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//! What:
//! The fixture root that the controls of the btrfs primitives and of the subvolume migration need, and the loud
//! report where there is none.
//! Why:
//! The real btrfs ioctls need a btrfs filesystem under the fixture root. The container gate runs on an overlay, where
//! they cannot run. A control that silently passed there would claim coverage it does not have, so a control that
//! needs btrfs fails with the reason unless the run states that the absence is known (the variable below, which the
//! gate image sets); with the variable it prints one line per control that did not run, naming the control.
//!
//! In TS you'd write (pseudocode):
//! ```ts
//! const root = await btrfsFixture(name); // throws unless the run acknowledged that btrfs is absent
//! ```
use super::fs_kind::{FilesystemKind, filesystem_kind};
use crate::test_support::fixture;
use std::path::PathBuf;
/// The environment variable that acknowledges "this run has no btrfs fixture root". The container gate image sets it.
pub(crate) const ABSENT_ACKNOWLEDGED_VARIABLE: &str = "CLI_GIT_BTRFS_ABSENT_ACKNOWLEDGED";
/// What:
/// A fresh fixture directory on btrfs, or `None` after reporting that the control did not run.
/// `Option<PathBuf>` is the owned path or nothing.
/// Why:
/// `None` is only returned when the run acknowledged that btrfs is absent; otherwise the call panics with the
/// filesystem it found and the two ways forward (point `CLI_GIT_TEST_ROOT` at a btrfs directory, or acknowledge).
///
/// In TS you'd write (pseudocode):
/// ```ts
/// function btrfsFixture(name: string): string | undefined;
/// ```
pub(crate) fn btrfs_fixture(name: &str) -> Option<PathBuf> {
let root: PathBuf = fixture(name);
let kind: Result<FilesystemKind, _> = filesystem_kind(root.as_path());
if kind == Ok(FilesystemKind::Btrfs) {
return Some(root);
}
let acknowledged: bool = std::env::var_os(ABSENT_ACKNOWLEDGED_VARIABLE).is_some_and(|value| { return !value.is_empty(); });
assert!(
acknowledged,
"the control {name} needs a btrfs fixture root, but {} is on {kind:?}; set CLI_GIT_TEST_ROOT to a directory on \
btrfs, or set {ABSENT_ACKNOWLEDGED_VARIABLE}=1 to state that this run has none",
root.display()
);
eprintln!("BTRFS CONTROL NOT RUN: {name} (fixture root {} is on {kind:?}; the host task native:test:host covers it)", root.display());
return None;
}
/// What:
/// The same, plus the information whether the mount allows an unprivileged subvolume removal.
/// Why:
/// Controls that destroy a subvolume with the ioctl have two correct outcomes, by the mount option.
///
/// In TS you'd write (pseudocode):
/// ```ts
/// const removalAllowed = (await readMountFacts(root))?.hasOption('user_subvol_rm_allowed');
/// ```
pub(crate) fn removal_allowed(root: &std::path::Path) -> bool {
return super::fs_mount_options::read_mount_facts(root)
.ok()
.flatten()
.is_some_and(|facts| { return facts.has_option("user_subvol_rm_allowed"); });
}