fix(resolve): avoid removing enums needed by extensions

Core removes some enums, but some extensions need them, e.g.
GL_VERTEX_ARRAY is required by GL_KHR_debug.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Author: tycho

src/resolve.rs

@@ -315,6 +315,9 @@ fn resolve_feature_set(
                 }
                 req_types.extend(require.types.iter().cloned());
                 req_enums.extend(require.enums.iter().cloned());
+                for e in &require.enums {
+                    removed_enums.remove(e.as_str());
+                }
                 for cmd in &require.commands {
                     // Core commands already in req_commands stay there.
                     if !req_commands.contains_key(cmd.as_str()) {

tests/generate_c.rs

@@ -352,6 +352,8 @@ fn generated_header_does_not_contain_removed_compat_enums_in_core() {
         .args([
             "--api",
             "gl:core=3.3",
+            "--extensions",
+            "",
             "--out-path",
             dir.path().to_str().unwrap(),
             "c",
@@ -368,3 +370,31 @@ fn generated_header_does_not_contain_removed_compat_enums_in_core() {
         "GL_QUADS should be absent in core profile"
     );
 }
+
+#[test]
+fn removed_enums_readded_by_extensions() {
+    // In core profile, deprecated constants like GL_QUADS get removed, *except* when they're
+    // required by extensions.
+    let dir = TempDir::new().unwrap();
+    gloam()
+        .args([
+            "--api",
+            "gl:core=3.3",
+            "--extensions",
+            "GL_ARB_tessellation_shader",
+            "--out-path",
+            dir.path().to_str().unwrap(),
+            "c",
+        ])
+        .assert()
+        .success();
+
+    let header =
+        std::fs::read_to_string(dir.path().join("include").join("gloam").join("gl.h")).unwrap();
+
+    // GL_QUADS is removed in core profile — it must not appear.
+    assert!(
+        header.contains("GL_QUADS "),
+        "GL_QUADS should be in core profile with GL_ARB_tessellation_shader"
+    );
+}