Inject a source identifer into moc (#1631)

I have been preaching this for so long to other teams, I really better
clean up my own backyard: Make sure that you can run

    moc --version

and get a somewhat useful indication what version that is. This is
important for when random people use `moc` from random versions of SDK
or – later – build it themselves and then provide bug reports.

When building locally, with `.git` around, this now injects the git
revision:

    $ ./moc --version
    Motoko compiler (revision 9abae15e-dirty)

(the `-dirty` indicates that my work-tree is not clean).

When `.git` is _not_ available, as typically (and rightfully) when
building with nix, it looks if Nix’s `$out` variable is set, and
includes that:

    $ $(nix-build -A moc)/bin/moc --version
    Motoko compiler (revision 3yrjbw6g-aqppc05d-596yiq8k-bsznw5jw)

This is less useful for end-users, but it still allows us to (hopefully)
identify the version, in the worst case by running this command on all
revisions to find the right one:

    $ nix-store --query --outputs $(nix-instantiate -A moc-bin)
    /nix/store/3yrjbw6gaqppc05d596yiq8kbsznw5jw-moc-bin

Note that I injected dashes into the id so that it does not trip up 
`common.lib.standaloneRust` which otherwise would take it for an
unwanted dependency.

@basvandijk suggests in
dfinity/sdk#383 (comment) that one
may query Hydra’s database to map from id to revision.

Once we do versioned releases, we can of course extend this to inject
the version number there, and use `git describe --tag` to have
`v1.0-200-9abae15e` like descriptions.

I _hope_ this will not cause extra recompilations with `dune`, and will
work out-of-the box for everyone, but we’ll see.

default.nix

@@ -89,6 +89,7 @@ let ocaml_exe = name: bin:
       buildInputs = commonBuildInputs staticpkgs;
 
       buildPhase = ''
+        patchShebangs .
         make DUNE_OPTS="--display=short --profile ${profile}" ${bin}
       '';
 
@@ -312,6 +313,7 @@ rec {
           nixpkgs.nodejs-10_x
         ];
         buildPhase = ''
+          patchShebangs .
           make ${n}.js
         '';
         installPhase = ''

src/Makefile

@@ -17,9 +17,12 @@ ALL_TARGETS = $(MO_IDE_TARGET) $(MO_LD_TARGET) $(MO_DOC_TARGET) $(MOC_TARGET) $(
 
 .PHONY: all clean moc mo-doc mo-ide mo-ld moc.js didc deser unit-tests didc.js
 
+# let make update check this file every time
+SOURCE_ID = source_id/source_id.ml
+
 # This targets is spelled out so that `make`
 # only invokes `dune` once, much faster
-all: grammar
+all: $(SOURCE_ID) grammar
 	dune build $(DUNE_OPTS) $(ALL_TARGETS)
 	@ln -fs $(MOC_TARGET) moc
 	@ln -fs $(MO_IDE_TARGET) mo-ide
@@ -28,47 +31,58 @@ all: grammar
 	@ln -fs $(MOC_JS_TARGET) moc.js
 	@ln -fs $(DIDC_TARGET) didc
 	@ln -fs $(DESER_TARGET) deser
+	@ln -fs $(DIDC_JS_TARGET) didc.js
 
-moc:
+moc: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(MOC_TARGET)
 	@ln -fs $(MOC_TARGET) moc
 
-mo-ide:
+mo-ide: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(MO_IDE_TARGET)
 	@ln -fs $(MO_IDE_TARGET) mo-ide
 
-mo-ld:
+mo-ld: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(MO_LD_TARGET)
 	@ln -fs $(MO_LD_TARGET) mo-ld
 
-mo-doc:
+mo-doc: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(MO_DOC_TARGET)
 	@ln -fs $(MO_DOC_TARGET) mo-doc
 
-moc.js:
+moc.js: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(MOC_JS_TARGET)
 	@ln -fs $(MOC_JS_TARGET) moc.js
 
-didc.js:
+didc.js: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(DIDC_JS_TARGET)
 	@ln -fs $(DIDC_JS_TARGET) didc.js
 
-didc:
+didc: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(DIDC_TARGET)
 	@ln -fs $(DIDC_TARGET) didc
 
-deser:
+deser: $(SOURCE_ID)
 	dune build $(DUNE_OPTS) $(DESER_TARGET)
 	@ln -fs $(DESER_TARGET) deser
 
+.PHONY: $(SOURCE_ID)
+
+# only actually touch the file if changed
+$(SOURCE_ID):
+	source_id/gen.sh
+
 unit-tests:
 	dune runtest $(DUNE_OPTS)
 
 format:
-	ocamlformat --inplace docs/*.mli docs/*.ml languageServer/*.ml languageServer/*.mli
+	ocamlformat --inplace \
+	  docs/*.mli \
+          docs/*.ml \
+          languageServer/*.ml \
+          languageServer/*.mli
 
 clean:
-	rm -f moc mo-ide mo-ld moc.js didc deser
+	rm -f moc mo-ide mo-ld moc.js didc deser $(SOURCE_ID)
 	dune clean
 
 test: $(NAME)
@@ -78,7 +92,6 @@ test: $(NAME)
 test-quick: $(NAME)
 	make -C ../test MOC=$(MOC) quick
 
-
 grammar: ../doc/modules/language-guide/examples/grammar.txt
 
 ../doc/modules/language-guide/examples/grammar.txt: mo_frontend/parser.mly gen-grammar/gen-grammar.sh gen-grammar/grammar.sed

src/exes/deser.ml

@@ -491,8 +491,7 @@ end
 (* CLI *)
 
 let name = "deser"
-let version = "0.1"
-let banner = "Interface Description Language (IDL) " ^ version ^ " message dumper"
+let banner = "Candid toolkit (revision " ^ Source_id.id ^ ")"
 let usage = "Usage: " ^ name ^ " [option] [file ...]"
 
 let mode = ref Nary

src/exes/didc.ml

@@ -2,8 +2,7 @@ open Idllib
 open Printf
 
 let name = "didc"
-let version = "0.1"
-let banner = "Interface Description Language (IDL) " ^ version ^ " interpreter"
+let banner = "Candid compiler (revision " ^ Source_id.id ^ ")"
 let usage = "Usage: " ^ name ^ " [option] [file ...]"
 
 

src/exes/dune

@@ -1,7 +1,7 @@
 (executable
  (name moc)
  (modules moc)
- (libraries profiler pipeline)
+ (libraries profiler pipeline source_id)
 )
 (executable
  (name mo_ide)
@@ -21,10 +21,10 @@
 (executable
  (name didc)
  (modules didc)
- (libraries idllib)
+ (libraries idllib source_id)
 )
 (executable
  (name deser)
  (modules deser)
- (libraries stdio num)
+ (libraries stdio num source_id)
 )

src/exes/moc.ml

@@ -4,8 +4,7 @@ open Mo_config
 open Printf
 
 let name = "moc"
-let version = "0.1"
-let banner = "Motoko " ^ version ^ " interpreter"
+let banner = "Motoko compiler (revision " ^ Source_id.id ^ ")"
 let usage = "Usage: " ^ name ^ " [option] [file ...]"
 
 

src/source_id/.gitignore

@@ -0,0 +1 @@
+source_id.ml

src/source_id/dune

@@ -0,0 +1 @@
+(library (name source_id))

src/source_id/gen.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+cd "$(dirname "$BASH_SOURCE")"
+
+file="source_id.ml"
+
+if [ "$(git rev-parse --is-inside-work-tree 2>/dev/null)" = true ]
+then echo "let id = \"$(git describe --always --dirty)\"" > $file.tmp
+elif [ -n "$out" ]
+then echo "let id = \"$(echo $out|cut -d/ -f4|cut -d- -f1|fold -w8 | paste -sd'-' -)\"" > $file.tmp
+else echo "let id = \"unidentified version\"" > $file.tmp
+fi
+if [ ! -e $file ] || ! cmp -s $file.tmp $file
+then mv $file.tmp $file
+else rm -f $file.tmp
+fi
+
+

test/repl/ok/double-import.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 -- Parsing stdin:
 > -- Parsing lib/empty.mo:
 -- Checking empty.mo:

test/repl/ok/file-and-repl.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 -- Parsing /dev/fd/63:
 -- Checking /dev/fd/63:
 -- Definedness /dev/fd/63:

test/repl/ok/outrange-int-nat.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 > let Prim : module {...}
 > +127 : Int8
 > prim:___: execution error, numeric overflow

test/repl/ok/stateful.stdout.ok

@@ -1,3 +1,3 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 > let x : Nat = 42
 > > > > 

test/repl/ok/triangle-import.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 -- Parsing stdin:
 > -- Parsing lib/b.mo:
 -- Parsing lib/c.mo:

test/repl/ok/type-lub-repl.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 > [null, ?42, ?(-25)] : [(?Int)]
 > [null, null] : [Null]
 > [{a = 42}, {b = 42}] : [{}]

test/repl/ok/variant-shorthand.stdout.ok

@@ -1,4 +1,4 @@
-Motoko 0.1 interpreter
+Motoko compiler (revision XXX)
 > #bar : {#bar}
 > #foo(#bar) : {#foo : {#bar}}
 > [#Monday, #Tuesday, #Wednesday, #Thursday, #Friday, #Saturday, #Sunday] : [{#Friday; #Monday; #Saturday; #Sunday; #Thursday; #Tuesday; #Wednesday}]

test/run.sh

@@ -88,6 +88,7 @@ function normalize () {
     sed 's/trap at 0x[a-f0-9]*/trap at 0x___:/g' |
     sed 's/source location: @[a-f0-9]*/source location: @___:/g' |
     sed 's/Ignore Diff:.*/Ignore Diff: (ignored)/ig' |
+    sed 's/compiler (revision .*)/compiler (revision XXX)/ig' |
     cat > $1.norm
     mv $1.norm $1
   fi