- Fix edns subnet, that scope zero queries, when there is a

subquery without subnet, and the forward-no-cache or
  stub-no-cache option is set, it is not stored in cache due to
  the forward or stub option.
This has the changelog entry and test.

doc/Changelog

@@ -1,3 +1,9 @@
+6 January 2026: Wouter
+	- Fix edns subnet, that scope zero queries, when there is a
+	  subquery without subnet, and the forward-no-cache or
+	  stub-no-cache option is set, it is not stored in cache due to
+	  the forward or stub option.
+
 31 December 2025: Yorgos
 	- Update the unbound-anchor man page to note write permissions of the
 	  generated file if it is to be used with Unbound's

testdata/subnet_scopezero_global_nocache.crpl

@@ -0,0 +1,126 @@
+; config options
+server:
+	target-fetch-policy: "0 0 0 0 0"
+	module-config: "subnetcache validator iterator"
+	verbosity: 4
+	qname-minimisation: no
+	; the domain is not configured for edns-subnet
+	;send-client-subnet: 1.2.3.4
+
+stub-zone:
+	name: "."
+	stub-addr: 193.0.14.129
+
+stub-zone:
+	name: "example.com"
+	stub-addr: 1.2.3.4
+	stub-no-cache: yes
+CONFIG_END
+
+SCENARIO_BEGIN Test subnet cache with scope zero for global cache store.
+
+; the upstream server.
+RANGE_BEGIN 0 100
+	ADDRESS 193.0.14.129
+
+ENTRY_BEGIN
+MATCH opcode qtype qname ednsdata
+ADJUST copy_id
+REPLY QR NOERROR
+SECTION QUESTION
+. IN NS
+SECTION ANSWER
+. IN NS K.ROOT-SERVERS.NET.
+SECTION ADDITIONAL
+HEX_EDNSDATA_BEGIN
+	;; we expect to receive empty
+HEX_EDNSDATA_END
+K.ROOT-SERVERS.NET.     IN      A       193.0.14.129
+ENTRY_END
+RANGE_END
+
+RANGE_BEGIN 0 21
+	ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR AA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. IN A   10.20.30.40
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+RANGE_END
+
+RANGE_BEGIN 30 50
+	ADDRESS 1.2.3.4
+ENTRY_BEGIN
+MATCH opcode qtype qname
+ADJUST copy_id
+REPLY QR AA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. IN A   10.20.30.1
+SECTION AUTHORITY
+SECTION ADDITIONAL
+ENTRY_END
+RANGE_END
+
+; query for 0.0.0.0/0
+STEP 10 QUERY
+ENTRY_BEGIN
+HEX_ANSWER_BEGIN
+	00 00 01 00 00 01 00 00         ;ID 0
+	00 00 00 01 03 77 77 77         ; www.example.com A? (DO)
+	07 65 78 61 6d 70 6c 65
+	03 63 6f 6d 00 00 01 00
+	01 00 00 29 10 00 00 00
+	80 00 00 08
+
+	00 08 00 04                     ; OPC, optlen
+	00 01 00 00                     ; ip4, scope 0, source 0
+	                                ;0.0.0.0/0
+HEX_ANSWER_END
+ENTRY_END
+
+STEP 20 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ednsdata
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. IN A   10.20.30.40
+SECTION AUTHORITY
+SECTION ADDITIONAL
+HEX_EDNSDATA_BEGIN
+	00 08           ; OPC
+	00 04           ; option length
+	00 01           ; Family
+	00 00           ; source mask, scopemask
+	                ; address
+HEX_EDNSDATA_END
+ENTRY_END
+
+; It should not be in global cache.
+STEP 30 QUERY
+ENTRY_BEGIN
+REPLY RD NOERROR
+SECTION QUESTION
+www.example.com. IN A
+ENTRY_END
+
+STEP 40 CHECK_ANSWER
+ENTRY_BEGIN
+MATCH all ednsdata
+REPLY QR RD RA NOERROR
+SECTION QUESTION
+www.example.com. IN A
+SECTION ANSWER
+www.example.com. IN A   10.20.30.1
+ENTRY_END
+
+SCENARIO_END