Replace Targets and lists of files in `rust_toolchain` with depsets (#1109)

* Replace lists of files and Targets in `rust_toolchain` with depsets

* Use `find_sysroot` helper.

* Simply use `rust_std` files directly

* Revert "Use `find_sysroot` helper."

This reverts commit 914d159f077404568270dc57dfb3edabba3eab16.

* files

cargo/cargo_build_script.bzl

diff --git a/cargo/cargo_build_script.bzl b/cargo/cargo_build_script.bzl
index 8949173..688fe31 100644
--- a/cargo/cargo_build_script.bzl
+++ b/cargo/cargo_build_script.bzl
@@ -57,8 +57,8 @@
 
     toolchain_tools = [
         # Needed for rustc to function.
-        toolchain.rustc_lib.files,
-        toolchain.rust_std.files,
+        toolchain.rustc_lib,
+        toolchain.rust_std,
     ]
 
     cc_toolchain = find_cpp_toolchain(ctx)

rust/private/rustc.bzl

diff --git a/rust/private/rustc.bzl b/rust/private/rustc.bzl
index 260bb7b..3e2f38e 100644
--- a/rust/private/rustc.bzl
+++ b/rust/private/rustc.bzl
@@ -413,8 +413,8 @@
         ([toolchain.target_json] if toolchain.target_json else []) +
         ([] if linker_script == None else [linker_script]),
         transitive = [
-            toolchain.rustc_lib.files,
-            toolchain.rust_std.files,
+            toolchain.rustc_lib,
+            toolchain.rust_std,
             linker_depset,
             crate_info.srcs,
             dep_info.transitive_crate_outputs,
@@ -622,7 +622,7 @@
         rustc_flags.add(linker_script.path, format = "--codegen=link-arg=-T%s")
 
     # Gets the paths to the folders containing the standard library (or libcore)
-    rust_std_paths = depset([file.dirname for file in toolchain.rust_std.files.to_list()]).to_list()
+    rust_std_paths = depset([file.dirname for file in toolchain.rust_std.to_list()]).to_list()
 
     # Tell Rustc where to find the standard library
     rustc_flags.add_all(rust_std_paths, before_each = "-L", format_each = "%s")
@@ -680,7 +680,7 @@
     ))
 
     # Set the SYSROOT to the directory of the rust_std files passed to the toolchain
-    env["SYSROOT"] = paths.dirname(toolchain.rust_std.files.to_list()[0].short_path)
+    env["SYSROOT"] = paths.dirname(toolchain.rust_std.to_list()[0].short_path)
 
     # extra_rustc_flags apply to the target configuration, not the exec configuration.
     if hasattr(ctx.attr, "_extra_rustc_flags") and not is_exec_configuration(ctx):

rust/private/toolchain_utils.bzl

diff --git a/rust/private/toolchain_utils.bzl b/rust/private/toolchain_utils.bzl
index 9e011be..6b8b315 100644
--- a/rust/private/toolchain_utils.bzl
+++ b/rust/private/toolchain_utils.bzl
@@ -9,7 +9,7 @@
     Returns:
         str: A path assignable as `SYSROOT` for an action.
     """
-    sysroot_anchor = rust_toolchain.rust_std.files.to_list()[0]
+    sysroot_anchor = rust_toolchain.rust_std.to_list()[0]
     directory = sysroot_anchor.path.split(sysroot_anchor.short_path, 1)[0]
     return directory.rstrip("/")
 
@@ -24,7 +24,7 @@
                 toolchain.cargo,
                 toolchain.rustc,
             ],
-            transitive_files = toolchain.rustc_lib.files,
+            transitive_files = toolchain.rustc_lib,
         )
     elif ctx.attr.tool == "clippy":
         files = depset([toolchain.clippy_driver])
@@ -33,32 +33,32 @@
                 toolchain.clippy_driver,
                 toolchain.rustc,
             ],
-            transitive_files = toolchain.rustc_lib.files,
+            transitive_files = toolchain.rustc_lib,
         )
     elif ctx.attr.tool == "rustc":
         files = depset([toolchain.rustc])
         runfiles = ctx.runfiles(
             files = [toolchain.rustc],
-            transitive_files = toolchain.rustc_lib.files,
+            transitive_files = toolchain.rustc_lib,
         )
     elif ctx.attr.tool == "rustdoc":
         files = depset([toolchain.rust_doc])
         runfiles = ctx.runfiles(
             files = [toolchain.rust_doc],
-            transitive_files = toolchain.rustc_lib.files,
+            transitive_files = toolchain.rustc_lib,
         )
     elif ctx.attr.tool == "rustfmt":
         files = depset([toolchain.rustfmt])
         runfiles = ctx.runfiles(
             files = [toolchain.rustfmt],
-            transitive_files = toolchain.rustc_lib.files,
+            transitive_files = toolchain.rustc_lib,
         )
     elif ctx.attr.tool == "rustc_lib":
-        files = toolchain.rustc_lib.files
+        files = toolchain.rustc_lib
     elif ctx.attr.tool == "rustc_srcs":
         files = toolchain.rustc_srcs.files
     elif ctx.attr.tool == "rust_std" or ctx.attr.tool == "rust_stdlib" or ctx.attr.tool == "rust_lib":
-        files = toolchain.rust_std.files
+        files = toolchain.rust_std
     else:
         fail("Unsupported tool: ", ctx.attr.tool)
 

rust/toolchain.bzl

diff --git a/rust/toolchain.bzl b/rust/toolchain.bzl
index d9eea01..58f58b3 100644
--- a/rust/toolchain.bzl
+++ b/rust/toolchain.bzl
@@ -276,10 +276,10 @@
         clippy_driver = ctx.file.clippy_driver,
         target_json = ctx.file.target_json,
         target_flag_value = ctx.file.target_json.path if ctx.file.target_json else ctx.attr.target_triple,
-        rustc_lib = ctx.attr.rustc_lib,
+        rustc_lib = depset(ctx.files.rustc_lib),
         rustc_srcs = ctx.attr.rustc_srcs,
-        rust_std = rust_std,
-        rust_lib = rust_std,  # `rust_lib` is deprecated and only exists for legacy support.
+        rust_std = rust_std.files,
+        rust_lib = rust_std.files,  # `rust_lib` is deprecated and only exists for legacy support.
         binary_ext = ctx.attr.binary_ext,
         staticlib_ext = ctx.attr.staticlib_ext,
         dylib_ext = ctx.attr.dylib_ext,