fix(users/edef/depot-scan): properly trace readFile/readDir r/1590

Change-Id: I493e7d20504d34f83a53db50b69e86668874756e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1651
Reviewed-by: edef <edef@edef.eu>
Tested-by: BuildkiteCI

1 files changed, 17 insertions, 0 deletions

diff --git a/users/edef/depot-scan-wrap.nix b/users/edef/depot-scan-wrap.nix
new file mode 100644
index 000000000000..52ea5cc8527b
--- /dev/null
+++ b/users/edef/depot-scan-wrap.nix
@@ -0,0 +1,17 @@
+# this wraps import to override readFile and readDir to trace the files it touches
+# technique inspired by lorri
+{ ... }:
+
+let
+
+  global = {
+    import = global.scopedImport {};
+    scopedImport = x: builtins.scopedImport (global // x);
+    builtins = builtins // {
+      inherit (global) import scopedImport;
+      readFile = path: builtins.trace "depot-scan '${toString path}'" (builtins.readFile path);
+      readDir  = path: builtins.trace "depot-scan '${toString path}'" (builtins.readDir  path);
+    };
+  };
+
+in global.import