Document and test ? wildcards in network proxy domain patterns (#46027)

## What changed

Document the existing `?` wildcard behavior: it matches exactly one character,
including a dot, in allow and deny patterns. For example, `api?.example.com`
matches `api1.example.com`, but not `api.example.com` or `api12.example.com`.

## Testing

Add table-driven tests for both allowlist and denylist compilation, covering
single and repeated `?` wildcards, combinations with `*`, `*.`, and `**.`,
dot matching, and host and pattern normalization.

GitOrigin-RevId: dd5cd1817c6ea0b701335a38a57fbb5e8039c284

codex-rs/network-proxy/README.md

@@ -214,6 +214,9 @@ what it can reasonably guarantee.
 
 - Allowlist-first policy: if `domains` has no `allow` entries, requests are blocked until an allowlist is configured.
 - Domain patterns: exact hosts are supported, `*.example.com` matches subdomains only, and `**.example.com` matches the apex plus subdomains; the global `*` wildcard is only accepted when explicitly enabled for allowlist compilation and is otherwise rejected.
+- Within a domain pattern, `?` matches exactly one character, including a dot. For example,
+  `api?.example.com` matches `api1.example.com`, but not `api.example.com` or `api12.example.com`.
+  It can be combined with `*`, `*.`, and `**.` in both allow and deny entries.
 - Deny wins: `domains` entries marked `deny` always override the allowlist.
 - Local/private network protection: when `allow_local_binding = false`, the proxy blocks loopback
   and common private/link-local ranges. Explicit allowlisting of local IP literals (or `localhost`)

codex-rs/network-proxy/src/policy.rs

@@ -200,6 +200,9 @@ pub(crate) fn compile_denylist_globset(patterns: &[String]) -> Result<GlobSet> {
     compile_globset_with_policy(patterns, GlobalWildcard::Reject)
 }
 
+// Browser network-policy matchers implement a subset of this hostname grammar.
+// Keep changes to shared grammar and normalization in sync with their contract
+// cases and the Rust tests below, including compile_globset_supports_question_mark_wildcards.
 fn compile_globset_with_policy(
     patterns: &[String],
     global_wildcard: GlobalWildcard,
@@ -217,6 +220,7 @@ fn compile_globset_with_policy(
         // - "example.com": match the exact host
         // - "*.example.com": match any subdomain (not the apex)
         // - "**.example.com": match the apex and any subdomain
+        // - "api?.example.com": match exactly one character after "api"
         // - "*": match every host when explicitly enabled for allowlist compilation
         for candidate in expand_domain_pattern(&pattern) {
             if !seen.insert(candidate.clone()) {
@@ -411,6 +415,46 @@ mod tests {
         assert_eq!(false, set.is_match("foo.region1.v2.argotunnel.com"));
     }
 
+    // Keep this table one-for-one with the browser network-policy matchers'
+    // question-mark contract cases so grammar changes are checked on both sides.
+    #[test]
+    fn compile_globset_supports_question_mark_wildcards() -> Result<()> {
+        for (pattern, host, expected) in [
+            ("api?.example.com", "api1.example.com", true),
+            ("api?.example.com", "api.example.com", false),
+            ("api?.example.com", "api12.example.com", false),
+            ("api??.example.com", "api12.example.com", true),
+            ("api??.example.com", "api1.example.com", false),
+            ("api*?.example.com", "api.example.com", false),
+            ("api*?.example.com", "api1.example.com", true),
+            ("api*?.example.com", "api123.example.com", true),
+            ("api?example.com", "api.example.com", true),
+            ("*.api?.example.com", "api1.example.com", false),
+            ("*.api?.example.com", "www.api1.example.com", true),
+            ("*.api?.example.com", "nested.www.api1.example.com", true),
+            ("*.api?.example.com", "www.api12.example.com", false),
+            ("**.api?.example.com", "api1.example.com", true),
+            ("**.api?.example.com", "www.api1.example.com", true),
+            ("**.api?.example.com", "nested.www.api1.example.com", true),
+            ("**.api?.example.com", "api12.example.com", false),
+            ("**.api?.example.com", "www.api12.example.com", false),
+            (" API?.EXAMPLE.COM. ", "API1.EXAMPLE.COM.", true),
+        ] {
+            let patterns = [pattern.to_string()];
+            for set in [
+                compile_allowlist_globset(&patterns)?,
+                compile_denylist_globset(&patterns)?,
+            ] {
+                assert_eq!(
+                    set.is_match(normalize_host(host)),
+                    expected,
+                    "pattern {pattern}, host {host}"
+                );
+            }
+        }
+        Ok(())
+    }
+
     #[test]
     fn compile_globset_normalizes_apex_and_subdomains() {
         let set = compile_denylist_globset(&["**.Example.COM.".to_string()]).unwrap();