From 488f32c5d4f16a23e3f2e74efc5701bd9c7b51b9 Mon Sep 17 00:00:00 2001
From: Rudi Grinberg <me@rgrinberg.com>
Date: Thu, 21 Oct 2021 15:10:05 -0600
Subject: [PATCH] fix(cram): remove cram file after it is read

Tests shouldn't be able to observe the test files. However, we must
restore the file if we observe a diff.

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

ps-id: 9962A972-82F0-4FB5-A8C9-D9B91083F09C
---
 src/dune_rules/cram_exec.ml                               | 8 ++++++++
 test/blackbox-tests/test-cases/github3857.t               | 1 -
 test/blackbox-tests/test-cases/menhir/promote.t/run.t     | 1 -
 .../blackbox-tests/test-cases/meta-template-version-bug.t | 1 +
 4 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/dune_rules/cram_exec.ml b/src/dune_rules/cram_exec.ml
index b2042a405a7..7f462a8e724 100644
--- a/src/dune_rules/cram_exec.ml
+++ b/src/dune_rules/cram_exec.ml
@@ -135,6 +135,12 @@ let cram_stanzas lexbuf =
 
 let run_expect_test file ~f =
   let file_contents = Io.read_file ~binary:false file in
+  (* Nasty hack so that the user doesn't observe the test file while running the
+     test.
+
+     Eventually, we should just have a way to read the source from outside the
+     sandbox. *)
+  Path.unlink_no_err file;
   let open Fiber.O in
   let+ expected =
     let lexbuf =
@@ -144,6 +150,8 @@ let run_expect_test file ~f =
   in
   let corrected_file = Path.extend_basename file ~suffix:".corrected" in
   if file_contents <> expected then
+    (* we only need to restore the test file so the diff doesn't fail *)
+    let () = Io.write_file file file_contents in
     Io.write_file ~binary:false corrected_file expected
   else if Path.exists corrected_file then
     Path.rm_rf corrected_file
diff --git a/test/blackbox-tests/test-cases/github3857.t b/test/blackbox-tests/test-cases/github3857.t
index c39f305aa35..115607514db 100644
--- a/test/blackbox-tests/test-cases/github3857.t
+++ b/test/blackbox-tests/test-cases/github3857.t
@@ -3,4 +3,3 @@ dune install should not write anything to _build/
   $ dune install --prefix _install
   $ ls .
   dune-project
-  github3857.t
diff --git a/test/blackbox-tests/test-cases/menhir/promote.t/run.t b/test/blackbox-tests/test-cases/menhir/promote.t/run.t
index cdc3cfe6538..69409ff8990 100644
--- a/test/blackbox-tests/test-cases/menhir/promote.t/run.t
+++ b/test/blackbox-tests/test-cases/menhir/promote.t/run.t
@@ -14,4 +14,3 @@ Check what is being generated exactly:
   parser.ml
   parser.mli
   parser.mly
-  run.t
diff --git a/test/blackbox-tests/test-cases/meta-template-version-bug.t b/test/blackbox-tests/test-cases/meta-template-version-bug.t
index 121ec4655e7..21cbdf81bdd 100644
--- a/test/blackbox-tests/test-cases/meta-template-version-bug.t
+++ b/test/blackbox-tests/test-cases/meta-template-version-bug.t
@@ -2,6 +2,7 @@ This test demonstrates a bug when there's a package with a meta template and a
 custom version:
 
   $ git init -q
+  $ touch foo
   $ git add .
   $ git commit -qm _
   $ git tag -a 1.0 -m 1.0