From 78104b5e82c5149c2f0155cb4d8558000f1cc8cb Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Wed, 13 Mar 2024 20:08:25 +0900
Subject: [PATCH] cli: extract function that stringifies RevsetParseError

---
 cli/src/command_error.rs | 9 ++++-----
 cli/src/revset_util.rs   | 6 ++++++
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/cli/src/command_error.rs b/cli/src/command_error.rs
index 5ac297b25..8fa0af42b 100644
--- a/cli/src/command_error.rs
+++ b/cli/src/command_error.rs
@@ -38,7 +38,7 @@ use thiserror::Error;
 use crate::merge_tools::{
     ConflictResolveError, DiffEditError, DiffGenerateError, MergeToolConfigError,
 };
-use crate::revset_util::UserRevsetEvaluationError;
+use crate::revset_util::{self, UserRevsetEvaluationError};
 use crate::template_parser::{TemplateParseError, TemplateParseErrorKind};
 use crate::ui::Ui;
 
@@ -347,10 +347,9 @@ impl From<RevsetEvaluationError> for CommandError {
 
 impl From<RevsetParseError> for CommandError {
     fn from(err: RevsetParseError) -> Self {
-        let err_chain = iter::successors(Some(&err), |e| e.origin());
-        let message = err_chain.clone().join("\n");
         // Only for the bottom error, which is usually the root cause
-        let hint = match err_chain.last().unwrap().kind() {
+        let bottom_err = iter::successors(Some(&err), |e| e.origin()).last().unwrap();
+        let hint = match bottom_err.kind() {
             RevsetParseErrorKind::NotPrefixOperator {
                 op: _,
                 similar_op,
@@ -372,7 +371,7 @@ impl From<RevsetParseError> for CommandError {
             } => format_similarity_hint(candidates),
             _ => None,
         };
-        user_error_with_hint_opt(format!("Failed to parse revset: {message}"), hint)
+        user_error_with_hint_opt(revset_util::format_parse_error(&err), hint)
     }
 }
 
diff --git a/cli/src/revset_util.rs b/cli/src/revset_util.rs
index e938be40f..0c88c9b49 100644
--- a/cli/src/revset_util.rs
+++ b/cli/src/revset_util.rs
@@ -14,6 +14,7 @@
 
 //! Utility for parsing and evaluating user-provided revset expressions.
 
+use std::iter;
 use std::rc::Rc;
 
 use itertools::Itertools as _;
@@ -135,3 +136,8 @@ pub fn parse_immutable_expression(
             repo.store().root_commit_id().clone(),
         )))
 }
+
+pub fn format_parse_error(err: &RevsetParseError) -> String {
+    let message = iter::successors(Some(err), |e| e.origin()).join("\n");
+    format!("Failed to parse revset: {message}")
+}