Support passing arguments to run_binary via param file

Allows to use run_binary in the case when the size of the command line
can grow longer than the maximum size allowed by the system.

Author: vejbomar

docs/run_binary_doc.md

@@ -11,7 +11,7 @@ Runs a binary as a build action. This rule does not require Bash (unlike native.
 ## run_binary
 
 <pre>
-run_binary(<a href="#run_binary-name">name</a>, <a href="#run_binary-args">args</a>, <a href="#run_binary-env">env</a>, <a href="#run_binary-outs">outs</a>, <a href="#run_binary-srcs">srcs</a>, <a href="#run_binary-tool">tool</a>)
+run_binary(<a href="#run_binary-name">name</a>, <a href="#run_binary-args">args</a>, <a href="#run_binary-env">env</a>, <a href="#run_binary-outs">outs</a>, <a href="#run_binary-param_file_format">param_file_format</a>, <a href="#run_binary-srcs">srcs</a>, <a href="#run_binary-tool">tool</a>)
 </pre>
 
 Runs a binary as a build action.
@@ -27,6 +27,7 @@ This rule does not require Bash (unlike `native.genrule`).
 | <a id="run_binary-args"></a>args |  Command line arguments of the binary.<br><br>Subject to [<code>$(location)</code>](https://bazel.build/reference/be/make-variables#predefined_label_variables) expansion.   | List of strings | optional | <code>[]</code> |
 | <a id="run_binary-env"></a>env |  Environment variables of the action.<br><br>Subject to  [<code>$(location)</code>](https://bazel.build/reference/be/make-variables#predefined_label_variables) expansion.   | <a href="https://bazel.build/rules/lib/dict">Dictionary: String -> String</a> | optional | <code>{}</code> |
 | <a id="run_binary-outs"></a>outs |  Output files generated by the action.<br><br>These labels are available for <code>$(location)</code> expansion in <code>args</code> and <code>env</code>.   | List of labels | required |  |
+| <a id="run_binary-param_file_format"></a>param_file_format |  If provided, Bazel can pass command-line arguments to the tool via file.<br><br>Should be used when the size of the command line can grow longer than the maximum size allowed by the system. The format is the same as the format of <code>param_file_arg</code> in [<code>Args.param_file_arg</code>](https://bazel.build/rules/lib/builtins/Args#use_param_file). The <code>tool</code> has to support reading arguments from the file for this to work.   | String | optional | <code>""</code> |
 | <a id="run_binary-srcs"></a>srcs |  Additional inputs of the action.<br><br>These labels are available for <code>$(location)</code> expansion in <code>args</code> and <code>env</code>.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="run_binary-tool"></a>tool |  The tool to run in the action.<br><br>Must be the label of a *_binary rule, of a rule that generates an executable file, or of a file that can be executed as a subprocess (e.g. an .exe or .bat file on Windows or a binary with executable permission on Linux). This label is available for <code>$(location)</code> expansion in <code>args</code> and <code>env</code>.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 

rules/run_binary.bzl

@@ -22,7 +22,13 @@ load("//lib:dicts.bzl", "dicts")
 
 def _impl(ctx):
     tool_as_list = [ctx.attr.tool]
-    args = [
+
+    args = ctx.actions.args()
+    if ctx.attr.param_file_format != "":
+        args.set_param_file_format("multiline")
+        args.use_param_file(param_file_arg = ctx.attr.param_file_format, use_always = False)
+
+    for arg in ctx.attr.args:
         # Expand $(location) / $(locations) in args.
         #
         # To keep the rule simple, do not expand Make Variables (like *_binary.args usually would).
@@ -33,9 +39,8 @@ def _impl(ctx):
         # tokenization they would have to write args=["'a b'"] or args=["a\\ b"]. There's no
         # documented tokenization function anyway (as of 2019-05-21 ctx.tokenize exists but is
         # undocumented, see https://github.com/bazelbuild/bazel/issues/8389).
-        ctx.expand_location(a, tool_as_list) if "$(location" in a else a
-        for a in ctx.attr.args
-    ]
+        args.add(ctx.expand_location(arg, tool_as_list) if "$(location" in arg else arg)
+
     envs = {
         # Expand $(location) / $(locations) in the values.
         k: ctx.expand_location(v, tool_as_list) if "$(location" in v else v
@@ -46,7 +51,7 @@ def _impl(ctx):
         inputs = ctx.files.srcs,
         tools = [ctx.executable.tool],
         executable = ctx.executable.tool,
-        arguments = args,
+        arguments = [args],
         mnemonic = "RunBinary",
         use_default_shell_env = False,
         env = dicts.add(ctx.configuration.default_shell_env, envs),
@@ -92,5 +97,13 @@ run_binary = rule(
                   " [`$(location)`](https://bazel.build/reference/be/make-variables#predefined_label_variables)" +
                   " expansion.",
         ),
+        "param_file_format": attr.string(
+            doc = "If provided, Bazel can pass command-line arguments to the tool via file.\n\n" +
+                  "Should be used when the size of the command line can grow longer than the " +
+                  "maximum size allowed by the system. The format is the same as the format of " +
+                  "`param_file_arg` in [`Args.param_file_arg`](https://bazel.build/rules/lib/builtins/Args#use_param_file). " +
+                  "The `tool` has to support reading arguments from the file for this to work.",
+            default = "",
+        ),
     },
 )