Add libs and extra_args attributes to the plt rule

libs are placed on the code path for erlang when the dialyzer command
is run
This turns out to be useful with elixir, which needs to be on the code
path to generate a plt from beam built with elixir

extra_args are just extra args to be passed to the `dialyzer` command

Author: HoloRin

dialyze.bzl

@@ -4,16 +4,24 @@ load(
 )
 load(
     "//private:plt.bzl",
-    _DEFAULT_PLT_APPS = "DEFAULT_PLT_APPS",
     _plt = "plt",
 )
 
-DEFAULT_PLT_APPS = _DEFAULT_PLT_APPS
+DEFAULT_PLT_APPS = ["erts", "kernel", "stdlib"]
 
 DIALYZE_TAG = "dialyze"
 
-def plt(**kwargs):
-    _plt(**kwargs)
+def plt(
+        for_target = None,
+        apps = None,
+        **kwargs):
+    if for_target == None and apps == None:
+        apps = DEFAULT_PLT_APPS
+    _plt(
+        for_target = for_target,
+        apps = apps,
+        **kwargs
+    )
 
 def dialyze(
         name = "dialyze",

private/erlang_bytecode2.bzl

@@ -41,17 +41,14 @@ def _impl(ctx):
         dir = erl_libs_dir,
     )
 
-    # it would be nice to properly compute the path, but ctx.bin_dir.path
-    # does not appear to be the whole prefix
+    erl_libs_path = ""
     if len(erl_libs_files) > 0:
-        (output_dir, _, path) = erl_libs_files[0].path.partition(erl_libs_dir)
-        if output_dir == "":
-            fail("Could not compute the ERL_LIBS relative path from {}".format(
-                erl_libs_files[0].path,
-            ))
-        erl_libs_path = path_join(output_dir.rstrip("/"), erl_libs_dir)
-    else:
-        erl_libs_path = ""
+        erl_libs_path = path_join(
+            ctx.bin_dir.path,
+            ctx.label.workspace_root,
+            ctx.label.package,
+            erl_libs_dir,
+        )
 
     out_dirs = unique_dirnames(outputs)
     if len(out_dirs) > 1:

private/plt.bzl

@@ -1,47 +1,82 @@
 load("//:erlang_app_info.bzl", "ErlangAppInfo", "flat_deps")
-load(":erlang_bytecode.bzl", "unique_dirnames")
+load("//:util.bzl", "path_join")
+load(":util.bzl", "erl_libs_contents2")
 load(
     "//tools:erlang_toolchain.bzl",
     "erlang_dirs",
     "maybe_install_erlang",
 )
 
-DEFAULT_PLT_APPS = ["erts", "kernel", "stdlib"]
-
 def _impl(ctx):
     logfile = ctx.actions.declare_file(ctx.outputs.plt.basename + ".log")
     home_dir = ctx.actions.declare_directory(ctx.label.name + "_home")
 
+    erl_libs_dir = ctx.label.name + "_deps"
+
+    erl_libs_files = erl_libs_contents2(
+        ctx,
+        deps = ctx.attr.libs,
+        dir = erl_libs_dir,
+    )
+
+    erl_libs_path = ""
+    if len(erl_libs_files) > 0:
+        erl_libs_path = path_join(
+            ctx.bin_dir.path,
+            ctx.label.workspace_root,
+            ctx.label.package,
+            erl_libs_dir,
+        )
+
+    target_files_dir = ctx.label.name + "_files"
+
+    deps = []
+    if ctx.attr.for_target != None:
+        deps.extend(flat_deps(ctx.attr.for_target[ErlangAppInfo].deps + ctx.attr.deps))
+    else:
+        deps.extend(flat_deps(ctx.attr.deps))
+
+    target_files = erl_libs_contents2(
+        ctx,
+        deps = deps,
+        dir = target_files_dir,
+    )
+
+    target_files_path = ""
+    if len(target_files) > 0:
+        target_files_path = path_join(
+            ctx.bin_dir.path,
+            ctx.label.workspace_root,
+            ctx.label.package,
+            target_files_dir,
+        )
+
+    args = ctx.actions.args()
+
     if ctx.file.plt == None:
-        source_plt_arg = "--build_plt"
+        args.add("--build_plt")
     else:
-        source_plt_arg = "--plt " + ctx.file.plt.path + " --no_check_plt --add_to_plt"
+        args.add("--plt")
+        args.add(ctx.file.plt)
+        args.add("--no_check_plt")
+        args.add("--add_to_plt")
 
     apps = []
+    apps.extend(ctx.attr.apps)
     if ctx.attr.for_target != None:
         apps.extend(ctx.attr.for_target[ErlangAppInfo].extra_apps)
-    if ctx.attr.for_target == None or ctx.attr.apps != DEFAULT_PLT_APPS:
-        apps.extend(ctx.attr.apps)
-    apps_args = ""
     if len(apps) > 0:
-        apps_args = "--apps " + " ".join(apps)
+        args.add("--apps")
+        args.add_all(apps)
 
-    deps = []
-    if ctx.attr.for_target != None:
-        deps.extend(flat_deps(ctx.attr.for_target[ErlangAppInfo].deps + ctx.attr.deps))
-    else:
-        deps.extend(flat_deps(ctx.attr.deps))
+    if target_files_path != "":
+        args.add("-r")
+        args.add(target_files_path)
 
-    files = []
-    for dep in deps:
-        lib_info = dep[ErlangAppInfo]
-        files.extend(lib_info.beam)
+    args.add_all(ctx.attr.extra_args)
 
-    dirs = unique_dirnames(files)
-    dirs_args = "".join([
-        "\n    {} \\".format(d)
-        for d in dirs
-    ])
+    args.add("--output_plt")
+    args.add(ctx.outputs.plt)
 
     (erlang_home, _, runfiles) = erlang_dirs(ctx)
 
@@ -52,38 +87,38 @@ def _impl(ctx):
 # without HOME being set, dialyzer will error regarding a default plt
 export HOME={home}
 
+if [ -n "{erl_libs_path}" ]; then
+    export ERL_LIBS={erl_libs_path}
+fi
+
 set +e
 set -x
-"{erlang_home}"/bin/dialyzer {apps_args} \\
-    {source_plt_arg} \\{dirs_args}
-    --output_plt {output} > {logfile}
+"{erlang_home}"/bin/dialyzer $@ > {logfile}
 R=$?
 set +x
 set -e
 if [ ! $R -eq 0 ]; then
-    cat {logfile}
+    head {logfile}
 fi
 exit $R
 """.format(
         maybe_install_erlang = maybe_install_erlang(ctx),
         erlang_home = erlang_home,
         home = home_dir.path,
-        apps_args = apps_args,
-        source_plt_arg = source_plt_arg,
-        dirs_args = dirs_args,
-        output = ctx.outputs.plt.path,
+        erl_libs_path = erl_libs_path,
         logfile = logfile.path,
     )
 
     inputs = depset(
-        direct = ctx.files.plt + files,
+        direct = ctx.files.plt + erl_libs_files + target_files,
         transitive = [runfiles.files],
     )
 
     ctx.actions.run_shell(
         inputs = inputs,
         outputs = [ctx.outputs.plt, logfile, home_dir],
         command = script,
+        arguments = [args],
         mnemonic = "DIALYZER",
     )
 
@@ -93,8 +128,10 @@ plt = rule(
         "plt": attr.label(
             allow_single_file = [".plt"],
         ),
-        "apps": attr.string_list(
-            default = DEFAULT_PLT_APPS,
+        "apps": attr.string_list(),
+        "extra_args": attr.string_list(),
+        "libs": attr.label_list(
+            providers = [ErlangAppInfo],
         ),
         "deps": attr.label_list(
             providers = [ErlangAppInfo],

private/util.bzl

@@ -21,7 +21,12 @@ def additional_file_dest_relative_path(dep_label, f):
     else:
         return f.short_path
 
-def erl_libs_contents2(ctx, target_info = None, deps = [], headers = False, dir = _DEFAULT_ERL_LIBS_DIR):
+def erl_libs_contents2(
+        ctx,
+        target_info = None,
+        deps = [],
+        headers = False,
+        dir = _DEFAULT_ERL_LIBS_DIR):
     erl_libs_files = []
     if headers and target_info != None:
         dep_path = path_join(dir, target_info.app_name)