Make the output of Dune deterministic in tests (#855)

When the root is not the cwd, print a relative path for the "Entering
..." line rather than an absolute one.

Signed-off-by: Jeremie Dimino <jdimino@janestreet.com>

CHANGES.md

@@ -59,6 +59,9 @@ next
 - Remove hard-coded knowledge of ppx_driver and
   ocaml-migrate-parsetree when using a `dune` file (#576, @diml)
 
+- Make the output of Dune slightly more deterministic when run from
+  inside Dune (#855, @diml)
+
 1.0+beta20 (10/04/2018)
 -----------------------
 

src/scheduler.ml

@@ -161,7 +161,30 @@ let go ?(log=Log.no_log) ?(config=Config.default)
     (Path.to_absolute_filename Path.root |> String.maybe_quoted);
   let cwd = Sys.getcwd () in
   if cwd <> initial_cwd then
-    Printf.eprintf "Entering directory '%s'\n%!" cwd;
+    Printf.eprintf "Entering directory '%s'\n%!"
+      (if Config.inside_dune then
+         let descendant_simple p ~of_ =
+           match
+             String.drop_prefix p ~prefix:of_
+           with
+           | None | Some "" -> None
+           | Some s -> Some (String.sub s ~pos:1 ~len:(String.length s - 1))
+         in
+         match descendant_simple cwd ~of_:initial_cwd with
+         | Some s -> s
+         | None ->
+           match descendant_simple initial_cwd ~of_:cwd with
+           | None -> cwd
+           | Some s ->
+             let rec loop acc dir =
+               if dir = Filename.current_dir_name then
+                 acc
+               else
+                 loop (Filename.concat acc "..") (Filename.dirname dir)
+             in
+             loop ".." (Filename.dirname s)
+       else
+         cwd);
   let t =
     { log
     ; gen_status_line

test/blackbox-tests/test-cases/bad-alias-error/run.t

@@ -1,7 +1,11 @@
-  $ dune runtest --root absolute-path 2>&1 | grep -v Entering
+  $ dune runtest --root absolute-path
+  Entering directory 'absolute-path'
   File "jbuild", line 3, characters 16-24:
   Error: Invalid alias!
   Tried to reference path outside build dir: "/foo/bar"
-  $ dune runtest --root outside-workspace 2>&1 | grep -v Entering
+  [1]
+  $ dune runtest --root outside-workspace
+  Entering directory 'outside-workspace'
   File "jbuild", line 4, characters 16-39:
   Error: path outside the workspace: ./../../../foobar from default
+  [1]

test/blackbox-tests/test-cases/github644/run.t

@@ -6,12 +6,12 @@
 
 These should print something:
 
-  $ dune external-lib-deps --display quiet @runtest
+  $ dune external-lib-deps @runtest
   These are the external library dependencies in the default context:
   - ocaml-migrate-parsetree
   - ppx_that_doesn't_exist
 
-  $ dune external-lib-deps --display quiet --missing @runtest
+  $ dune external-lib-deps --missing @runtest
   Error: The following libraries are missing in the default context:
   - ppx_that_doesn't_exist
   Hint: try: opam install ppx_that_doesn't_exist

test/blackbox-tests/test-cases/github660/run.t

@@ -1,20 +1,24 @@
 When there are explicit interfaces, modules must be rebuilt.
 
-  $ dune runtest --root explicit-interfaces --display quiet -j1 2>&1 | grep -v Entering
+  $ dune runtest --root explicit-interfaces
+  Entering directory 'explicit-interfaces'
           main alias runtest
   hello
   $ echo 'let x = 1' >> explicit-interfaces/lib_sub.ml
-  $ dune runtest --root explicit-interfaces --display quiet -j1 2>&1 | grep -v Entering | grep -v ocamlopt
+  $ dune runtest --root explicit-interfaces
+  Entering directory 'explicit-interfaces'
           main alias runtest
   hello
 
 When there are no interfaces, the situation is the same, but it is not possible
 to rely on these.
 
-  $ dune runtest --root no-interfaces --display quiet -j1 2>&1 | grep -v Entering
+  $ dune runtest --root no-interfaces
+  Entering directory 'no-interfaces'
           main alias runtest
   hello
   $ echo 'let x = 1' >> no-interfaces/lib_sub.ml
-  $ dune runtest --root no-interfaces --display quiet -j1 2>&1 | grep -v Entering | grep -v ocamlopt
+  $ dune runtest --root no-interfaces
+  Entering directory 'no-interfaces'
           main alias runtest
   hello

test/blackbox-tests/test-cases/intf-only/run.t

@@ -1,6 +1,7 @@
 Successes:
 
-  $ dune build --display short --root foo --debug-dep 2>&1 | grep -v Entering
+  $ dune build --display short --root foo --debug-dep
+  Entering directory 'foo'
       ocamldep test/bar.ml.d
       ocamldep foo.ml.d
         ocamlc .foo.objs/foo__.{cmi,cmo,cmt}
@@ -20,7 +21,8 @@ Successes:
 
 Errors:
 
-  $ dune build --display short --root a foo.cma 2>&1 | grep -v Entering
+  $ dune build --display short --root a foo.cma
+  Entering directory 'a'
   File "dune", line 2, characters 1-13:
   Warning: Some modules don't have an implementation.
   You need to add the following field to this stanza:
@@ -30,16 +32,21 @@ Errors:
   This will become an error in the future.
         ocamlc .foo.objs/foo.{cmi,cmo,cmt}
         ocamlc foo.cma
-  $ dune build --display short --root b foo.cma 2>&1 | grep -v Entering
+  $ dune build --display short --root b foo.cma
+  Entering directory 'b'
   File "dune", line 3, characters 34-37:
   Warning: The following modules must be listed here as they don't have an implementation:
   - y
   This will become an error in the future.
         ocamlc .foo.objs/foo.{cmi,cmo,cmt}
         ocamlc foo.cma
-  $ dune build --display short --root c foo.cma 2>&1 | grep -v Entering
+  $ dune build --display short --root c foo.cma
+  Entering directory 'c'
   File "dune", line 3, characters 35-36:
   Error: Module X doesn't exist.
-  $ dune build --display short --root d foo.cma 2>&1 | grep -v Entering
+  [1]
+  $ dune build --display short --root d foo.cma
+  Entering directory 'd'
   File "dune", line 3, characters 35-36:
   Error: Module X has an implementation, it cannot be listed here
+  [1]

test/blackbox-tests/test-cases/odoc-unique-mlds/run.t

@@ -1,5 +1,6 @@
 Duplicate mld's in the same scope
-  $ dune build @doc --display short --root ./same-scope 2>&1 | grep -v Entering
+  $ dune build @doc --display short --root ./same-scope
+  Entering directory 'same-scope'
           odoc _doc/_html/odoc.css
         ocamlc lib1/.root_lib1.objs/root_lib1.{cmi,cmo,cmt}
           odoc _doc/_odoc/lib/root.lib1/root_lib1.odoc
@@ -12,7 +13,8 @@ Duplicate mld's in the same scope
 
 Duplicate mld's in different scope
   $ rm -rf diff-scope/_build
-  $ dune build @doc --display short --root ./diff-scope 2>&1 | grep -v Entering
+  $ dune build @doc --display short --root ./diff-scope
+  Entering directory 'diff-scope'
           odoc _doc/_html/odoc.css
         ocamlc scope1/.scope1.objs/scope1.{cmi,cmo,cmt}
           odoc _doc/_odoc/lib/scope1/scope1.odoc

test/blackbox-tests/test-cases/private-public-overlap/run.t

@@ -1,13 +1,16 @@
 public libraries may not have private dependencies
 
-  $ dune build --display short --root private-dep 2>&1 | grep -v Entering
+  $ dune build --display short --root private-dep
+  Entering directory 'private-dep'
   File "dune", line 10, characters 14-24:
   Error: Library "privatelib" is private, it cannot be a dependency of a public library.
   You need to give "privatelib" a public name.
       ocamldep publiclib.ml.d
+  [1]
 
 On the other hand, public libraries may have private preprocessors
-  $ dune build --display short --root private-rewriter 2>&1 | grep -v Entering
+  $ dune build --display short --root private-rewriter
+  Entering directory 'private-rewriter'
         ocamlc .ppx_internal.objs/ppx_internal.{cmi,cmo,cmt}
       ocamlopt .ppx_internal.objs/ppx_internal.{cmx,o}
       ocamlopt ppx_internal.{a,cmxa}
@@ -21,7 +24,8 @@ On the other hand, public libraries may have private preprocessors
         ocamlc mylib.cma
 
 Unless they introduce private runtime dependencies:
-  $ dune build --display short --root private-runtime-deps 2>&1 | grep -v Entering
+  $ dune build --display short --root private-runtime-deps
+  Entering directory 'private-runtime-deps'
   File "jbuild", line 16, characters 20-31:
   Error: Library "private_runtime_dep" is private, it cannot be a dependency of a public library.
   You need to give "private_runtime_dep" a public name.
@@ -31,14 +35,16 @@ Unless they introduce private runtime dependencies:
       ocamlopt .ppx/jbuild/private_ppx@mylib/ppx.exe
            ppx mylib.pp.ml
       ocamldep mylib.pp.ml.d
+  [1]
 
 However, public binaries may accept private dependencies
-  $ dune build --display short --root exes 2>&1 | grep -v Entering
+  $ dune build --display short --root exes
+  Entering directory 'exes'
       ocamldep publicbin.ml.d
         ocamlc .publicbin.eobjs/publicbin.{cmi,cmo,cmt}
       ocamlopt .publicbin.eobjs/publicbin.{cmx,o}
       ocamlopt publicbin.exe
 
 Private dependencies shouldn't make the library optional
-  $ dune build --display short --root optional 2>&1 | grep -v Entering
+  $ dune build --display short --root optional
-  [1]
+  Entering directory 'optional'

test/blackbox-tests/test-cases/quoting/run.t

@@ -1,15 +1,19 @@
 This behavior is surprising, we should get an error about the fact
 that ${@} is not quoted and doesn't contain exactly 1 element
 
-  $ dune build --root bad x 2>&1 | grep -v Entering
+  $ dune build --root bad x
+  Entering directory 'bad'
   Error: Rule failed to generate the following targets:
   - x
   - y
+  [1]
 
 
 The targets should only be interpreted as a single path when quoted
 
-  $ dune build --root good s 2>&1 | grep -v Entering
+  $ dune build --root good s
+  Entering directory 'good'
   Error: Rule failed to generate the following targets:
   - s
   - t
+  [1]