feat: Enable some path-mapping support in common rules (#1217)

Author: dzbarsky

lib/private/copy_common.bzl

@@ -11,4 +11,5 @@ COPY_EXECUTION_REQUIREMENTS = {
     # Sandboxing for this action is wasteful since there is a 1:1 mapping of input file/directory to
     # output file/directory so little room for non-hermetic inputs to sneak in to the execution.
     "no-sandbox": "1",
+    "supports-path-mapping": "1",
 }

lib/private/copy_directory.bzl

@@ -43,26 +43,25 @@ def copy_directory_bin_action(
             See the caveats above about interactions with remote execution and caching.
 
     """
-    args = [
-        src.path,
-        dst.path,
-    ]
+    args = ctx.actions.args()
+    args.add_all([src, dst], expand_directories = False)
+
     if verbose:
-        args.append("--verbose")
+        args.add("--verbose")
 
     if hardlink == "on":
-        args.append("--hardlink")
+        args.add("--hardlink")
     elif hardlink == "auto" and not src.is_source:
-        args.append("--hardlink")
+        args.add("--hardlink")
 
     if preserve_mtime:
-        args.append("--preserve-mtime")
+        args.add("--preserve-mtime")
 
     ctx.actions.run(
         inputs = [src],
         outputs = [dst],
         executable = copy_directory_bin,
-        arguments = args,
+        arguments = [args],
         # TODO: Drop this after https://github.com/bazel-contrib/bazel-lib/issues/1146
         env = {"GODEBUG": "winsymlink=0"},
         mnemonic = "CopyDirectory",

lib/private/copy_file.bzl

@@ -68,18 +68,47 @@ def copy_file_action(ctx, src, dst, dir_path = None):
 
     if dst.is_directory:
         fail("dst must not be a TreeArtifact")
+
+    args = ctx.actions.args()
+    args.add("cp")
+
     if src.is_directory:
         if not dir_path:
             fail("dir_path must be set if src is a TreeArtifact")
-        src_path = "/".join([src.path, dir_path])
+
+        # TODO(zbarsky): No path-mapping here, _copy_file_from_directory can support it though.
+        # We can consider exposing it later.
+        args.add("/".join([src.path, dir_path]))
     else:
-        src_path = src.path
+        args.add(src)
+
+    args.add(dst)
+    _run_copy_file_action(ctx, src, dst, args)
+
+def _directory_path(src):
+    dir = src[DirectoryPathInfo].directory
+    dir_path = src[DirectoryPathInfo].path
+    if not dir_path:
+        fail("dir_path must be set if src is a TreeArtifact")
+
+    return "/".join([dir.path, dir_path])
 
+def _copy_file_from_directory(ctx, src, dst):
+    if dst.is_directory:
+        fail("dst must not be a TreeArtifact")
+
+    args = ctx.actions.args()
+    args.add("cp")
+    args.add_all([src], map_each = _directory_path)
+    args.add(dst)
+    _run_copy_file_action(ctx, src[DirectoryPathInfo].directory, dst, args)
+
+def _run_copy_file_action(ctx, src, dst, args):
     coreutils = ctx.toolchains[_COREUTILS_TOOLCHAIN].coreutils_info
 
     ctx.actions.run(
         executable = coreutils.bin,
-        arguments = ["cp", src_path, dst.path],
+        arguments = [args],
         inputs = [src],
         outputs = [dst],
         mnemonic = "CopyFile",
@@ -100,12 +129,7 @@ def _copy_file_impl(ctx):
             is_executable = ctx.attr.is_executable,
         )
     elif DirectoryPathInfo in ctx.attr.src:
-        copy_file_action(
-            ctx,
-            ctx.attr.src[DirectoryPathInfo].directory,
-            ctx.outputs.out,
-            dir_path = ctx.attr.src[DirectoryPathInfo].path,
-        )
+        _copy_file_from_directory(ctx, ctx.attr.src, ctx.outputs.out)
     else:
         if len(ctx.files.src) != 1:
             fail("src must be a single file or a target that provides a DirectoryPathInfo")

lib/private/copy_to_directory.bzl

@@ -505,11 +505,18 @@ def copy_to_directory_bin_action(
         content = json.encode_indent(config),
     )
 
+    args = ctx.actions.args()
+    args.add(config_file)
+    args.add(ctx.label.workspace_name)
+
+    # TODO(zbarsky): We path-map this action but the config's content will still mismatch.
+    # Needs a more holistic fix there.
+
     ctx.actions.run(
         inputs = file_inputs + [config_file],
         outputs = [dst],
         executable = copy_to_directory_bin,
-        arguments = [config_file.path, ctx.label.workspace_name],
+        arguments = [args],
         # TODO: Drop this after https://github.com/bazel-contrib/bazel-lib/issues/1146
         env = {"GODEBUG": "winsymlink=0"},
         mnemonic = "CopyToDirectory",

lib/private/expand_template.bzl

@@ -50,6 +50,7 @@ def _expand_template_impl(ctx):
             inputs = inputs,
             executable = expand_template_info.bin,
             toolchain = "@bazel_lib//lib:expand_template_toolchain_type",
+            execution_requirements = {"supports-path-mapping": "1"},
         )
     else:
         ctx.actions.expand_template(

lib/private/run_binary.bzl

@@ -70,7 +70,8 @@ Possible fixes:
         resource_set = resource_set(ctx.attr),
         mnemonic = ctx.attr.mnemonic if ctx.attr.mnemonic else None,
         progress_message = ctx.attr.progress_message if ctx.attr.progress_message else None,
-        execution_requirements = ctx.attr.execution_requirements if ctx.attr.execution_requirements else None,
+        # Target can override if they want to.
+        execution_requirements = dicts.add({"supports-path-mapping": "1"}, ctx.attr.execution_requirements),
         use_default_shell_env = ctx.attr.use_default_shell_env,
         env = dicts.add(ctx.configuration.default_shell_env, envs),
     )