summary>
+	internal const string Placeholder = "***";
+
+	/// <summary>
+	/// Returns <see cref="Placeholder"/> for a present secret and an empty string for an absent one,
+	/// matching how a record prints a <see langword="null"/> member.
+	/// </summary>
+	/// <param name="secret">The secret, or <see langword="null"/>.</param>
+	/// <returns>The text to print in the secret's place.</returns>
+	internal static string Of(string? secret) => secret is null ? string.Empty : Placeholder;
+}