What causes "this launcher does not support patch collection" in Hmbown/CodeWhale?

Use a launcher whose collect_patch is implemented for your platform so the patch can actually be read out.

this launcher does not support patch collection

Error message

this launcher does not support patch collection

What it means

Default SandboxLauncher trait implementation for collect_patch: a launcher that did not override the method reports that it cannot collect the agent's work product (patch) from the sandbox. The default-impl pattern keeps unsupported operations explicit and failing loudly.

Solutions

Use a launcher whose collect_patch is implemented for your platform so the patch can actually be read out.
Check launcher selection: a completed job with this error usually means the wrong backend ran it.
If no patch exists (job never ran), check the job status first instead of calling collect_patch.
Treat this as a terminal environment limitation — re-run the job on a capable launcher to obtain the patch.

Example fix

// before
let patch = launcher.collect_patch(&receipt)?;
// after
let launcher = real_launcher_for_platform();
let patch = launcher.collect_patch(&receipt)?;

Defensive patterns

Strategy: try-catch

Validate before calling

fn launcher_supports_patch(l: &dyn SandboxLauncher) -> bool {
    l.capabilities().contains(Capability::CollectPatch)
}

Try / catch

match launcher.collect_patch(&receipt) {
    Err(e) if e.to_string().contains("does not support patch collection") => {
        eprintln!("no patch available: this launcher cannot collect work products; re-run on a capable launcher");
    }
    other => { /* ... */ }
}

Prevention

Confirm the launcher backend before launching a job whose output you need as a patch.
Check job status/success before attempting patch collection.
Do not wire the default-impl launcher into result-collection flows.
Test the full dispatch->collect path against the real launcher in CI.

When it happens

Trigger: Calling collect_patch on a receipt from a launcher that never implemented patch collection — e.g. after a run in a stubbed environment, or a dispatch flow that finished the harness but selected a launcher without a real collect_patch.

Common situations: Retrieving results of a cloud job run with a fallback/no-op launcher; environments where the sandbox filesystem cannot be read out; wiring mistakes that routed the job to the stub backend.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/f69947b10c37770c. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/cloud_dispatch.rs:1190

/// the full protocol.
pub trait DaytonaLauncher {
    /// Create the sandbox and return its id plus the (validated) toolbox URL.
    fn create_sandbox(&self, job: &CloudJob) -> Result<SandboxReceipt>;
    /// Block until the sandbox accepts toolbox calls (bounded poll).
    fn wait_ready(&self, _receipt: &SandboxReceipt) -> Result<()> {
        Ok(())
    }
    /// Clone the target forge repository inside the sandbox.
    fn clone_repository(&self, _receipt: &SandboxReceipt, _url: &str, _path: &str) -> Result<()> {
        bail!("this launcher does not support repository clones")
    }
    /// Run one harness command inside the sandbox and return bounded stdout.
    fn run_harness(&self, _receipt: &SandboxReceipt, _command: &HarnessCommand) -> Result<String> {
        bail!("this launcher does not support harness execution")
    }
    /// Collect the agent's work product from the sandbox.
    fn collect_patch(&self, _receipt: &SandboxReceipt) -> Result<PatchReceipt> {
        bail!("this launcher does not support patch collection")
    }
    /// Tear the sandbox down. Called on cancel, failure, and completion.
    fn teardown(&self, _receipt: &SandboxReceipt) -> Result<()> {
        bail!("this launcher does not support teardown")
    }
    /// List Codewhale-dispatch sandboxes with their job labels. Used by the
    /// reconciler (startup sweep and cancel); not part of the run protocol.
    fn list_job_sandboxes(&self) -> Result<Vec<LabeledSandbox>> {
        bail!("this launcher does not support sandbox listing")
    }
}

/// One dispatch-labeled sandbox discovered by the reconciler.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct LabeledSandbox {
    pub sandbox_id: String,
    /// Job id from the `codewhale.job` label, when the label is present.
    pub job_id: Option<String>,

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