Libguestfs - Aug 2023 - [libnbd PATCH] golang: Optionally use gofmt on generated .go files

Combine my recent work on improving the generated Go output with
Tage's work on using a canonical formatter for Rust.  If gofmt is
available during the build, then the generated .go files will now use
TAB indents and have proper columnar alignment; if it is not
available, the project still compiles.

Signed-off-by: Eric Blake <eblake at redhat.com>
---

Followup to this earlier series:
https://listman.redhat.com/archives/libguestfs/2023-July/032133.html

I still need to fold in the 'make check' verification of non-generated
.go files, plus Dan's idea of enabling CI coverage...

 configure.ac           |  1 +
 generator/config.mli   |  1 +
 generator/utils.mli    |  1 +
 generator/config.ml.in |  3 ++-
 generator/generator.ml | 15 ++++++++++-----
 generator/utils.ml     | 12 +++++++++++-
 6 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index 3e8b9142..b475dccf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -596,6 +596,7 @@ AC_ARG_ENABLE([golang],
         [enable_golang=yes])
 AS_IF([test "x$enable_golang" != "xno"],[
     AC_CHECK_PROG([GOLANG],[go],[go],[no])
+    AC_CHECK_PROG([GOFMT],[gofmt],[gofmt],[no])
     AS_IF([test "x$GOLANG" != "xno"],[
         AC_MSG_CHECKING([if $GOLANG is usable])
         AS_IF([ (
diff --git a/generator/config.mli b/generator/config.mli
index 5f1a46a6..22c61dad 100644
--- a/generator/config.mli
+++ b/generator/config.mli
@@ -17,4 +17,5 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  *)

+val gofmt : string
 val rustfmt : string
diff --git a/generator/utils.mli b/generator/utils.mli
index d97d43ac..9f7824b2 100644
--- a/generator/utils.mli
+++ b/generator/utils.mli
@@ -54,6 +54,7 @@ val

 (** Type of code formatter. *)
 type formatter +  | Gofmt
   | Rustfmt

 (** Redirect stdout to a file. Possibly formatting the code. *)
diff --git a/generator/config.ml.in b/generator/config.ml.in
index 7ac5237c..48d0d4a4 100644
--- a/generator/config.ml.in
+++ b/generator/config.ml.in
@@ -18,4 +18,5 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  *)

-let rustfmt  = "@RUSTFMT@"
+let gofmt = "@GOFMT@"
+let rustfmt = "@RUSTFMT@"
diff --git a/generator/generator.ml b/generator/generator.ml
index c62b0c4f..8c9a585b 100644
--- a/generator/generator.ml
+++ b/generator/generator.ml
@@ -57,10 +57,15 @@ let
   output_to "ocaml/NBD.ml" OCaml.generate_ocaml_nbd_ml;
   output_to "ocaml/nbd-c.c" OCaml.generate_ocaml_nbd_c;

-  output_to "golang/bindings.go" GoLang.generate_golang_bindings_go;
-  output_to "golang/closures.go" GoLang.generate_golang_closures_go;
-  output_to "golang/wrappers.go" GoLang.generate_golang_wrappers_go;
+  output_to ~formatter:(Some Gofmt) "golang/bindings.go"
+    GoLang.generate_golang_bindings_go;
+  output_to ~formatter:(Some Gofmt) "golang/closures.go"
+    GoLang.generate_golang_closures_go;
+  output_to ~formatter:(Some Gofmt) "golang/wrappers.go"
+    GoLang.generate_golang_wrappers_go;
   output_to "golang/wrappers.h" GoLang.generate_golang_wrappers_h;

-  output_to ~formatter:(Some Rustfmt)
"rust/libnbd-sys/src/generated.rs" RustSys.generate_rust_sys_bindings;
-  output_to ~formatter:(Some Rustfmt) "rust/src/bindings.rs"
Rust.generate_rust_bindings;
+  output_to ~formatter:(Some Rustfmt)
"rust/libnbd-sys/src/generated.rs"
+    RustSys.generate_rust_sys_bindings;
+  output_to ~formatter:(Some Rustfmt) "rust/src/bindings.rs"
+    Rust.generate_rust_bindings;
diff --git a/generator/utils.ml b/generator/utils.ml
index 3302b309..443ac6df 100644
--- a/generator/utils.ml
+++ b/generator/utils.ml
@@ -420,6 +420,7 @@ let
   | i -> failwithf "%s: failed with error code %d" cmd i

 type formatter +  | Gofmt
   | Rustfmt

 let output_to ?(formatter = None) filename k @@ -431,6 +432,15 @@ let
   close_out c;
   chan := NoOutput;
   (match formatter with
+  | Some Gofmt ->
+     if Config.gofmt <> "no" then (
+       let cmd = sprintf "%s -w %s" Config.gofmt filename_new in
+       match system cmd with
+       | WEXITED 0 -> ()
+       | WEXITED i -> failwithf "gofmt failed with exit code %d" i
+       | WSIGNALED i | WSTOPPED i ->
+          failwithf "gofmt was killed or stopped by signal %d" i
+     )
   | Some Rustfmt ->
      if Config.rustfmt <> "no" then (
        let cmd = sprintf "%s %s" Config.rustfmt filename_new in
@@ -439,7 +449,7 @@ let
        | WEXITED i -> failwithf "rustfmt failed with exit code %d"
i
        | WSIGNALED i | WSTOPPED i ->
           failwithf "rustfmt was killed or stopped by signal %d" i
-     );
+     )
   | None -> ());
   (* Is the new file different from the current file? *)
   if Sys.file_exists filename && files_equal filename filename_new then
-- 
2.41.0

On Fri, Aug 04, 2023 at 09:29:48AM -0500, Eric Blake
wrote:
> Combine my recent work on improving the generated Go output with
> Tage's work on using a canonical formatter for Rust.  If gofmt is
> available during the build, then the generated .go files will now use
> TAB indents and have proper columnar alignment; if it is not
> available, the project still compiles.
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---
> 
> Followup to this earlier series:
> https://listman.redhat.com/archives/libguestfs/2023-July/032133.html
Now in as 9cb10b39, after rebasing to yet more rustfmt changes in the meantime.
> 
> I still need to fold in the 'make check' verification of
non-generated
> .go files, plus Dan's idea of enabling CI coverage...
This still remains on my todo list.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org