Lspinfo lists pardes's own dependency imports only for a file in pardes's tree

The in-process ZLS's report listed the module map of the build pardes came from (vaxis, ghostty and the rest) for any .zig file, a project that has none of them included. It now lists them only for a file in that tree (project_root, a build option), and says there are none for any other.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

2 files changed, 24 insertions, 4 deletions

diff --git a/build.zig b/build.zig
index 79de8a81..b43f3fd9 100644
--- a/build.zig
+++ b/build.zig
@@ -752,6 +752,8 @@ pub fn build(b: *std.Build) void {
     for ([_]?*std.Build.Step.Options{ opts, gui_opts }) |maybe| if (maybe) |o| {
         o.addOption([]const []const u8, "module_names", mod_names);
         o.addOption([]const []const u8, "module_roots", mod_roots);
+        // Whose imports those are: a .zig file outside this tree has none of them.
+        o.addOption([]const u8, "project_root", b.build_root.path orelse "");
     };
 
     const iso_off = b.addOptions();
diff --git a/src/lsp/lsp_zls.zig b/src/lsp/lsp_zls.zig
index 09493c26..2311ec47 100644
--- a/src/lsp/lsp_zls.zig
+++ b/src/lsp/lsp_zls.zig
@@ -354,10 +354,14 @@ fn status(arena: std.mem.Allocator, req: lsp.Req, out: *std.Io.Writer) !void {
     // The dependency module map, which is the answer to "why does gd work on
     // std and not on @import(\"vaxis\")" — if a name is not on this list, the
     // build did not import it and nothing can resolve it.
-    try out.print("\ndependency imports gd can follow ({d}):\n", .{cfg.module_names.len});
-    for (cfg.module_names, cfg.module_roots) |n, r| {
-        try out.print("  {s:<14} {s}\n", .{ n, r });
-    }
+    // pardes's own build's imports: listed for a file in its tree, none for
+    // any other project's file, which does not have them.
+    if (inProject(req.path)) {
+        try out.print("\ndependency imports gd can follow ({d}):\n", .{cfg.module_names.len});
+        for (cfg.module_names, cfg.module_roots) |n, r| {
+            try out.print("  {s:<14} {s}\n", .{ n, r });
+        }
+    } else try out.print("\ndependency imports gd can follow: none (this file is not in the tree pardes was built from)\n", .{});
     try out.print("asked from: {s}\n", .{if (req.path.len == 0) "a pane with no file" else req.path});
 
     try out.print("\nanswers:", .{});
@@ -426,6 +430,20 @@ fn status(arena: std.mem.Allocator, req: lsp.Req, out: *std.Io.Writer) !void {
 ///     running ITS build.zig.
 ///  3. A module whose root source is a GENERATED file is absent from the
 ///     table: it has no path until make() runs.
+/// Whether `path` is in the tree pardes was built from, whose build's
+/// imports `cfg.module_names` are.
+fn inProject(path: []const u8) bool {
+    const project = std.mem.trimEnd(u8, cfg.project_root, "/");
+    return project.len > 0 and path.len > project.len and std.mem.startsWith(u8, path, project) and path[project.len] == '/';
+}
+
+test "only a file in pardes's own tree is told pardes's dependency imports" {
+    var buf: [4096]u8 = undefined;
+    const inside = try std.fmt.bufPrint(&buf, "{s}/src/main.zig", .{std.mem.trimEnd(u8, cfg.project_root, "/")});
+    try std.testing.expect(inProject(inside));
+    try std.testing.expect(!inProject("/tmp/elsewhere/main.zig"));
+}
+
 fn moduleRoot(name: []const u8) ?[]const u8 {
     comptime std.debug.assert(cfg.module_names.len == cfg.module_roots.len);
     for (cfg.module_names, cfg.module_roots) |n, r| {