--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/rhg/src/commands/debugignorerhg.rs	Mon Nov 29 14:07:47 2021 +0000
@@ -0,0 +1,40 @@
+use crate::error::CommandError;
+use clap::SubCommand;
+use hg;
+use hg::matchers::get_ignore_matcher;
+use hg::StatusError;
+use log::warn;
+
+pub const HELP_TEXT: &str = "
+Show effective hgignore patterns used by rhg.
+
+This is a pure Rust version of `hg debugignore`.
+
+Some options might be missing, check the list below.
+";
+
+pub fn args() -> clap::App<'static, 'static> {
+    SubCommand::with_name("debugignorerhg").about(HELP_TEXT)
+}
+
+pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {
+    let repo = invocation.repo?;
+
+    let ignore_file = repo.working_directory_vfs().join(".hgignore"); // TODO hardcoded
+
+    let (ignore_matcher, warnings) = get_ignore_matcher(
+        vec![ignore_file],
+        &repo.working_directory_path().to_owned(),
+        &mut |_pattern_bytes| (),
+    )
+    .map_err(|e| StatusError::from(e))?;
+
+    if !warnings.is_empty() {
+        warn!("Pattern warnings: {:?}", &warnings);
+    }
+
+    let patterns = ignore_matcher.debug_get_patterns();
+    invocation.ui.write_stdout(patterns)?;
+    invocation.ui.write_stdout(b"\n")?;
+    Ok(())
+}