Added Posix Shell implementation of Runfiles.

.bazelci/presubmit.yml

@@ -5,7 +5,9 @@ buildifier: 8.2.1
 matrix:
   platform:
     - ubuntu2004
+    - ubuntu2004_arm64
     - macos
+    - macos_arm64
     - windows
   legacy_bazel:
     - 7.*
@@ -62,3 +64,51 @@ tasks:
       - "//tests/..."
     test_targets:
       - "//tests/..."
+  test_module_bzlmod_shell_runfiles:
+    name: "Test module (Bzlmod + Shell Runfiles)"
+    working_directory: "tests/bcr"
+    bazel: ${{ modern_bazel }}
+    platform: ${{ platform }}
+    build_flags:
+      - "--enable_bzlmod"
+      - "--@rules_shell//shell/settings:experimental_use_shell_runfiles=True"
+    build_targets:
+      - "//..."
+    test_flags:
+      - "--enable_bzlmod"
+      - "--@rules_shell//shell/settings:experimental_use_shell_runfiles=True"
+    test_targets:
+      - "//..."
+  test_posix_shell_runfiles:
+    # Explicit dash coverage for the POSIX shell runfiles library. Local
+    # repro: bazel test --config=posix_shell //tests/runfiles/...
+    name: "POSIX Shell Runfiles (dash, ${{modern_bazel}})"
+    bazel: ${{ modern_bazel }}
+    platform: ubuntu2004
+    shell_commands:
+      - "/bin/dash -c 'echo dash ready'"
+    build_flags:
+      - "--config=posix_shell"
+    build_targets:
+      - "//tests/runfiles:runfiles_sh_test"
+    test_flags:
+      - "--config=posix_shell"
+    test_targets:
+      - "//tests/runfiles:runfiles_sh_test"
+  test_module_workspace_shell_runfiles:
+    name: "Test module (${{legacy_bazel}}, WORKSPACE + Shell Runfiles)"
+    working_directory: "tests/bcr"
+    bazel: ${{ legacy_bazel }}
+    platform: ${{ platform }}
+    build_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
+      - "--@rules_shell//shell/settings:experimental_use_shell_runfiles=True"
+    build_targets:
+      - "//..."
+    test_flags:
+      - "--noenable_bzlmod"
+      - "--enable_workspace"
+      - "--@rules_shell//shell/settings:experimental_use_shell_runfiles=True"
+    test_targets:
+      - "//..."

.bazelrc

@@ -1,2 +1,8 @@
 common --check_direct_dependencies=off
 common --keep_going
+
+# --config=posix_shell forces the sh_toolchain to resolve to /bin/dash via
+# BAZEL_SH. Used by the `test_posix_shell_runfiles` presubmit task and
+# available locally: `bazel test --config=posix_shell //tests/runfiles/...`.
+# Only takes effect on hosts where /bin/dash exists (i.e. Debian/Ubuntu).
+common:posix_shell --repo_env=BAZEL_SH=/bin/dash

.bcr/presubmit.yml

@@ -6,8 +6,9 @@ bcr_test_module:
       - debian10
       - ubuntu2004
       - macos
+      - macos_arm64
       - windows
-    bazel: [6.x, 7.x, 8.x]
+    bazel: [7.x, 8.x, 9.x]
   tasks:
     run_test_module:
       name: Run test module

MODULE.bazel

@@ -12,7 +12,7 @@ use_repo(sh_configure, "local_config_shell")
 
 register_toolchains("@local_config_shell//:all")
 
-bazel_dep(name = "rules_shellcheck", version = "0.6.2", dev_dependency = True)
+bazel_dep(name = "rules_shellcheck", version = "0.6.4", dev_dependency = True)
 bazel_dep(name = "rules_testing", version = "0.9.0", dev_dependency = True)
 bazel_dep(name = "stardoc", version = "0.8.1", dev_dependency = True)
 bazel_dep(name = "with_cfg.bzl", version = "0.14.1", dev_dependency = True)

shell/private/BUILD

@@ -10,4 +10,5 @@ bzl_library(
         "sh_test.bzl",
     ],
     visibility = ["//shell:__pkg__"],
+    deps = ["@bazel_skylib//rules:common_settings"],
 )

shell/private/sh_executable.bzl

@@ -14,12 +14,16 @@
 
 """Common code for sh_binary and sh_test rules."""
 
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load(":providers.bzl", "ShBinaryInfo", "ShInfo")
 
 visibility(["//shell"])
 
 _SH_TOOLCHAIN_TYPE = Label("//shell:toolchain_type")
 
+_BASH_RUNFILES_INIT_PATH = "bazel_tools/tools/bash/runfiles/runfiles.bash"
+_SHELL_RUNFILES_INIT_PATH = "shell/runfiles/runfiles.sh"
+
 def _to_rlocation_path(ctx, file):
     if file.short_path.startswith("../"):
         return file.short_path[3:]
@@ -49,12 +53,16 @@ def _sh_executable_impl(ctx):
         else:
             shell = ctx.toolchains[_SH_TOOLCHAIN_TYPE].path
             shebang = "#!{}".format(shell)
+        if ctx.attr._use_shell_runfiles[BuildSettingInfo].value:
+            init_path = _SHELL_RUNFILES_INIT_PATH
+        else:
+            init_path = _BASH_RUNFILES_INIT_PATH
         ctx.actions.write(
             entrypoint,
             content = """{shebang}
 
 # --- begin runfiles.bash initialization v3 ---
-set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+set -uo pipefail; set +e; f={init_path}
 # shellcheck disable=SC1090
 source "${{RUNFILES_DIR:-/dev/null}}/$f" 2>/dev/null || \
   source "$(grep -sm1 "^$f " "${{RUNFILES_MANIFEST_FILE:-/dev/null}}" | cut -f2- -d' ')" 2>/dev/null || \
@@ -69,6 +77,7 @@ runfiles_export_envvars
 exec "$(rlocation "{src}")" "$@"
 """.format(
                 shebang = shebang,
+                init_path = init_path,
                 src = _to_rlocation_path(ctx, src),
             ),
             is_executable = True,
@@ -259,6 +268,10 @@ The file containing the shell script.
             "_runfiles_dep": attr.label(
                 default = Label("//shell/runfiles"),
             ),
+            "_use_shell_runfiles": attr.label(
+                default = Label("//shell/settings:experimental_use_shell_runfiles"),
+                providers = [BuildSettingInfo],
+            ),
             "_windows_constraint": attr.label(
                 default = "@platforms//os:windows",
             ),

shell/runfiles/BUILD

@@ -1,16 +1,33 @@
 load("//shell:sh_library.bzl", "sh_library")
 load("//shell/private:root_symlinks.bzl", "ROOT_SYMLINKS_SUPPORTED", "root_symlinks")
 
+config_setting(
+    name = "use_shell_runfiles",
+    flag_values = {"//shell/settings:experimental_use_shell_runfiles": "true"},
+)
+
 alias(
     name = "runfiles",
-    actual = ":runfiles_impl" if ROOT_SYMLINKS_SUPPORTED else "@bazel_tools//tools/bash/runfiles",
+    actual = select({
+        ":use_shell_runfiles": ":runfiles_sh_impl",
+        "//conditions:default": ":runfiles_impl" if ROOT_SYMLINKS_SUPPORTED else "@bazel_tools//tools/bash/runfiles",
+    }),
     visibility = ["//visibility:public"],
 )
 
 sh_library(
     name = "runfiles_impl",
     data = [":runfiles_at_legacy_location"],
     tags = ["manual"],
+    visibility = ["//visibility:public"],
+    deps = [":runfiles_bash"],
+)
+
+sh_library(
+    name = "runfiles_bash",
+    srcs = ["runfiles.bash"],
+    tags = ["manual"],
+    visibility = ["//visibility:public"],
 )
 
 root_symlinks(
@@ -21,7 +38,58 @@ root_symlinks(
     tags = ["manual"],
 )
 
+sh_library(
+    name = "runfiles_sh_impl",
+    data = [
+        ":runfiles_sh_at_documented_location",
+        ":runfiles_sh_at_legacy_location",
+    ],
+    tags = ["manual"],
+    visibility = ["//visibility:public"],
+    deps = [":runfiles_sh"],
+)
+
+sh_library(
+    name = "runfiles_sh",
+    srcs = ["runfiles.sh"],
+    tags = ["manual"],
+    visibility = ["//visibility:public"],
+)
+
+# Place runfiles.sh at the root path used by the documented init snippet
+# (`f=shell/runfiles/runfiles.sh`). Without this, the file would only appear
+# under its repo-prefixed location (e.g. `_main/shell/runfiles/runfiles.sh`
+# or `rules_shell+/shell/runfiles/runfiles.sh`) and copy-pasting the snippet
+# would fail with `ERROR: cannot find shell/runfiles/runfiles.sh`.
+root_symlinks(
+    name = "runfiles_sh_at_documented_location",
+    root_symlinks = {
+        "runfiles.sh": "shell/runfiles/runfiles.sh",
+    },
+    tags = ["manual"],
+)
+
+# Native `sh_test` (used when Bazel exposes it — legacy 7/8 modes and some
+# launcher paths) hardcodes `f=bazel_tools/tools/bash/runfiles/runfiles.bash`
+# in its generated launcher and cannot be redirected from Starlark. When the
+# `experimental_use_shell_runfiles` flag swaps the `:runfiles` alias to this
+# target, that path must still resolve to something sourceable — otherwise
+# every native sh_test in the build dies with
+# `ERROR: cannot find bazel_tools/tools/bash/runfiles/runfiles.bash`.
+# Bash and sh impls never appear in the same runfiles tree (the alias uses a
+# mutually-exclusive select), so the shared path is safe.
+root_symlinks(
+    name = "runfiles_sh_at_legacy_location",
+    root_symlinks = {
+        "runfiles.sh": "bazel_tools/tools/bash/runfiles/runfiles.bash",
+    },
+    tags = ["manual"],
+)
+
 exports_files(
-    ["runfiles.bash"],
+    [
+        "runfiles.bash",
+        "runfiles.sh",
+    ],
     visibility = ["//tests/runfiles:__pkg__"],
 )