net: document LookupTXT behavior with multiple strings per record

CL 8966 ("net: allow a dns TXT record to contain more than
one <character-string>") concatenates strings in a TXT record. Document
that behavior, since it's not obvious whether the strings will be
concatenated or accumulated in the returned slice.

Change-Id: I6acb27b296290361a95a6058a056f8e7c2df9a2b
GitHub-Last-Rev: ec0726c7b83a56773d0ac4a86cbfc89c6f4884c9
GitHub-Pull-Request: golang/go#65233
Reviewed-on: https://go-review.googlesource.com/c/go/+/557695
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/net/lookup.go b/src/net/lookup.go
index b04dfa23b9877b0b4afb5967fb764bc903b719fb..f94fd8cefaab1838514aab57c866ec9cfb557a73 100644 (file)
--- a/src/net/lookup.go
+++ b/src/net/lookup.go
@@ -614,6 +614,9 @@ func (r *Resolver) LookupNS(ctx context.Context, name string) ([]*NS, error) {
 
 // LookupTXT returns the DNS TXT records for the given domain name.
 //
+// If a DNS TXT record holds multiple strings, they are concatenated as a
+// single string.
+//
 // LookupTXT uses [context.Background] internally; to specify the context, use
 // [Resolver.LookupTXT].
 func LookupTXT(name string) ([]string, error) {
@@ -621,6 +624,9 @@ func LookupTXT(name string) ([]string, error) {
 }
 
 // LookupTXT returns the DNS TXT records for the given domain name.
+//
+// If a DNS TXT record holds multiple strings, they are concatenated as a
+// single string.
 func (r *Resolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
        return r.lookupTXT(ctx, name)
 }