Use runfiles wrapper

sh/private/defs.bzl

@@ -31,12 +31,11 @@ def mk_template_variable_info(name, sh_binaries_info):
         },
     ))
 
-def mk_default_info_with_files_to_run(ctx, name, files, runfiles):
+def mk_default_info_with_files_to_run(ctx, executable, files, runfiles):
     # Create a dummy executable to trigger the generation of a FilesToRun
     # provider which can be used in custom rules depending on this bundle to
     # input the needed runfiles into build actions.
     # This is a workaround for https://github.com/bazelbuild/bazel/issues/15486
-    executable = ctx.actions.declare_file(name)
     ctx.actions.write(executable, "", is_executable = True)
     return DefaultInfo(
         executable = executable,

sh/sh.bzl

@@ -17,7 +17,33 @@ ShBinariesInfo = provider(
 
 _WINDOWS_EXE_EXTENSIONS = [".exe", ".cmd", ".bat", ".ps1"]
 
-def _sh_binaries_from_srcs(ctx, srcs, is_windows):
+_POSIX_WRAPPER_TEMPLATE = """\
+#!/bin/sh
+if [[ -f "{main_executable}.runfiles_manifest" ]]; then
+  export RUNFILES_MANIFEST_FILE="{main_executable}.runfiles_manifest"
+elif [[ -d "{main_executable}.runfiles" ]]; then
+  export RUNFILES_DIR="{main_executable}.runfiles"
+else
+  echo "ERROR: Runfiles not found for bundle {main_executable}" >&2
+  exit 1
+fi
+exec "{original_executable}" "$@"
+"""
+
+_WINDOWS_WRAPPER_TEMPLATE = """\
+@echo off
+if exist "{main_executable}.runfiles_manifest" (
+  set RUNFILES_MANIFEST_FILE={main_executable}.runfiles_manifest
+) else if exist "{main_executable}.runfiles" (
+  set RUNFILES_DIR={main_executable}.runfiles
+) else (
+  echo ERROR: Runfiles not found for bundle {main_executable} >&2
+  exit /b 1
+)
+"{original_executable}" %*
+"""
+
+def _sh_binaries_from_srcs(ctx, srcs, is_windows, main_executable):
     executable_files = []
     runfiles = ctx.runfiles()
     executables_dict = dict()
@@ -27,10 +53,10 @@ def _sh_binaries_from_srcs(ctx, srcs, is_windows):
         if src[DefaultInfo].files_to_run == None or src[DefaultInfo].files_to_run.executable == None:
             fail("srcs must be executable, but '{}' is not.".format(src.label))
 
-        executable = src[DefaultInfo].files_to_run.executable
-        name = executable.basename
+        original_executable = src[DefaultInfo].files_to_run.executable
+        name = original_executable.basename
         if is_windows:
-            (noext, ext) = paths.split_extension(executable.basename)
+            (noext, ext) = paths.split_extension(original_executable.basename)
             if ext in _WINDOWS_EXE_EXTENSIONS:
                 name = noext
 
@@ -41,8 +67,21 @@ def _sh_binaries_from_srcs(ctx, srcs, is_windows):
                 src.label,
             ))
 
+        if src[DefaultInfo].default_runfiles:
+            executable = ctx.actions.declare_file(ctx.label.name + ".path/" + (name + ".bat" if is_windows else name))
+            ctx.actions.write(
+                executable,
+                (_WINDOWS_WRAPPER_TEMPLATE if is_windows else _POSIX_WRAPPER_TEMPLATE).format(
+                    main_executable = main_executable.path,
+                    original_executable = original_executable.path,
+                ),
+                is_executable = True,
+            )
+            executable_files.append(original_executable)
+            runfiles = runfiles.merge(src[DefaultInfo].default_runfiles)
+        else:
+            executable = original_executable
         executable_files.append(executable)
-        runfiles = runfiles.merge(src[DefaultInfo].default_runfiles)
         executables_dict[name] = executable
         executable_paths.append(executable.dirname)
 
@@ -101,15 +140,16 @@ def _mk_sh_binaries_info(direct, transitive):
 
 def _sh_binaries_impl(ctx):
     is_windows = ctx.attr._is_windows[ConstantInfo].value
-    direct = _sh_binaries_from_srcs(ctx, ctx.attr.srcs, is_windows)
+    executable = ctx.actions.declare_file(ctx.label.name)
+    direct = _sh_binaries_from_srcs(ctx, ctx.attr.srcs, is_windows, executable)
     transitive = _sh_binaries_from_deps(ctx, ctx.attr.deps)
     data_runfiles = _runfiles_from_data(ctx, ctx.attr.data)
 
     sh_binaries_info = _mk_sh_binaries_info(direct, transitive)
     template_variable_info = mk_template_variable_info(ctx.label.name, sh_binaries_info)
     default_info = mk_default_info_with_files_to_run(
         ctx,
-        ctx.label.name,
+        executable,
         depset(direct = direct.executable_files, transitive = transitive.executable_files),
         direct.runfiles.merge(transitive.runfiles).merge(data_runfiles),
     )