pitboard-core 0.15.0

// Whether Claude Code keeps its login in Credential Manager on Windows, as far as anything
// Pitboard can read says (`windows_backend_choice`), and that store as Claude Code keeps it.

use super::pieces::{self, Items};
use super::{paths as claude, slot};
use crate::context::Context;
use crate::host::Administered;
use crate::service::Permit;
use crate::store::{Backend, Cost, Error, RawStore};
use serde_json::Value;

pub(crate) const FORCE: &str = "CLAUDE_CODE_FORCE_WINDOWS_CREDMAN";
const FEATURE: &str = "tengu_windows_credman";

// `<service>/<user>`, as `Bun.secrets` names a generic item.
pub(crate) fn target(ctx: &Context, service: &str) -> String {
    format!("{service}/{}", slot::account_name(ctx))
}

// What a session's `process.env` would hold as a string: settings' values are coerced.
fn is_one(value: &Value) -> bool {
    match value {
        Value::String(text) => text == "1",
        Value::Number(number) => number.as_f64() == Some(1.0),
        _ => false,
    }
}

// The config file Claude Code reads its cached features and its legacy `env` from, as JSON.
fn config(ctx: &Context) -> Option<Value> {
    let text = std::fs::read_to_string(claude::config_file(ctx)).ok()?;
    serde_json::from_str(&text).ok()
}

// The variable's value a session would start with: the highest settings layer that sets it,
// over the config file's `env`, over the environment it was started with. A managed source
// Pitboard cannot read, or managed sources that disagree, may set it to anything over every
// other, so nothing turns the store on.
fn forced(ctx: &Context, config: Option<&Value>) -> Option<String> {
    let settings = crate::settings::env_settings(ctx, FORCE).ok()?;
    let managed: Vec<_> = settings.iter().filter(|set| set.managed).collect();
    if managed
        .iter()
        .any(|set| is_one(&set.value) != is_one(&managed[0].value))
    {
        return None;
    }
    if let Some(set) = settings.first() {
        return is_one(&set.value).then(|| format!("`{FORCE}` is 1 in the env of {}", set.layer));
    }
    let in_config = config
        .and_then(|config| config.get("env")?.as_object())
        .and_then(|env| env.iter().find(|(key, _)| key.eq_ignore_ascii_case(FORCE)));
    if let Some((_, value)) = in_config {
        return is_one(value).then(|| {
            format!(
                "`{FORCE}` is 1 in the env of {}",
                claude::config_file(ctx).display()
            )
        });
    }
    if ctx.credential_manager_forced {
        return Some(format!("`{FORCE}` is 1 in Pitboard's environment"));
    }
    let host = ctx.host();
    let (user, machine) = (
        host.user_environment(FORCE),
        host.machine_environment(FORCE),
    );
    let (value, place) = match (user, machine) {
        (Administered::Set(value), _) => (value, r"HKCU\Environment"),
        (_, Administered::Set(value)) => (
            value,
            r"HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment",
        ),
        _ => return None,
    };
    (value == "1").then(|| format!("`{FORCE}` is 1 in {place}"))
}

// Why Claude Code would keep its login in Credential Manager, in words that follow "while".
pub(crate) fn turned_on(ctx: &Context) -> Option<String> {
    let config = config(ctx);
    forced(ctx, config.as_ref()).or_else(|| {
        let cached = config
            .as_ref()
            .and_then(|config| config.get("cachedGrowthBookFeatures")?.get(FEATURE))
            == Some(&Value::Bool(true));
        cached.then(|| {
            format!(
                "{} caches `{FEATURE}` as on",
                claude::config_file(ctx).display()
            )
        })
    })
}

// Its item, or the manifest `#m` of one kept in pieces.
pub(crate) fn holds(ctx: &Context, service: &str) -> Result<bool, Error> {
    let whole = target(ctx, service);
    for name in [whole.clone(), format!("{whole}#m")] {
        if ctx.host().credential_held(ctx, &name)? {
            return Ok(true);
        }
    }
    Ok(false)
}

// With nothing turning its store on, why Claude Code may still keep its login in Credential
// Manager; None where `.credentials.json` alone is its store.
pub(crate) fn ambiguity(ctx: &Context) -> Option<Error> {
    let service = claude::live_service(ctx);
    let target = target(ctx, &service);
    match holds(ctx, &service) {
        Ok(false) => None,
        // What a person cannot tell either, so the way that loses no login comes first.
        Ok(true) => Some(Error::Unreadable(format!(
            "Credential Manager holds a Claude Code login under `{target}`, and nothing Pitboard \
             reads says whether Claude Code uses that store or .credentials.json. Set `{FORCE}` \
             to `1` in the env of {}: Claude Code then uses Credential Manager too, and a login \
             in .credentials.json stays behind it, where `pitboard stow` keeps it. Removing \
             `{target}`, `{target}#m`, `{target}#p` and `{target}#0` onward from Credential \
             Manager instead deletes the login they hold, which may be the one Claude Code signs \
             in with",
            claude::config_dir(ctx).join("settings.json").display()
        ))),
        Err(Error::Unreadable(why)) => Some(Error::Unreadable(format!(
            "Credential Manager could not say whether it holds a Claude Code login under \
             `{target}` ({why})"
        ))),
        Err(out_of_reach) => Some(out_of_reach),
    }
}

// Claude Code's login in Credential Manager, under `<service>/claude-code-user` and its pieces.
pub(crate) struct Store {
    ctx: Context,
}

impl Store {
    pub(crate) fn of(ctx: &Context) -> Store {
        Store { ctx: ctx.clone() }
    }

    fn items<'a>(&'a self, service: &'a str) -> Of<'a> {
        Of {
            ctx: &self.ctx,
            service,
        }
    }
}

struct Of<'a> {
    ctx: &'a Context,
    service: &'a str,
}

impl Of<'_> {
    fn item(&self, name: &str) -> Result<Box<dyn RawStore>, Error> {
        let account = format!("{}{name}", slot::account_name(self.ctx));
        self.ctx
            .host()
            .foreign_secrets(self.ctx, &account)
            .ok_or_else(|| Error::Unreadable("this system has no Credential Manager".into()))
    }
}

impl Items for Of<'_> {
    fn get(&self, name: &str) -> Result<Option<String>, Error> {
        self.item(name)?.read(self.service)
    }

    fn set(&self, permit: Permit, name: &str, value: &str) -> Result<(), Error> {
        self.item(name)?.write(permit, self.service, value)
    }

    fn delete(&self, permit: Permit, name: &str) -> Result<(), Error> {
        self.item(name)?.delete(permit, self.service)
    }
}

impl RawStore for Store {
    fn kind(&self) -> Backend {
        Backend::CredentialManager
    }

    fn contains(&self, service: &str) -> Result<bool, Error> {
        pieces::holds(&self.items(service))
    }

    fn read(&self, service: &str) -> Result<Option<String>, Error> {
        pieces::read(&self.items(service), &target(&self.ctx, service))
    }

    fn write(&self, permit: Permit, service: &str, contents: &str) -> Result<(), Error> {
        pieces::write(
            &self.items(service),
            permit,
            contents,
            &target(&self.ctx, service),
        )
    }

    fn delete(&self, permit: Permit, service: &str) -> Result<(), Error> {
        pieces::delete(&self.items(service), permit)
    }

    fn cost(&self, _service: &str, contents: &str) -> Option<Cost> {
        Some(Cost {
            needs: contents.len(),
            limit: pieces::MOST_BYTES,
            second_route: false,
        })
    }
}

// A test's own slots: its `CLAUDE_CONFIG_DIR`'s and its private sign-in's, where neither is a
// real login's place.
#[cfg(any(test, feature = "test-support"))]
fn own_slots(ctx: &Context, real: &[std::path::PathBuf]) -> Vec<String> {
    let config = ctx
        .claude_config_dir
        .as_deref()
        .filter(|dir| !dir.is_empty())
        .map(std::path::PathBuf::from);
    config
        .into_iter()
        .chain([crate::switch::enroll::signin_dir(ctx)])
        .filter(|dir| dir.is_absolute())
        .filter(|dir| !real.iter().any(|place| crate::host::lies_in(dir, place)))
        .map(|dir| slot::service_for_dir(&dir.to_string_lossy()))
        .collect()
}

// The places a build for tests refuses: this account's own, and each folder its lasting
// environment names for Claude Code's login, which a test may have been started with.
#[cfg(any(test, feature = "test-support"))]
fn refused_places(own: Vec<std::path::PathBuf>, lasting: &[String]) -> Vec<std::path::PathBuf> {
    let named = lasting
        .iter()
        .filter(|dir| !dir.is_empty())
        .map(std::path::PathBuf::from);
    own.into_iter().chain(named).collect()
}

#[cfg(any(test, feature = "test-support"))]
fn real_places() -> Result<Vec<std::path::PathBuf>, String> {
    let lasting: Vec<String> = ["CLAUDE_CONFIG_DIR", "CLAUDE_SECURESTORAGE_CONFIG_DIR"]
        .into_iter()
        .flat_map(crate::host::lasting_environment)
        .collect();
    Ok(refused_places(
        crate::host::real_login_places(None)?,
        &lasting,
    ))
}

// What a build for tests may address in Credential Manager, which only Windows' host asks.
#[cfg(any(test, feature = "test-support"))]
#[cfg_attr(not(windows), allow(dead_code))]
pub(crate) fn own_slots_for_tests(ctx: &Context) -> Vec<String> {
    match real_places() {
        Ok(real) => own_slots(ctx, &real),
        Err(_) => Vec::new(),
    }
}

// Before every Credential Manager call a build for tests makes.
#[cfg(any(test, feature = "test-support"))]
#[cfg_attr(not(windows), allow(dead_code))]
pub(crate) fn refused_in_a_build_for_tests(ctx: &Context, target: &str) -> Option<String> {
    crate::provider::names::refusal(target, &own_slots_for_tests(ctx))
        .map(|why| format!("{why}; {}", not_own(ctx)))
}

// A test's cleanup: every item Credential Manager lists under `service`, each by name, so no
// piece is left past a gap where Claude Code's own delete stops looking.
#[cfg(all(windows, any(test, feature = "test-support")))]
pub(crate) fn swept(ctx: &Context, service: &str) -> Result<(), String> {
    let filter = format!("{service}/*");
    if let Some(why) = refused_in_a_build_for_tests(ctx, &filter) {
        return Err(why);
    }
    let names = crate::host::windows_credman::names(&filter).map_err(|e| e.to_string())?;
    for name in names {
        if let Some(why) = refused_in_a_build_for_tests(ctx, &name) {
            return Err(why);
        }
        crate::host::windows_credman::delete(&name).map_err(|e| format!("`{name}`: {e}"))?;
    }
    Ok(())
}

// Said with a refusal: which slots a build for tests takes for its own, or why its
// `CLAUDE_CONFIG_DIR`'s is none of them.
#[cfg(any(test, feature = "test-support"))]
#[cfg_attr(not(windows), allow(dead_code))]
pub(crate) fn not_own(ctx: &Context) -> String {
    let real = match real_places() {
        Ok(real) => real,
        Err(why) => return format!("{why}, so no slot is its own"),
    };
    let dir = ctx
        .claude_config_dir
        .as_deref()
        .filter(|dir| !dir.is_empty());
    let held = dir.and_then(|dir| {
        real.iter()
            .find(|place| crate::host::lies_in(std::path::Path::new(dir), place))
    });
    match (dir, held) {
        (Some(dir), Some(place)) => format!(
            "its CLAUDE_CONFIG_DIR {dir} is, holds or lies in {}",
            place.display()
        ),
        _ => format!("its own slots are {}", own_slots(ctx, &real).join(", ")),
    }
}

#[cfg(test)]
#[allow(
    clippy::disallowed_methods,
    reason = "a test sets up its scratch files as a person or a tool would"
)]
mod tests {
    use super::*;
    use crate::context::Environment;
    use crate::host::memory::MemoryHost;
    use crate::host::{Hive, Os};
    use serde_json::json;
    use std::path::{Path, PathBuf};
    use std::sync::Arc;

    struct Scratch {
        ctx: Context,
        memory: Arc<MemoryHost>,
        config: PathBuf,
        _home: tempfile::TempDir,
    }

    impl Scratch {
        fn write(&self, path: &Path, value: &Value) {
            std::fs::write(path, value.to_string()).expect("written");
        }

        fn claude_json(&self) -> PathBuf {
            self.config.join(".claude.json")
        }
    }

    fn windows(extra: &[(&str, &str)]) -> Scratch {
        let home = tempfile::tempdir().expect("a scratch home");
        let profile = home.path().to_string_lossy().into_owned();
        let config = home.path().join(".claude");
        std::fs::create_dir_all(&config).expect("a config folder");
        let config_dir = config.to_string_lossy().into_owned();
        let pitboard = home.path().join("pitboard").to_string_lossy().into_owned();
        let mut pairs = vec![
            ("USERPROFILE", profile.as_str()),
            ("CLAUDE_CONFIG_DIR", config_dir.as_str()),
            ("PITBOARD_HOME", pitboard.as_str()),
        ];
        pairs.extend_from_slice(extra);
        let memory = MemoryHost::new();
        // A machine in memory on Windows turns the store on there; these read every signal.
        memory.sets_user_environment(FORCE, "0");
        let ctx = Context::for_command_line(&Environment::on(Os::Windows, pairs))
            .with_memory_stores(Arc::clone(&memory));
        Scratch {
            ctx,
            memory,
            config,
            _home: home,
        }
    }

    fn on(scratch: &Scratch) -> Option<String> {
        turned_on(&scratch.ctx)
    }

    #[test]
    fn the_variable_turns_the_store_on_only_as_1() {
        assert_eq!(
            on(&windows(&[(FORCE, "1")])).as_deref(),
            Some("`CLAUDE_CODE_FORCE_WINDOWS_CREDMAN` is 1 in Pitboard's environment")
        );
        for value in ["true", "0", "", " 1"] {
            assert_eq!(on(&windows(&[(FORCE, value)])), None, "{value:?}");
        }
        assert_eq!(on(&windows(&[])), None);
    }

    #[test]
    fn hkcu_environment_turns_it_on_for_a_session_started_from_now_on() {
        let scratch = windows(&[]);
        scratch.memory.sets_user_environment(FORCE, "1");
        assert_eq!(
            on(&scratch).as_deref(),
            Some(r"`CLAUDE_CODE_FORCE_WINDOWS_CREDMAN` is 1 in HKCU\Environment")
        );
        scratch.memory.sets_user_environment(FORCE, "0");
        assert_eq!(on(&scratch), None);
    }

    #[test]
    fn the_persons_managed_and_policy_settings_turn_it_on_and_a_projects_do_not() {
        let scratch = windows(&[]);
        let settings = scratch.config.join("settings.json");
        scratch.write(&settings, &json!({"env": {FORCE: "1"}}));
        assert_eq!(
            on(&scratch),
            Some(format!(
                "`{FORCE}` is 1 in the env of {}",
                settings.display()
            ))
        );
        scratch.write(
            &settings,
            &json!({"env": {"claude_code_force_windows_credman": 1}}),
        );
        assert!(on(&scratch).is_some(), "a number is a string to a session");

        let managed = PathBuf::from(r"C:\Program Files\ClaudeCode").join("managed-settings.json");
        scratch
            .memory
            .administers(&managed, &json!({"env": {FORCE: "0"}}).to_string());
        assert_eq!(on(&scratch), None, "managed settings are assigned last");
        scratch
            .memory
            .administers(&managed, &json!({"env": {FORCE: "1"}}).to_string());
        assert_eq!(
            on(&scratch),
            Some(format!(
                "`{FORCE}` is 1 in the env of {}",
                managed.display()
            ))
        );

        let scratch = windows(&[]);
        scratch.memory.sets_policy(
            Hive::Machine,
            r"SOFTWARE\Policies\ClaudeCode",
            "Settings",
            &json!({"env": {FORCE: "1"}}).to_string(),
        );
        assert_eq!(
            on(&scratch),
            Some(format!(
                r"`{FORCE}` is 1 in the env of HKLM\SOFTWARE\Policies\ClaudeCode\Settings"
            ))
        );

        let scratch = windows(&[]);
        let project = scratch.config.parent().expect("the home").join("project");
        std::fs::create_dir_all(project.join(".claude")).expect("a project");
        for file in [
            project.join(".claude").join("settings.json"),
            project.join(".claude").join("settings.local.json"),
            scratch.config.join("settings.local.json"),
        ] {
            scratch.write(&file, &json!({"env": {FORCE: "1"}}));
        }
        assert_eq!(on(&scratch), None);
    }

    // `windows_managed_settings`: the policy in `HKLM` is taken over the folder unless it merges
    // them, and a source Pitboard cannot read may be the one taken.
    #[test]
    fn only_the_managed_source_a_session_takes_turns_it_on() {
        let managed = PathBuf::from(r"C:\Program Files\ClaudeCode").join("managed-settings.json");
        let machine = |scratch: &Scratch, policy: Value| {
            scratch.memory.sets_policy(
                Hive::Machine,
                r"SOFTWARE\Policies\ClaudeCode",
                "Settings",
                &policy.to_string(),
            );
        };
        let scratch = windows(&[]);
        scratch
            .memory
            .administers(&managed, &json!({"env": {FORCE: "1"}}).to_string());
        machine(&scratch, json!({"permissions": {"deny": ["Bash"]}}));
        assert_eq!(on(&scratch), None, "the folder is not taken");

        machine(
            &scratch,
            json!({"managedSourcesBehavior": "merge", "permissions": {}}),
        );
        assert!(on(&scratch).is_some(), "merged, the folder is taken too");
        machine(
            &scratch,
            json!({"managedSourcesBehavior": "merge", "env": {FORCE: "0"}}),
        );
        assert_eq!(on(&scratch), None, "merged sources that disagree");

        machine(&scratch, json!({"managedSourcesBehavior": "merge"}));
        assert!(on(&scratch).is_some(), "no policy in HKLM, so the folder");

        let scratch = windows(&[]);
        scratch
            .memory
            .administers(&managed, &json!({"env": {FORCE: "1"}}).to_string());
        scratch.memory.policy_unreadable(
            Hive::Machine,
            r"SOFTWARE\Policies\ClaudeCode",
            "Settings",
            "access is denied",
        );
        assert_eq!(on(&scratch), None, "HKLM may be the one taken");
        let settings = scratch.config.join("settings.json");
        scratch.write(&settings, &json!({"env": {FORCE: "1"}}));
        assert_eq!(
            on(&scratch),
            None,
            "and it is assigned over the person's own"
        );

        let scratch = windows(&[]);
        scratch.write(
            &scratch.config.join("settings.json"),
            &json!({"env": {FORCE: "1"}}),
        );
        scratch
            .memory
            .administers_unreadably(&managed, "access is denied");
        assert_eq!(on(&scratch), None, "the folder may say otherwise");
    }

    // A session's environment is the machine's, the person's own variables assigned over it.
    #[test]
    fn the_machines_environment_turns_it_on_unless_the_persons_says_otherwise() {
        let scratch = windows(&[]);
        scratch.memory.forgets_user_environment(FORCE);
        scratch.memory.sets_machine_environment(FORCE, "1");
        assert_eq!(
            on(&scratch),
            Some(format!(
                r"`{FORCE}` is 1 in HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Environment"
            ))
        );
        scratch.memory.sets_user_environment(FORCE, "0");
        assert_eq!(on(&scratch), None);
    }

    #[test]
    fn the_config_files_env_counts_below_the_persons_settings() {
        let scratch = windows(&[]);
        scratch.write(&scratch.claude_json(), &json!({"env": {FORCE: "1"}}));
        assert_eq!(
            on(&scratch),
            Some(format!(
                "`{FORCE}` is 1 in the env of {}",
                scratch.claude_json().display()
            ))
        );
        scratch.write(
            &scratch.config.join("settings.json"),
            &json!({"env": {FORCE: "0"}}),
        );
        assert_eq!(on(&scratch), None);
        let scratch = windows(&[(FORCE, "1")]);
        scratch.write(&scratch.claude_json(), &json!({"env": {FORCE: "0"}}));
        assert_eq!(on(&scratch), None, "it is assigned over the environment");
    }

    #[test]
    fn the_cached_feature_turns_it_on_from_the_config_file_claude_code_reads() {
        let scratch = windows(&[]);
        let cached =
            |on: Value| json!({"cachedGrowthBookFeatures": {FEATURE: on}, "numStartups": 1});
        scratch.write(&scratch.claude_json(), &cached(json!(true)));
        assert_eq!(
            on(&scratch),
            Some(format!(
                "{} caches `{FEATURE}` as on",
                scratch.claude_json().display()
            ))
        );
        for off in [json!(false), json!("true"), json!(1)] {
            scratch.write(&scratch.claude_json(), &cached(off.clone()));
            assert_eq!(on(&scratch), None, "{off}");
        }
        scratch.write(&scratch.claude_json(), &json!({"numStartups": 1}));
        assert_eq!(on(&scratch), None, "missing");

        let legacy = scratch.config.join(".config.json");
        scratch.write(&scratch.claude_json(), &cached(json!(true)));
        scratch.write(&legacy, &cached(json!(false)));
        assert_eq!(
            on(&scratch),
            None,
            "a non-empty .config.json is the one read"
        );
        std::fs::write(&legacy, "").expect("emptied");
        assert!(on(&scratch).is_some(), "an empty one gives way");
        std::fs::remove_file(&legacy).expect("removed");
        std::fs::create_dir(&legacy).expect("a folder");
        assert!(on(&scratch).is_some(), "so does a folder");
        std::fs::remove_dir(&legacy).expect("removed");
        std::fs::write(&legacy, "{ broken").expect("broken");
        assert_eq!(on(&scratch), None, "a broken one reads as off");
    }

    #[test]
    fn credential_manager_holding_the_live_target_is_ambiguous_with_the_store_off() {
        assert!(ambiguity(&windows(&[]).ctx).is_none());
        for piece in ["", "#m", "#0"] {
            let scratch = windows(&[]);
            let service = claude::live_service(&scratch.ctx);
            scratch
                .memory
                .keeps_credentials(&[&format!("{service}/CLAUDE-CODE-USER{piece}")]);
            let said = ambiguity(&scratch.ctx);
            if piece == "#0" {
                assert!(said.is_none(), "a piece alone is no login");
                continue;
            }
            let Some(Error::Unreadable(said)) = said else {
                panic!("{piece}: refused as unreadable");
            };
            let target = format!("{service}/claude-code-user");
            assert!(
                said.starts_with(&format!(
                    "Credential Manager holds a Claude Code login under `{target}`"
                )),
                "{said}"
            );
            assert!(said.contains("`pitboard stow` keeps it"), "{said}");
            assert!(
                said.contains(&format!(
                    "Removing `{target}`, `{target}#m`, `{target}#p` and `{target}#0` onward \
                     from Credential Manager instead deletes the login they hold"
                )),
                "{said}"
            );
        }
    }

    // The chain is built for this build's own system.
    #[cfg(windows)]
    #[test]
    fn the_chain_is_never_the_file_alone_while_credential_manager_holds_the_live_target() {
        let scratch = windows(&[]);
        let service = claude::live_service(&scratch.ctx);
        let chain = super::super::live::chain(&scratch.ctx);
        assert_eq!(
            crate::store::resolve(&chain, &service).expect("readable"),
            Backend::Absent
        );
        crate::store::write_raw(&chain, Permit::for_a_test(), &service, "{}").expect("written");
        assert_eq!(
            crate::store::resolve(&chain, &service).expect("readable"),
            Backend::File
        );
        scratch
            .memory
            .keeps_credentials(&[&target(&scratch.ctx, &service)]);
        let chain = super::super::live::chain(&scratch.ctx);
        assert!(matches!(
            crate::store::read_raw(&chain, &service),
            Err(Error::Unreadable(_))
        ));
    }

    // A network logon has no credential set (MC-net): out of reach, as every other call there.
    #[test]
    fn a_look_that_fails_refuses_out_of_reach_or_unreadable() {
        let scratch = windows(&[]);
        scratch.memory.credentials_unreachable();
        let refused = ambiguity(&scratch.ctx).expect("refused");
        assert_eq!(refused.code(), "credential_store_locked", "{refused}");

        let scratch = windows(&[]);
        scratch
            .memory
            .credentials_unreadable("Access is denied. (os error 5)");
        let Some(Error::Unreadable(said)) = ambiguity(&scratch.ctx) else {
            panic!("refused as unreadable");
        };
        assert!(
            said.starts_with("Credential Manager could not say whether it holds"),
            "{said}"
        );
        assert!(said.ends_with("(Access is denied. (os error 5))"), "{said}");
    }

    // The chain is built for this build's own system.
    #[cfg(windows)]
    #[test]
    fn out_of_a_network_logons_reach_claude_codes_chain_refuses_as_out_of_reach() {
        let scratch = windows(&[]);
        scratch.memory.credentials_unreachable();
        let service = claude::live_service(&scratch.ctx);
        let chain = super::super::live::chain(&scratch.ctx);
        assert!(matches!(
            crate::store::read_raw(&chain, &service),
            Err(Error::Locked)
        ));
    }

    // The chain is built for this build's own system.
    #[cfg(windows)]
    #[test]
    fn with_the_store_on_claude_codes_chain_is_credential_manager_then_its_file() {
        let scratch = windows(&[(FORCE, "1")]);
        scratch.memory.credentials_unreachable();
        let service = claude::live_service(&scratch.ctx);
        let chain = super::super::live::chain(&scratch.ctx);
        crate::store::write_raw(&chain, Permit::for_a_test(), &service, "{}").expect("written");
        assert_eq!(
            crate::store::resolve(&chain, &service).expect("readable"),
            Backend::CredentialManager
        );
        assert_eq!(scratch.memory.live().peek(&service).as_deref(), Some("{}"));
    }

    // Claude Code's login in this test's own scratch slot, each item taken away by name however
    // the test ends, so the leak check after the run finds none.
    #[cfg(windows)]
    struct Scratched {
        ctx: Context,
        service: String,
        _home: tempfile::TempDir,
    }

    #[cfg(windows)]
    impl Drop for Scratched {
        fn drop(&mut self) {
            if let Err(why) = swept(&self.ctx, &self.service) {
                eprintln!("{} was not swept: {why}", self.service);
            }
        }
    }

    #[cfg(windows)]
    fn scratched() -> Scratched {
        let home = tempfile::tempdir().expect("a scratch home");
        let config = home.path().join(".claude").to_string_lossy().into_owned();
        let ctx = Context::new(home.path().to_path_buf()).with_claude_config_dir(config.clone());
        Scratched {
            service: slot::service_for_dir(&config),
            ctx,
            _home: home,
        }
    }

    #[cfg(windows)]
    #[test]
    fn claude_codes_login_round_trips_through_credential_manager_and_shrinks_back_to_one_item() {
        use pieces::{MANIFEST, MOST_BYTES, PENDING, WHOLE, login, piece, pieces_for};
        let scratch = scratched();
        let (store, permit) = (Store::of(&scratch.ctx), Permit::for_a_test());
        let items = store.items(&scratch.service);
        let there = |name: &str| items.get(name).expect("asked").is_some();
        // 100 pieces: a runner's Credential Manager holds about 237 (ARCHITECTURE.md).
        for bytes in [2399, 2400, 2401, 30_000, 180_000, 2400, 100] {
            let text = login(bytes);
            store
                .write(permit, &scratch.service, &text)
                .unwrap_or_else(|e| panic!("{bytes}: {e}"));
            assert_eq!(
                store.read(&scratch.service).expect("read").as_deref(),
                Some(text.as_str()),
                "{bytes}"
            );
            let n = pieces_for(bytes).expect("it fits");
            assert_eq!(there(WHOLE), n == 0, "{bytes}");
            assert_eq!(there(MANIFEST), n > 0, "{bytes}");
            assert!(!there(PENDING), "{bytes}");
            assert!(!there(&piece(n)), "{bytes}: nothing past the last piece");
            assert!(n == 0 || there(&piece(n - 1)), "{bytes}");
        }
        assert!(matches!(
            store.write(permit, &scratch.service, &login(MOST_BYTES + 1)),
            Err(Error::Write(_))
        ));
        assert_eq!(
            store.read(&scratch.service).expect("read"),
            Some(login(100)),
            "257 pieces write nothing"
        );
    }

    #[cfg(windows)]
    #[test]
    fn a_marker_beside_pieces_reads_unfinished_and_a_bad_manifest_unreadable() {
        use pieces::{MANIFEST, PENDING, login};
        let scratch = scratched();
        let (store, permit) = (Store::of(&scratch.ctx), Permit::for_a_test());
        let items = store.items(&scratch.service);
        store
            .write(permit, &scratch.service, &login(9000))
            .expect("in pieces");
        items.set(permit, PENDING, "4").expect("a marker");
        assert!(matches!(
            store.read(&scratch.service),
            Err(Error::Unfinished(_))
        ));
        items.delete(permit, PENDING).expect("gone");
        items
            .set(permit, MANIFEST, "not a manifest")
            .expect("a bad one");
        assert!(matches!(
            store.read(&scratch.service),
            Err(Error::Unreadable(_))
        ));
    }

    // Pieces replaced in place, the same length: the case Claude Code's own order leaves open.
    #[cfg(windows)]
    #[test]
    fn a_write_to_credential_manager_stopped_after_any_step_leaves_no_login_half_written() {
        use pieces::{claude_code_reads, login};
        let scratch = scratched();
        let (store, permit) = (Store::of(&scratch.ctx), Permit::for_a_test());
        let items = store.items(&scratch.service);
        let (before, after) = (login(5000), login(5000).replace('a', "b"));
        store
            .write(permit, &scratch.service, &before)
            .expect("written");
        let steps = crate::fault::counting("credman.step", || {
            store.write(permit, &scratch.service, &after)
        })
        .1;
        assert!(steps > 4, "{steps}");
        for stop in 1..=steps {
            store
                .write(permit, &scratch.service, &before)
                .expect("written again over whatever was left");
            let _ = crate::fault::killing_nth("credman.step", stop, || {
                store.write(permit, &scratch.service, &after)
            });
            match claude_code_reads(&items) {
                Ok(Some(read)) => assert!(read == before || read == after, "stopped at {stop}"),
                Ok(None) => panic!("stopped at {stop}: signed out"),
                Err(()) => {}
            }
        }
    }

    // A person's `setx CLAUDE_CONFIG_DIR D:\claude` reaches a build for tests started from their
    // shell, and that folder holds a real login wherever it is.
    #[test]
    fn a_folder_the_accounts_lasting_environment_names_is_no_tests_own() {
        let scratch = windows(&[]);
        let config = scratch.config.to_string_lossy().into_owned();
        let own = slot::service_for_dir(&config);
        assert!(own_slots(&scratch.ctx, &refused_places(Vec::new(), &[])).contains(&own));
        let places = refused_places(Vec::new(), &[String::new(), config]);
        assert_eq!(places, std::slice::from_ref(&scratch.config));
        assert!(!own_slots(&scratch.ctx, &places).contains(&own));
    }

    #[test]
    fn a_build_for_tests_looks_only_at_a_tests_own_slots() {
        let scratch = windows(&[]);
        let config = scratch.config.to_string_lossy().into_owned();
        let signin = crate::switch::enroll::signin_dir(&scratch.ctx);
        let own = slot::service_for_dir(&config);
        let signing_in = slot::service_for_dir(&signin.to_string_lossy());
        assert_eq!(own_slots(&scratch.ctx, &[]), [own.clone(), signing_in]);
        assert_eq!(
            own_slots(&scratch.ctx, std::slice::from_ref(&scratch.config)).len(),
            1,
            "a folder that is a real login's place has no slot of a test's"
        );
        let refused =
            |ctx: &Context, name: &str| crate::provider::names::refusal(name, &own_slots(ctx, &[]));
        assert_eq!(
            refused(&scratch.ctx, &format!("{own}/claude-code-user")),
            None
        );
        for piece in ["#m", "#p", "#0", "#255"] {
            assert_eq!(
                refused(&scratch.ctx, &format!("{own}/claude-code-user{piece}")),
                None,
                "{piece}"
            );
        }
        for name in [
            "Claude Code-credentials/claude-code-user".to_owned(),
            "Claude Code-credentials/claude-code-user#0".to_owned(),
            format!(
                "{}/claude-code-user",
                slot::service_for_dir(r"C:\Users\x\.claude")
            ),
            "cli|0123456789abcdef.Codex Auth".to_owned(),
            "secrets|0123456789abcdef.codex".to_owned(),
            "linear|3f2a.Codex MCP Credentials".to_owned(),
        ] {
            assert!(refused(&scratch.ctx, &name).is_some(), "{name}");
        }
        let unset = Context::new(PathBuf::from(r"C:\nowhere"));
        assert!(
            refused(&unset, "Claude Code-credentials/claude-code-user").is_some(),
            "no CLAUDE_CONFIG_DIR is the default item"
        );
        assert_eq!(
            refused_in_a_build_for_tests(&scratch.ctx, &format!("{own}/claude-code-user")),
            None
        );
        assert!(
            refused_in_a_build_for_tests(&scratch.ctx, "Claude Code-credentials/claude-code-user")
                .is_some()
        );
    }
}