From 8033833e9b44a63ebf811fb9455c55edc41b3438 Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Wed, 13 Sep 2023 20:40:08 +0800
Subject: [PATCH 1/2] [R] Fix method name.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

r-devel think this is an unregistered s3 method.

```
Mismatches for apparent methods not registered:
format:
  function(x, ...)
format.eval.string:
  function(iter, eval_res, eval_err)
See section ‘Registering S3 methods’ in the ‘Writing R Extensions’
manual.
```
---
 R-package/R/callbacks.R | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/R-package/R/callbacks.R b/R-package/R/callbacks.R
index 7265967b2ad9..58c3205b5853 100644
--- a/R-package/R/callbacks.R
+++ b/R-package/R/callbacks.R
@@ -70,7 +70,7 @@ cb.print.evaluation <- function(period = 1, showsd = TRUE) {
         i == env$begin_iteration ||
         i == env$end_iteration) {
       stdev <- if (showsd) env$bst_evaluation_err else NULL
-      msg <- format.eval.string(i, env$bst_evaluation, stdev)
+      msg <- format_eval_string(i, env$bst_evaluation, stdev)
       cat(msg, '\n')
     }
   }
@@ -380,7 +380,9 @@ cb.early.stop <- function(stopping_rounds, maximize = FALSE,
     if ((maximize && score > best_score) ||
         (!maximize && score < best_score)) {
 
-      best_msg <<- format.eval.string(i, env$bst_evaluation, env$bst_evaluation_err)
+      best_msg <<- format_eval_string(
+        i, env$bst_evaluation, env$bst_evaluation_err
+      )
       best_score <<- score
       best_iteration <<- i
       best_ntreelimit <<- best_iteration * env$num_parallel_tree
@@ -754,7 +756,7 @@ xgb.gblinear.history <- function(model, class_index = NULL) {
 #
 
 # Format the evaluation metric string
-format.eval.string <- function(iter, eval_res, eval_err = NULL) {
+format_eval_string <- function(iter, eval_res, eval_err = NULL) {
   if (length(eval_res) == 0)
     stop('no evaluation results')
   enames <- names(eval_res)

From 4b9c7afcc90ff6c7ee82fe76a5fa83e4d0b5f6a2 Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Wed, 13 Sep 2023 21:52:23 +0800
Subject: [PATCH 2/2] convention.

---
 R-package/R/callbacks.R | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/R-package/R/callbacks.R b/R-package/R/callbacks.R
index 58c3205b5853..96bcaef32908 100644
--- a/R-package/R/callbacks.R
+++ b/R-package/R/callbacks.R
@@ -70,7 +70,7 @@ cb.print.evaluation <- function(period = 1, showsd = TRUE) {
         i == env$begin_iteration ||
         i == env$end_iteration) {
       stdev <- if (showsd) env$bst_evaluation_err else NULL
-      msg <- format_eval_string(i, env$bst_evaluation, stdev)
+      msg <- .format_eval_string(i, env$bst_evaluation, stdev)
       cat(msg, '\n')
     }
   }
@@ -380,7 +380,7 @@ cb.early.stop <- function(stopping_rounds, maximize = FALSE,
     if ((maximize && score > best_score) ||
         (!maximize && score < best_score)) {
 
-      best_msg <<- format_eval_string(
+      best_msg <<- .format_eval_string(
         i, env$bst_evaluation, env$bst_evaluation_err
       )
       best_score <<- score
@@ -756,7 +756,7 @@ xgb.gblinear.history <- function(model, class_index = NULL) {
 #
 
 # Format the evaluation metric string
-format_eval_string <- function(iter, eval_res, eval_err = NULL) {
+.format_eval_string <- function(iter, eval_res, eval_err = NULL) {
   if (length(eval_res) == 0)
     stop('no evaluation results')
   enames <- names(eval_res)