From 86ffa2fb231e8f5a8bdbf46c753865006c532518 Mon Sep 17 00:00:00 2001
From: AJ ONeal <aj@therootcompany.com>
Date: Mon, 20 Apr 2026 09:54:04 -0600
Subject: [PATCH] chore: remove IPv6 special-casing (YAGNI)
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Drop the explicit IPv6 early-exit in ReadAll — ParseIPv4 already rejects
non-IPv4 via Is4(). Remove IPv6-specific tests and error message wording.
---
 net/ipcohort/ipcohort.go      |  7 +------
 net/ipcohort/ipcohort_test.go | 24 ------------------------
 2 files changed, 1 insertion(+), 30 deletions(-)

diff --git a/net/ipcohort/ipcohort.go b/net/ipcohort/ipcohort.go
index 4cef8cb..d1e03b5 100644
--- a/net/ipcohort/ipcohort.go
+++ b/net/ipcohort/ipcohort.go
@@ -132,7 +132,7 @@ func ParseIPv4(raw string) (ipv4net IPv4Net, err error) {
 
 	addr := ippre.Addr()
 	if !addr.Is4() {
-		return ipv4net, fmt.Errorf("IPv6 not supported: %s", raw)
+		return ipv4net, fmt.Errorf("not an IPv4 address: %s", raw)
 	}
 	ip4 := addr.As4()
 	prefix := uint8(ippre.Bits()) // 0–32
@@ -203,11 +203,6 @@ func ReadAll(r *csv.Reader) (*Cohort, error) {
 			continue
 		}
 
-		// skip IPv6
-		if strings.Contains(raw, ":") {
-			continue
-		}
-
 		ipv4net, err := ParseIPv4(raw)
 		if err != nil {
 			log.Printf("skipping invalid entry: %q", raw)
diff --git a/net/ipcohort/ipcohort_test.go b/net/ipcohort/ipcohort_test.go
index eb37e35..c5e9d53 100644
--- a/net/ipcohort/ipcohort_test.go
+++ b/net/ipcohort/ipcohort_test.go
@@ -21,7 +21,6 @@ func TestParseIPv4(t *testing.T) {
 		{"", true},
 		{"not-an-ip", true},
 		{"1.2.3.4/33", true},
-		{"::1", true}, // IPv6 not supported
 	}
 	for _, tt := range tests {
 		_, err := ipcohort.ParseIPv4(tt.raw)
@@ -104,16 +103,6 @@ func TestContains_FailClosed(t *testing.T) {
 	}
 }
 
-func TestContains_IPv6NeverBlocked(t *testing.T) {
-	c, _ := ipcohort.Parse([]string{"1.2.3.4", "10.0.0.0/8"})
-	// IPv6 addresses are not stored; should return false, not panic.
-	if c.Contains("::1") {
-		t.Error("IPv6 address should not be in an IPv4-only cohort")
-	}
-	if c.Contains("2001:db8::1") {
-		t.Error("IPv6 address should not be in an IPv4-only cohort")
-	}
-}
 
 func TestContains_Empty(t *testing.T) {
 	c, err := ipcohort.Parse(nil)
@@ -175,16 +164,3 @@ func TestLoadFiles_Merge(t *testing.T) {
 	}
 }
 
-func TestCSVSkipsIPv6(t *testing.T) {
-	dir := t.TempDir()
-	path := filepath.Join(dir, "mixed.txt")
-	os.WriteFile(path, []byte("1.2.3.4\n::1\n2001:db8::/32\n5.6.7.8\n"), 0o644)
-
-	c, err := ipcohort.LoadFile(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if c.Size() != 2 {
-		t.Errorf("Size() = %d, want 2 (IPv6 should be skipped)", c.Size())
-	}
-}