From b9249233582a8289e9a5252db2c4c005dd787972 Mon Sep 17 00:00:00 2001
From: Vassiliy Yegorov <va@egorovanet.ru>
Date: Mon, 2 Nov 2026 18:01:26 +0700
Subject: [PATCH] fix

---
 internal/provider/selectel/selectel.go | 84 +++++++++++++++++---------
 1 file changed, 54 insertions(+), 30 deletions(-)

diff --git a/internal/provider/selectel/selectel.go b/internal/provider/selectel/selectel.go
index 5717676..0862731 100644
--- a/internal/provider/selectel/selectel.go
+++ b/internal/provider/selectel/selectel.go
@@ -337,40 +337,64 @@ func (c *Client) ApplyChanges(ctx context.Context, creds provider.Credentials, z
 	}
 
 	base := "/zones/" + url.PathEscape(zoneID) + "/rrset"
+	applied := 0
 	for _, d := range cs.Diffs {
 		if d.ReadOnly || d.Kind == diff.InSync {
 			continue
 		}
-		switch d.Kind {
-		case diff.Add:
-			if d.Desired == nil {
-				return fmt.Errorf("selectel: add/update diff without Desired record")
-			}
-			if err := c.do(ctx, http.MethodPost, base, tok, toRRSet(*d.Desired), nil); err != nil {
-				return err
-			}
-		case diff.Update:
-			if d.Desired == nil {
-				return fmt.Errorf("selectel: add/update diff without Desired record")
-			}
-			id, ok := idByKey[d.Desired.Key()]
-			if !ok {
-				return fmt.Errorf("cannot update: rrset %s not found in zone", d.Desired.Key())
-			}
-			if err := c.do(ctx, http.MethodPatch, base+"/"+url.PathEscape(id), tok, toRRSet(*d.Desired), nil); err != nil {
-				return err
-			}
-		case diff.Delete:
-			if d.Actual == nil {
-				return fmt.Errorf("selectel: delete diff without Actual record")
-			}
-			id, ok := idByKey[d.Actual.Key()]
-			if !ok {
-				return fmt.Errorf("cannot delete: rrset %s not found in zone", d.Actual.Key())
-			}
-			if err := c.do(ctx, http.MethodDelete, base+"/"+url.PathEscape(id), tok, nil, nil); err != nil {
-				return err
-			}
+		if err := c.applyOne(ctx, base, tok, idByKey, d); err != nil {
+			// Apply is not atomic: name the failing record and how many
+			// diffs already went through, so the operator can see the state.
+			return fmt.Errorf("%s (применено до ошибки: %d): %w", describeDiff(d), applied, err)
+		}
+		applied++
+	}
+	return nil
+}
+
+// describeDiff renders a diff for error messages: "add CNAME mail.x. [value]".
+func describeDiff(d diff.RecordDiff) string {
+	rec := d.Desired
+	if rec == nil {
+		rec = d.Actual
+	}
+	out := fmt.Sprintf("%s %s", d.Kind, d.Key())
+	if rec != nil {
+		out += fmt.Sprintf(" ttl=%d %q", rec.TTL, rec.Values)
+	}
+	return out
+}
+
+func (c *Client) applyOne(ctx context.Context, base, tok string, idByKey map[string]string, d diff.RecordDiff) error {
+	switch d.Kind {
+	case diff.Add:
+		if d.Desired == nil {
+			return fmt.Errorf("selectel: add/update diff without Desired record")
+		}
+		if err := c.do(ctx, http.MethodPost, base, tok, toRRSet(*d.Desired), nil); err != nil {
+			return err
+		}
+	case diff.Update:
+		if d.Desired == nil {
+			return fmt.Errorf("selectel: add/update diff without Desired record")
+		}
+		id, ok := idByKey[d.Desired.Key()]
+		if !ok {
+			return fmt.Errorf("cannot update: rrset %s not found in zone", d.Desired.Key())
+		}
+		if err := c.do(ctx, http.MethodPatch, base+"/"+url.PathEscape(id), tok, toRRSet(*d.Desired), nil); err != nil {
+			return err
+		}
+	case diff.Delete:
+		if d.Actual == nil {
+			return fmt.Errorf("selectel: delete diff without Actual record")
+		}
+		id, ok := idByKey[d.Actual.Key()]
+		if !ok {
+			return fmt.Errorf("cannot delete: rrset %s not found in zone", d.Actual.Key())
+		}
+		if err := c.do(ctx, http.MethodDelete, base+"/"+url.PathEscape(id), tok, nil, nil); err != nil {
+			return err
 		}
 	}
 	return nil