cram: demonstrate bug with %{bin:public_binary} and absolute DUNE_BUILD_DIR

CHANGES.md

@@ -18,6 +18,9 @@ Unreleased
 
 - Build progress status now shows number of failed jobs (#6242, @Alizter)
 
+- Allow absolute build directories to find public executables. For example,
+  those specified with `(deps %{bin:...})` (#6326, @anmonteiro)
+
 3.5.0 (2022-10-19)
 ------------------
 

src/dune_rules/context.ml

@@ -514,9 +514,8 @@ let create ~(kind : Kind.t) ~path ~env ~env_nodes ~name ~merlin ~targets
       else env
     in
     let env =
-      let cwd = Sys.getcwd () in
       let extend_var var ?(path_sep = Bin.path_sep) v =
-        let v = Filename.concat cwd (Path.Build.to_string v) in
+        let v = Path.to_absolute_filename (Path.build v) in
         match Env.get env var with
         | None -> (var, v)
         | Some prev -> (var, sprintf "%s%c%s" v path_sep prev)

test/blackbox-tests/test-cases/cram/public-name.t

@@ -0,0 +1,30 @@
+Cram and public binaries with an absolute build directory
+
+  $ cat >dune-project <<EOF
+  > (lang dune 2.8)
+  > (cram enable)
+  > (name public-name-exe-test)
+  > EOF
+  $ touch public-name-exe-test.opam
+
+  $ mkdir helper
+  $ cat >helper/dune <<EOF
+  > (executable (public_name helper))
+  > EOF
+  $ cat >helper/helper.ml <<EOF
+  > print_endline "Helper launched successfully";;
+  > EOF
+
+  $ mkdir tests
+  $ cat >tests/run.t <<EOF
+  >   $ helper
+  >   Helper launched successfully
+  > EOF
+  $ echo "(cram (deps %{bin:helper}))" > tests/dune
+
+Running `dune runtest` with a relative build directory works
+
+  $ DUNE_BUILD_DIR=./_other_build dune runtest
+
+  $ export NEW_BUILD_DIR="$PWD/_other_build"
+  $ DUNE_BUILD_DIR="$NEW_BUILD_DIR" dune runtest --auto-promote