test: regression coverage for #447 (skip-trigram canonical file surfaces)

ab8f7cd's Tier 0 rewrite already fixes #447 implicitly — Tier 0 now
builds candidates directly from word_index.search, which captures hits
in skip_trigram_files alongside fully-indexed files. The new test pins
this behavior so a future Tier 0 refactor cannot silently regress.

(PR #456's structural fix on top of the old code is obviated; closing.)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: justrach

src/tests.zig

@@ -11244,6 +11244,46 @@ test "issue-451: scope search surfaces skip-trigram canonical file" {
     try testing.expect(found_canonical);
 }
 
+test "issue-447: searchContent surfaces large (>64KB) skip-trigram files for common identifiers" {
+    var arena = std.heap.ArenaAllocator.init(testing.allocator);
+    defer arena.deinit();
+    var explorer = Explorer.init(arena.allocator());
+
+    var i: usize = 0;
+    while (i < 12) : (i += 1) {
+        var path_buf: [32]u8 = undefined;
+        const path = try std.fmt.bufPrint(&path_buf, "small_{d}.zig", .{i});
+        try explorer.indexFile(path, "fn s() void { _ = widgetX; }\n");
+    }
+
+    const canonical_content =
+        "fn canonical() void {\n" ++
+        "    _ = widgetX;\n" ++
+        "    _ = widgetX;\n" ++
+        "    _ = widgetX;\n" ++
+        "    _ = widgetX;\n" ++
+        "    _ = widgetX;\n" ++
+        "}\n";
+    try explorer.indexFileSkipTrigram("canonical.zig", canonical_content);
+
+    const results = try explorer.searchContent("widgetX", testing.allocator, 5);
+    defer {
+        for (results) |r| {
+            testing.allocator.free(r.line_text);
+            testing.allocator.free(r.path);
+        }
+        testing.allocator.free(results);
+    }
+
+    var found_canonical = false;
+    for (results) |r| {
+        if (std.mem.eql(u8, r.path, "canonical.zig")) found_canonical = true;
+    }
+    try testing.expect(found_canonical);
+}
+
+
+
 test "rerank-trace: appends one JSON line per searchContent when enabled" {
     const tmp_io = testing.io;
     var tmp = testing.tmpDir(.{});