Take file kind from --name when formatting stdin (#1119)

* Add tests, stdin_and_name failing
* With stdin, take file kind from --name

Closes #1112

CHANGES.md

@@ -1,5 +1,6 @@
 ### (master)
 
+  + Internal: Take file kind from --name when formatting stdin (#1119) (Jules Aguillon)
   + Fix unstabilizing comments on assignments (#1093) (Guillaume Petiot)
   + Internal: Make Fmt.t abstract (#1109) (Jules Aguillon)
   + Improve: give a hint when warning 50 is raised (#1111) (Guillaume Petiot)

src/Conf.ml

@@ -1709,6 +1709,12 @@ let (_profile : t option C.t) =
 
 let is_stdin = function Stdin -> true | File _ -> false
 
+let kind_of_ext fname =
+  match Filename.extension fname with
+  | ".ml" | ".mlt" -> Some `Impl
+  | ".mli" -> Some `Intf
+  | _ -> None
+
 let validate () =
   let inputs_len = List.length !inputs in
   let has_stdin = List.exists ~f:is_stdin !inputs in
@@ -1721,11 +1727,14 @@ let validate () =
     `Error (false, "Must specify at least one input file, or `-` for stdin")
   else if has_stdin && inputs_len > 1 then
     `Error (false, "Cannot specify stdin together with other inputs")
-  else if has_stdin && Option.is_none !kind then
+  else if
+    has_stdin && Option.is_none !kind
+    && Option.is_none (Option.bind ~f:kind_of_ext !name)
+  then
     `Error
       ( false
-      , "Must specify at least one of --impl, --intf or --use-file when \
-         reading from stdin" )
+      , "Must specify at least one of --name, --impl or --intf when reading \
+         from stdin" )
   else if has_stdin && !inplace then
     `Error (false, "Cannot specify stdin together with --inplace")
   else if !inplace && Option.is_some !output then
@@ -1973,13 +1982,13 @@ let kind_of file =
   match !kind with
   | Some kind -> kind
   | None -> (
-    match file with
-    | Stdin -> impossible "checked by validate"
-    | File fname -> (
-      match Filename.extension fname with
-      | ".ml" -> `Impl
-      | ".mli" -> `Intf
-      | _ -> `Impl ) )
+    match Option.bind ~f:kind_of_ext !name with
+    | Some kind -> kind
+    | None -> (
+      match file with
+      | Stdin -> impossible "checked by validate"
+      | File fname -> (
+        match kind_of_ext fname with Some kind -> kind | None -> `Impl ) ) )
 
 let name_of file =
   match !name with

test/cli/dune.inc

@@ -79,6 +79,16 @@
  (name runtest)
  (action (diff err_stdin_and_inplace.ref err_stdin_and_inplace.output)))
 
+(rule
+ (targets err_stdin_name_unknown_ext.output)
+ (action
+  (with-outputs-to %{targets}
+   (system "! %{bin:ocamlformat} %{read-lines:err_stdin_name_unknown_ext.opts} < err_stdin_name_unknown_ext.stdin"))))
+
+(alias
+ (name runtest)
+ (action (diff err_stdin_name_unknown_ext.ref err_stdin_name_unknown_ext.output)))
+
 (rule
  (targets err_stdin_no_kind.output)
  (action
@@ -89,6 +99,16 @@
  (name runtest)
  (action (diff err_stdin_no_kind.ref err_stdin_no_kind.output)))
 
+(rule
+ (targets name_unknown_ext.output)
+ (action
+  (with-outputs-to %{targets}
+   (system "%{bin:ocamlformat} %{read-lines:name_unknown_ext.opts}"))))
+
+(alias
+ (name runtest)
+ (action (diff name_unknown_ext.ref name_unknown_ext.output)))
+
 (rule
  (targets stdin_and_impl.output)
  (action
@@ -108,3 +128,13 @@
 (alias
  (name runtest)
  (action (diff stdin_and_intf.ref stdin_and_intf.output)))
+
+(rule
+ (targets stdin_and_name.output)
+ (action
+  (with-outputs-to %{targets}
+   (system "%{bin:ocamlformat} %{read-lines:stdin_and_name.opts} < stdin_and_name.stdin"))))
+
+(alias
+ (name runtest)
+ (action (diff stdin_and_name.ref stdin_and_name.output)))

test/cli/err_stdin_and_inplace.ref

@@ -1 +1 @@
-ocamlformat: Must specify at least one of --impl, --intf or --use-file when reading from stdin
+ocamlformat: Must specify at least one of --name, --impl or --intf when reading from stdin

test/cli/err_stdin_name_unknown_ext.opts

@@ -0,0 +1 @@
+--name b.cpp -

test/cli/err_stdin_name_unknown_ext.ref

@@ -0,0 +1 @@
+ocamlformat: Must specify at least one of --name, --impl or --intf when reading from stdin

test/cli/err_stdin_name_unknown_ext.stdin

@@ -0,0 +1 @@
+sample/a.ml

test/cli/err_stdin_no_kind.ref

@@ -1 +1 @@
-ocamlformat: Must specify at least one of --impl, --intf or --use-file when reading from stdin
+ocamlformat: Must specify at least one of --name, --impl or --intf when reading from stdin

test/cli/name_unknown_ext.opts

@@ -0,0 +1 @@
+--name b.cpp sample/b.ml

test/cli/name_unknown_ext.ref

@@ -0,0 +1 @@
+let () = print_endline A.x

test/cli/stdin_and_name.opts

@@ -0,0 +1 @@
+--name a.ml -

test/cli/stdin_and_name.ref

@@ -0,0 +1 @@
+let x = "Hello World"

test/cli/stdin_and_name.stdin

@@ -0,0 +1 @@
+sample/a.ml