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Make Merlin look for dot-merlin-reader in the install directory (#179)
* Make Merlin look for dot-merlin-reader in the install directory * Use realpath
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‎src/kernel/mconfig_dot.ml‎

Lines changed: 35 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,34 @@ end = struct
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| Dot_merlin -> "dot-merlin-reader"
130130
| Dune -> "dune"
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132+
let find_exe = function
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| Dot_merlin ->
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(* 1. If DOT_MERLIN_READER_EXE is defined, then use its value for the
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dot-merlin-reader exe
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2. If not, look in the same directory as the merlin executable for a
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dot-merlin-reader.
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3. If not, fallback to using whatever one is on the PATH. *)
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let get_from_env_var = lazy (Sys.getenv_opt "DOT_MERLIN_READER_EXE") in
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let get_from_same_dir_as_merlin_exe =
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lazy
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(let merlin_exe = Unix.realpath Sys.executable_name in
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let merlin_bin = Filename.dirname merlin_exe in
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let dot_merlin_reader_exe =
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Filename.concat merlin_bin "dot-merlin-reader"
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in
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match Sys.file_exists dot_merlin_reader_exe with
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| true -> Some dot_merlin_reader_exe
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| false -> None)
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in
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List.find_map_opt
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[ get_from_env_var; get_from_same_dir_as_merlin_exe ]
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~f:Lazy.force
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|> Option.value ~default:"dot-merlin-reader"
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| Dune ->
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(* Always use the dune on the PATH *)
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(* CR-someday: consider doing something better here *)
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"dune"
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132160
exception Process_exited
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module Process = struct
@@ -148,10 +176,10 @@ end = struct
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let prog, args =
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match cfg with
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| Dot_merlin ->
151-
let prog = "dot-merlin-reader" in
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let prog = find_exe Dot_merlin in
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(prog, [| prog |])
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| Dune ->
154-
let prog = "dune" in
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let prog = find_exe Dune in
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(prog, [| prog; "ocaml-merlin"; "--no-print-directory" |])
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in
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let cwd = Sys.getcwd () in
@@ -393,8 +421,11 @@ let get_config { workdir; process_dir; configurator } path_abs =
393421
| Unix.Unix_error (ENOENT, "create_process", "dot-merlin-reader") ->
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let error =
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Printf.sprintf
396-
"%s could not find `dot-merlin-reader` in the PATH. Please make sure \
397-
that `dot-merlin-reader` is installed and in the PATH."
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"%s could not find `dot-merlin-reader`. Please make sure that \
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`dot-merlin-reader` is installed. `dot-merlin-reader` is expected to \
426+
be in the same directory as the merlin executable or on the PATH. You \
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may also specify the path to `dot-merlin-reader` via the \
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`DOT_MERLIN_READER_EXE` environment variable."
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(Lib_config.program_name ())
399430
in
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(empty_config, [ error ])

‎src/utils/std.ml‎

Lines changed: 9 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -109,12 +109,17 @@ module List = struct
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| None -> filter_map ~f xs
110110
| Some x -> x :: filter_map ~f xs)
111111

112-
let rec find_map ~f = function
113-
| [] -> raise Not_found
112+
let rec find_map_opt ~f = function
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| [] -> None
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| x :: xs -> (
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match f x with
116-
| None -> find_map ~f xs
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| Some x' -> x')
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| None -> find_map_opt ~f xs
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| Some x' -> Some x')
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119+
let find_map ~f l =
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match find_map_opt ~f l with
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| None -> raise Not_found
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| Some x -> x
118123

119124
let rec map_end ~f l1 l2 =
120125
match l1 with

‎tests/test-dirs/config/dot-merlin-reader/find-dot-merlin-reader.t‎

Lines changed: 69 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,69 @@
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$ cat > .merlin <<EOF
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> UNIT_NAME Dot_merlin_was_successfully_read
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> EOF
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In real-world scenarios, ocamlmerlin and dot-merlin-reader are usually installed in the
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same directory (for example, via an opam install). In this situation, if dot-merlin-reader
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isn't on the PATH, we can still read the .merlin file.
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$ mkdir merlin-bin
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$ cp $(which dot-merlin-reader) merlin-bin
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$ cp $(which ocamlmerlin) merlin-bin
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$ cp $(which ocamlmerlin-server) merlin-bin
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$ cp $(which ocaml-index) merlin-bin
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$ PATH="" merlin-bin/ocamlmerlin single dump-configuration -filename test.ml \
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> | jq .value.merlin.unit_name -r
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Dot_merlin_was_successfully_read
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If ocamlmerlin is a symlink, it looks in the original install directory.
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$ mkdir merlin-bin-symlink
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$ ln -s $(realpath merlin-bin/ocamlmerlin) merlin-bin-symlink/ocamlmerlin
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$ PATH="" merlin-bin-symlink/ocamlmerlin single dump-configuration -filename test.ml \
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> | jq .value.merlin.unit_name -r
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Dot_merlin_was_successfully_read
27+
28+
The dot-merlin-reader in the same directory is prioritized over the one on the PATH.
29+
$ mkdir bad-dot-merlin-reader-bin
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$ cat > bad-dot-merlin-reader-bin/dot-merlin-reader <<EOF
31+
> #!/bin/sh
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> echo "this is a bad dot-merlin-reader" >&2
33+
> exit 1
34+
> EOF
35+
36+
$ PATH="bad-dot-merlin-reader-bin" \
37+
> merlin-bin/ocamlmerlin single dump-configuration -filename test.ml \
38+
> | jq .value.merlin.unit_name -r
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Dot_merlin_was_successfully_read
40+
41+
But we can fall back to the one on the PATH if a dot-merlin-reader doesn't exist in the
42+
same directory.
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$ cp -r merlin-bin merlin-bin-no-reader
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$ rm merlin-bin-no-reader/dot-merlin-reader
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$ PATH="" \
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> merlin-bin-no-reader/ocamlmerlin single dump-configuration -filename test.ml \
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> | jq .value.merlin.unit_name -r
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null
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$ PATH="merlin-bin" \
52+
> merlin-bin-no-reader/ocamlmerlin single dump-configuration -filename test.ml \
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> | jq .value.merlin.unit_name -r
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Dot_merlin_was_successfully_read
55+
56+
We can override using the DOT_MERLIN_READER_EXE environment variable.
57+
$ cp -r merlin-bin merlin-bin-bad-reader
58+
$ rm merlin-bin-bad-reader/dot-merlin-reader
59+
$ cp bad-dot-merlin-reader-bin/dot-merlin-reader merlin-bin-bad-reader
60+
61+
$ PATH="merlin-bin-bad-reader" \
62+
> merlin-bin-bad-reader/ocamlmerlin single dump-configuration -filename test.ml \
63+
> | jq .value.merlin.unit_name -r
64+
null
65+
66+
$ PATH="merlin-bin-bad-reader" DOT_MERLIN_READER_EXE="merlin-bin/dot-merlin-reader" \
67+
> merlin-bin-bad-reader/ocamlmerlin single dump-configuration -filename test.ml \
68+
> | jq .value.merlin.unit_name -r
69+
Dot_merlin_was_successfully_read

‎tests/test-dirs/config/no-dune.t‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -27,5 +27,5 @@
2727

2828
$ cat output | jq '.value.merlin.failures'
2929
[
30-
"Merlin could not find `dot-merlin-reader` in the PATH. Please make sure that `dot-merlin-reader` is installed and in the PATH."
30+
"Merlin could not find `dot-merlin-reader`. Please make sure that `dot-merlin-reader` is installed. `dot-merlin-reader` is expected to be in the same directory as the merlin executable or on the PATH. You may also specify the path to `dot-merlin-reader` via the `DOT_MERLIN_READER_EXE` environment variable."
3131
]

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