Taciturn 0.1.0

Taciturn

A Roslyn incremental source generator for C#: mark a record [Taciturn] and every member is redacted in the compiler's synthesized ToString() — until you explicitly opt one back into the clear with [Plain].

[Taciturn]
public sealed partial record StripeOptions(
    string PublishableKey,
    [property: Plain] string AccountId,
    string WebhookSecret);

Console.WriteLine(new StripeOptions("pk_live_abc123", "acct_1M2n3", "whsec_9f2a"));
// StripeOptions { PublishableKey = «redacted», AccountId = acct_1M2n3, WebhookSecret = «redacted» }

The problem

A record with secret fields — API keys, webhook secrets, connection strings — leaks them the moment someone logs it:

_logger.LogInformation("starting with {Options}", stripeOptions);
// StripeOptions { PublishableKey = pk_live_abc123, WebhookSecret = whsec_9f2a }

Nobody wrote that logging bug. The compiler synthesizes a ToString() that prints every public property, from a one-line type declaration — and it recurs every time someone adds a property to the type, because the whole point of a record's synthesized members is that nobody has to think about them again. Taciturn closes that hole at the type level instead of relying on code review to catch it at every call site, forever.

Install

dotnet add package Taciturn

Mark the type partial and add [Taciturn]:

[Taciturn]
public sealed partial record ApiCredentials(string ClientId, string ClientSecret);

That's it — every member is redacted by default. A property added next month is redacted the day it's added, by nobody, because the redaction is regenerated from the type rather than maintained alongside it.

Opting a member back into the clear

Use [Plain] on the member you want to keep visible. On a positional record parameter, apply it as [property: Plain] — the attribute targets the synthesized property, not the constructor parameter:

[Taciturn]
public sealed partial record ApiCredentials(
    [property: Plain] string ClientId,   // not secret, fine to log
    string ClientSecret);                // stays redacted

Supported shapes

Every C# record shape works, with the signature the compiler actually expects for that shape:

Diagnostics

Debugger view

A [Taciturn] type also gets a generated [DebuggerTypeProxy], so hovering a value in the debugger shows the same redacted/plain split as ToString() — a breakpoint can't bypass what a log line can't.

What this doesn't do

• It never changes what's stored or serialized — only what's printed. A secret is still a live string on the managed heap, and JsonSerializer.Serialize(options) still serializes it in full; Taciturn only closes the ToString()/debugger path.
• No wrapper type (Secret<string>). That closes direct member-access leaks properly, but costs an edit at every call site that reads the value — the whole appeal here is zero call-site changes beyond the attribute.
• No zeroing / SecureString. .NET strings can't be reliably wiped, and SecureString is documented as not recommended for new development.

Building from source

dotnet build
dotnet test
dotnet run --project samples/Taciturn.Sample

License

MIT — see LICENSE.