From 5a60dff9179b556fee3a58a84b6c793f45dd484d Mon Sep 17 00:00:00 2001
From: Pierre Chambart <pierre.chambart@ocamlpro.com>
Date: Thu, 19 Jul 2018 17:46:18 +0200
Subject: [PATCH] Protocol_compiler: Add an option to avoid compiling

---
 scripts/archive_protocol.sh           |  2 +-
 scripts/update_hashes.sh              |  4 ++--
 src/lib_protocol_compiler/compiler.ml | 12 +++++++++---
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/scripts/archive_protocol.sh b/scripts/archive_protocol.sh
index 5fcc61d62..14c7d6639 100755
--- a/scripts/archive_protocol.sh
+++ b/scripts/archive_protocol.sh
@@ -36,7 +36,7 @@ echo "Computing the protocol hash..."
 
 cp src/proto_${name}/lib_protocol/src/*.ml src/proto_${name}/lib_protocol/src/*.mli "$alpha_tmpdir"/src/
 grep -v '"hash"' < src/proto_${name}/lib_protocol/src/TEZOS_PROTOCOL > "$alpha_tmpdir"/src/TEZOS_PROTOCOL
-long_hash=`./tezos-protocol-compiler $alpha_tmpdir/tmp $alpha_tmpdir/src | cut -d' ' -f2`
+long_hash=`./tezos-protocol-compiler -hash-only  $alpha_tmpdir/tmp $alpha_tmpdir/src`
 short_hash=$(echo $long_hash | head -c 8)
 
 if [ -d "src/proto_${version}_${short_hash}" ] ; then
diff --git a/scripts/update_hashes.sh b/scripts/update_hashes.sh
index bb4a732da..42f2f7da9 100755
--- a/scripts/update_hashes.sh
+++ b/scripts/update_hashes.sh
@@ -22,7 +22,7 @@ genesis_tmpdir=`mktemp -d`
 mkdir $genesis_tmpdir/src
 cp src/proto_genesis/lib_protocol/src/*.ml src/proto_genesis/lib_protocol/src/*.mli $genesis_tmpdir/src/
 grep -v '"hash"' < src/proto_genesis/lib_protocol/src/TEZOS_PROTOCOL > $genesis_tmpdir/src/TEZOS_PROTOCOL
-new_hash_genesis=`./tezos-protocol-compiler $genesis_tmpdir/tmp $genesis_tmpdir/src | cut -d' ' -f2`
+new_hash_genesis=`./tezos-protocol-compiler -hash-only $genesis_tmpdir/tmp $genesis_tmpdir/src`
 echo "Genesis's new hash: $new_hash_genesis"
 if [ "$current_hash_genesis" != "$new_hash_genesis" ]
 then
@@ -38,7 +38,7 @@ alpha_tmpdir=`mktemp -d`
 mkdir $alpha_tmpdir/src
 cp src/proto_alpha/lib_protocol/src/*.ml src/proto_alpha/lib_protocol/src/*.mli $alpha_tmpdir/src/
 grep -v '"hash"' < src/proto_alpha/lib_protocol/src/TEZOS_PROTOCOL > $alpha_tmpdir/src/TEZOS_PROTOCOL
-new_hash_alpha=`./tezos-protocol-compiler $alpha_tmpdir/tmp $alpha_tmpdir/src | cut -d' ' -f2`
+new_hash_alpha=`./tezos-protocol-compiler -hash-only $alpha_tmpdir/tmp $alpha_tmpdir/src`
 echo "Alpha's new hash: $new_hash_alpha"
 if [ "$current_hash_alpha" != "$new_hash_alpha" ]
 then
diff --git a/src/lib_protocol_compiler/compiler.ml b/src/lib_protocol_compiler/compiler.ml
index cc847745c..c98c7a90a 100644
--- a/src/lib_protocol_compiler/compiler.ml
+++ b/src/lib_protocol_compiler/compiler.ml
@@ -150,10 +150,12 @@ let main { compile_ml ; pack_objects ; link_shared } =
   and static = ref false
   and register = ref false
   and build_dir = ref None
-  and output_dep = ref false in
+  and output_dep = ref false
+  and hash_only = ref false in
   let args_spec = [
-    "-static", Arg.Set static, " Only build the static library (no .cmxs)";
-    "-register", Arg.Set register, " Generete the `Registerer` module";
+    "-hash-only", Arg.Set hash_only, " Don't compile" ;
+    "-static", Arg.Set static, " Only build the static library (no .cmxs)" ;
+    "-register", Arg.Set register, " Generete the `Registerer` module" ;
     "-bin-annot", Arg.Set Clflags.binary_annotations, " (see ocamlopt)" ;
     "-g", Arg.Set Clflags.debug, " (see ocamlopt)" ;
     "-output-dep", Arg.Set output_dep, " ..." ;
@@ -182,6 +184,10 @@ let main { compile_ml ; pack_objects ; link_shared } =
     | Error err ->
         Format.kasprintf Pervasives.failwith
           "Failed to read TEZOS_PROTOCOL: %a" pp_print_error err in
+  if !hash_only then begin
+    Format.printf "%a@." Protocol_hash.pp hash ;
+    exit 0
+  end ;
   Lwt_main.run (Lwt_utils_unix.create_dir ~perm:0o755 build_dir) ;
   Lwt_main.run (Lwt_utils_unix.create_dir ~perm:0o755 (Filename.dirname output)) ;
   (* Generate the 'functor' *)