fix: enumerate RestrictAddressFamilies= AF_ names instead of loose regex

config_parse_address_families resolves each name through af_from_name, whose set
is generated from the AF_* macros in <sys/socket.h> (minus AF_UNSPEC/AF_MAX). The
validator matched the loose RegexTerminal("AF_[A-Z0-9_]+"), so any AF_-prefixed
token (AF_BOGUS, AF_INETZ, AF_DECNET) passed validation incorrectly.

Replace it with a FlexibleLiteralChoiceTerminal enumerating the real names: it
still matches the shape leniently (so coloring / error localization keep working)
but is semantically valid only for an exact name. This is a correctness fix on
the default path (both engines), and it sets up grammar-based completion and the
valid-but-kernel-removed deprecation annotator (AF_DECnet, AF_IRDA, ...).

Tests: adds enumerated-valid and unknown-rejected cases to the validator test;
now that AF_BOGUS is honestly invalid, the grammar-engine e2e test uses it to
cover the SemanticError -> highlight mapping (replacing a 242.x-safe workaround).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Steve Ramage

src/main/kotlin/net/sjrx/intellij/plugins/systemdunitfiles/semanticdata/optionvalues/ai/ConfigParseAddressFamiliesOptionValue.kt

@@ -10,11 +10,21 @@ import net.sjrx.intellij.plugins.systemdunitfiles.semanticdata.optionvalues.gram
  * in src/shared/parse-helpers.c:90. Accepts:
  *   - "none" (clears the set, sets allowlist)
  *   - optional leading "~" (invert / denylist mode), followed by a whitespace-separated list
- *     of address family names from af_from_name (AF_UNIX, AF_INET, AF_INET6, AF_NETLINK,
- *     AF_PACKET, …)
+ *     of address family names resolved by af_from_name
  *
- * The grammar matches the "AF_" prefix loosely (any uppercase/digit/underscore tail); unknown
- * names slip past the grammar but fail at runtime. This is the same tradeoff as syscall_errno.
+ * The name set is the list of AF_* macros systemd's af_from_name knows about, which is
+ * generated (src/basic/generate-af-list.sh) from the AF_* #defines in <sys/socket.h>, minus
+ * AF_UNSPEC and AF_MAX. It can be reproduced by preprocessing <sys/socket.h> with
+ * `cpp -dM`, keeping the `#define AF_*` lines (dropping AF_UNSPEC/AF_MAX), and taking the macro
+ * names.
+ *
+ * Enumerating the names exactly (rather than the old loose RegexTerminal("AF_[A-Z0-9_]+"))
+ * makes validation correct (AF_BOGUS is now rejected) and sets up grammar-based completion.
+ *
+ * Note: some of these names still resolve via af_from_name (the macro exists in libc headers)
+ * even though the kernel removed the protocol — AF_DECnet (Linux 6.1), AF_IRDA (4.17),
+ * AF_ECONET (3.5), AF_WANPIPE (2.6.21). These are valid-but-removed and are intended targets
+ * of a future deprecation annotator (see GitHub #467 / address_families(7)).
  */
 class ConfigParseAddressFamiliesOptionValue : SimpleGrammarOptionValues(
     "config_parse_address_families",
@@ -23,13 +33,71 @@ class ConfigParseAddressFamiliesOptionValue : SimpleGrammarOptionValues(
             LiteralChoiceTerminal("none"),
             SequenceCombinator(
                 ZeroOrOne(LiteralChoiceTerminal("~")),
-                RegexTerminal("AF_[A-Z0-9_]+", "AF_[A-Z0-9_]+"),
+                ADDRESS_FAMILY,
                 ZeroOrMore(SequenceCombinator(
                     WhitespaceTerminal(),
-                    RegexTerminal("AF_[A-Z0-9_]+", "AF_[A-Z0-9_]+")
+                    ADDRESS_FAMILY
                 ))
             )
         ),
         EOF()
     )
-)
+) {
+    companion object {
+        /**
+         * The AF_* names systemd's af_from_name accepts. FlexibleLiteralChoiceTerminal matches
+         * loosely for syntax (so coloring / error localization still work) but requires an exact
+         * choice to be semantically valid.
+         */
+        private val ADDRESS_FAMILY = FlexibleLiteralChoiceTerminal(
+            "AF_ALG",
+            "AF_APPLETALK",
+            "AF_ASH",
+            "AF_ATMPVC",
+            "AF_ATMSVC",
+            "AF_AX25",
+            "AF_BLUETOOTH",
+            "AF_BRIDGE",
+            "AF_CAIF",
+            "AF_CAN",
+            "AF_DECnet",
+            "AF_ECONET",
+            "AF_FILE",
+            "AF_IB",
+            "AF_IEEE802154",
+            "AF_INET",
+            "AF_INET6",
+            "AF_IPX",
+            "AF_IRDA",
+            "AF_ISDN",
+            "AF_IUCV",
+            "AF_KCM",
+            "AF_KEY",
+            "AF_LLC",
+            "AF_LOCAL",
+            "AF_MCTP",
+            "AF_MPLS",
+            "AF_NETBEUI",
+            "AF_NETLINK",
+            "AF_NETROM",
+            "AF_NFC",
+            "AF_PACKET",
+            "AF_PHONET",
+            "AF_PPPOX",
+            "AF_QIPCRTR",
+            "AF_RDS",
+            "AF_ROSE",
+            "AF_ROUTE",
+            "AF_RXRPC",
+            "AF_SECURITY",
+            "AF_SMC",
+            "AF_SNA",
+            "AF_TIPC",
+            "AF_UNIX",
+            "AF_VSOCK",
+            "AF_WANPIPE",
+            "AF_X25",
+            "AF_XDP"
+        )
+    }
+}

src/test/kotlin/net/sjrx/intellij/plugins/systemdunitfiles/inspections/GrammarParseEngineInspectionTest.kt

@@ -48,14 +48,15 @@ class GrammarParseEngineInspectionTest : AbstractUnitFileTest() {
   @Test
   fun testInvalidAddressFamiliesUnderNewEngine() {
     enableNewEngine()
-    // Three malformed lists, each ill-formed against the grammar's shape -> one highlight each:
-    // a stray comma, a name without the AF_ prefix, and a lowercase tail the AF_* regex rejects.
+    // One highlight each, exercising both ParseOutcome failure kinds now that AF names are
+    // enumerated: AF_BOGUS is well-formed but unknown (SemanticError), while the comma and the
+    // bare non-AF token are ill-formed against the grammar shape (SyntaxError).
     // language="unit file (systemd)"
     val file = """
             [Service]
+            RestrictAddressFamilies=AF_BOGUS
             RestrictAddressFamilies=AF_INET, AF_INET6
             RestrictAddressFamilies=inet
-            RestrictAddressFamilies=AF_inet
         """.trimIndent()
 
     setupFileInEditor("file.service", file)

src/test/kotlin/net/sjrx/intellij/plugins/systemdunitfiles/inspections/ai/ConfigParseAddressFamiliesOptionValueTest.kt

@@ -27,6 +27,27 @@ class ConfigParseAddressFamiliesOptionValueTest : AbstractUnitFileTest() {
         assertSize(0, highlights)
     }
 
+    @Test
+    fun testValidEnumeratedFamilies() {
+        // Names that the previous loose RegexTerminal happened to accept but that we now want to
+        // keep accepting: an alias (AF_LOCAL), a mixed-case real name (AF_DECnet), the newest
+        // families, and a long whitespace-separated list including the inversion prefix.
+        // language="unit file (systemd)"
+        val file = """
+            [Service]
+            RestrictAddressFamilies=AF_LOCAL
+            RestrictAddressFamilies=AF_DECnet
+            RestrictAddressFamilies=AF_VSOCK AF_XDP AF_MCTP
+            RestrictAddressFamilies=~AF_UNIX AF_INET AF_INET6 AF_NETLINK AF_PACKET
+        """.trimIndent()
+
+        setupFileInEditor("file.service", file)
+        enableInspection(InvalidValueInspection::class.java)
+        val highlights = myFixture.doHighlighting()
+
+        assertSize(0, highlights)
+    }
+
     @Test
     fun testInvalidValues() {
         // language="unit file (systemd)"
@@ -45,4 +66,27 @@ class ConfigParseAddressFamiliesOptionValueTest : AbstractUnitFileTest() {
 
         assertSize(5, highlights)
     }
+
+    @Test
+    fun testUnknownFamiliesAreNowRejected() {
+        // Regression guard for the grammar fix: the old RegexTerminal("AF_[A-Z0-9_]+") accepted
+        // any AF_-prefixed token, so these passed validation incorrectly. With the enumerated
+        // family set they must be flagged (syntactically well-formed, semantically invalid).
+        // Raw values (no <error> markup) so the guard does not depend on markup stripping; each
+        // invalid property contributes exactly one highlight.
+        // language="unit file (systemd)"
+        val file = """
+            [Service]
+            RestrictAddressFamilies=AF_BOGUS
+            RestrictAddressFamilies=AF_INETZ
+            RestrictAddressFamilies=AF_INET AF_MADEUP
+            RestrictAddressFamilies=AF_DECNET
+        """.trimIndent()
+
+        setupFileInEditor("file.service", file)
+        enableInspection(InvalidValueInspection::class.java)
+        val highlights = myFixture.doHighlighting()
+
+        assertSize(4, highlights)
+    }
 }