compile error for import outside package path

closes #2024

there's a new cli option `--main-pkg-path` which you can use to choose
a different root package directory besides the one inferred from the
root source file

and a corresponding build.zig API:
foo.setMainPkgPath(path)

1 files changed, 11 insertions, 0 deletions

diff --git a/std/build.zig b/std/build.zig
index e3fdfbccee..b7f76a53af 100644
--- a/std/build.zig
+++ b/std/build.zig
@@ -859,6 +859,7 @@ pub const LibExeObjStep = struct {
     verbose_cc: bool,
     c_std: Builder.CStd,
     override_std_dir: ?[]const u8,
+    main_pkg_path: ?[]const u8,
     exec_cmd_args: ?[]const ?[]const u8,
     name_prefix: []const u8,
     filter: ?[]const u8,
@@ -950,6 +951,7 @@ pub const LibExeObjStep = struct {
             .c_std = Builder.CStd.C99,
             .system_linker_hack = false,
             .override_std_dir = null,
+            .main_pkg_path = null,
             .exec_cmd_args = null,
             .name_prefix = "",
             .filter = null,
@@ -1098,6 +1100,10 @@ pub const LibExeObjStep = struct {
         self.override_std_dir = dir_path;
     }
 
+    pub fn setMainPkgPath(self: *LibExeObjStep, dir_path: []const u8) void {
+        self.main_pkg_path = dir_path;
+    }
+
     pub fn setOutputPath(self: *LibExeObjStep, file_path: []const u8) void {
         self.output_path = file_path;
 
@@ -1424,6 +1430,11 @@ pub const LibExeObjStep = struct {
             try zig_args.append(builder.pathFromRoot(dir));
         }
 
+        if (self.main_pkg_path) |dir| {
+            try zig_args.append("--main-pkg-path");
+            try zig_args.append(builder.pathFromRoot(dir));
+        }
+
         try builder.spawnChild(zig_args.toSliceConst());
 
         if (self.kind == Kind.Lib and !self.static and self.target.wantSharedLibSymLinks()) {