fix: force symlink dereference when using file command (#1880)

On macOS, the `file` command dereferences symbolic links by default
(`--dereference` implied). On Linux it's the opposite
(`--no-dereference` implied).

We want the dereference behavior on both, otherwise `file` outputs
`symbolic link to Versions/Current/MyFrameworkBinary` on Linux when
checking the file type of an iOS framework (we then fallback to the
`otool` command which fails).

Author: ghugues

swiftpkg/internal/repository_files.bzl

@@ -280,7 +280,7 @@ def _file_type(repository_ctx, path):
         A `string` representing the file type for the path as returned by the
         `file` utility.
     """
-    file_args = ["file", "--brief", path]
+    file_args = ["file", "--dereference", "--brief", path]
     exec_result = repository_ctx.execute(file_args, quiet = True)
     if exec_result.return_code != 0:
         fail("Failed to determine the file type for {path}. stderr:\n{stderr}".format(

swiftpkg/tests/testutils.bzl

@@ -36,9 +36,9 @@ def _new_stub_repository_ctx(
             exec_result = _new_exec_result(
                 stdout = "\n".join(results),
             )
-        elif args_len == 3 and args[0] == "file" and args[1] == "--brief":
-            # Expected command: `file --brief path`
-            path = args[2]
+        elif args_len == 4 and args[0] == "file" and args[1] == "--dereference" and args[2] == "--brief":
+            # Expected command: `file --dereference --brief path`
+            path = args[3]
             results = file_type_results.get(path, "")
             exec_result = _new_exec_result(stdout = results)
         elif args_len == 3 and args[0] == "otool" and args[1] == "-l":