From 89980839164ece2bbcb2a8924f7ab6e66311850e Mon Sep 17 00:00:00 2001
From: Alexis Montagne <alexis.montagne@gmail.com>
Date: Tue, 28 Oct 2025 11:42:47 -0700
Subject: [PATCH] stringutil: Handle properly acronyms in the CamelToSnakeCase

---
 stringutil/camel_to_snake_case.go      | 12 ++++++++----
 stringutil/camel_to_snake_case_test.go |  2 ++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/stringutil/camel_to_snake_case.go b/stringutil/camel_to_snake_case.go
index 4787797..d7d5d6a 100644
--- a/stringutil/camel_to_snake_case.go
+++ b/stringutil/camel_to_snake_case.go
@@ -5,11 +5,15 @@ import (
 	"strings"
 )
 
-var upperCase = regexp.MustCompile(`([A-Z]+)`)
+var upperCaseRegexps = []*regexp.Regexp{
+	regexp.MustCompile(`([A-Z][a-z]+)`),
+	regexp.MustCompile(`([A-Z]+)`),
+}
 
 func CamelToSnakeCase(s string) string {
-	s = upperCase.ReplaceAllString(s, `_$1`)
-	s = strings.TrimPrefix(s, "_")
+	for _, re := range upperCaseRegexps {
+		s = re.ReplaceAllStringFunc(s, func(s string) string { return "_" + strings.ToLower(s) })
+	}
 
-	return strings.ToLower(s)
+	return strings.ToLower(strings.TrimPrefix(s, "_"))
 }
diff --git a/stringutil/camel_to_snake_case_test.go b/stringutil/camel_to_snake_case_test.go
index 354531a..88d3ca3 100644
--- a/stringutil/camel_to_snake_case_test.go
+++ b/stringutil/camel_to_snake_case_test.go
@@ -12,6 +12,8 @@ func TestCamelToSnakeCase(t *testing.T) {
 		{"Camel", "camel"},
 		{"VeryVeryLongCamelCase", "very_very_long_camel_case"},
 		{"WithAcronymLikeURL", "with_acronym_like_url"},
+		{"CRMFetcher", "crm_fetcher"},
+		{"A0", "a0"},
 	} {
 		if out := CamelToSnakeCase(tt.in); tt.out != out {
 			t.Errorf("CamelToSnakeCase(%q) = %q wanted: %q", tt.in, out, tt.out)