Unable to load file '@bazel_version//:def.bzl': file doesn't exist

[jonhoo]

With this WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "io_bazel_rules_rust",
    sha256 = "9f38c5fbf37b0dc445fe54558e14ac000cca0be6907251c6df21ba236acd59a8",
    strip_prefix = "rules_rust-ec436b5ff2ab1ddeba6f27a7a1a5d263812981a6",
    urls = [
        # Master branch as of 2019-11-11
        "https://github.com/bazelbuild/rules_rust/archive/ec436b5ff2ab1ddeba6f27a7a1a5d263812981a6.zip",
    ],
)

http_archive(
    name = "bazel_skylib",
    sha256 = "9a737999532daca978a158f94e77e9af6a6a169709c0cee274f0a4c3359519bd",
    strip_prefix = "bazel-skylib-1.0.0",
    url = "https://github.com/bazelbuild/bazel-skylib/archive/1.0.0.tar.gz",
)

load("@io_bazel_rules_rust//rust:repositories.bzl", "rust_repositories")
rust_repositories()

load("@io_bazel_rules_rust//:workspace.bzl", "bazel_version")
bazel_version(name = "bazel_version")

And bazel version 1.1.0, bazel fetch fails with

ERROR: error loading package 'rust': in /home/jon/.cache/bazel/_bazel_jon/66db7c3492b5fc3fa5db2c66360c215b/external/io_bazel_rules_rust/bindgen/bindgen.bzl: in /home/jon/.cache/bazel/_bazel_jon/66db7c3492b5fc3fa5db2c66360c215b/external/io_bazel_rules_rust/rust/rust.bzl: in /home/jon/.cache/bazel/_bazel_jon/66db7c3492b5fc3fa5db2c66360c215b/external/io_bazel_rules_rust/rust/private/rustdoc_test.bzl: in /home/jon/.cache/bazel/_bazel_jon/66db7c3492b5fc3fa5db2c66360c215b/external/io_bazel_rules_rust/rust/private/rustc.bzl: Unable to load file '@bazel_version//:def.bzl': file doesn't exist

The crux of this appears to be

Unable to load file '@bazel_version//:def.bzl': file doesn't exist

[jonhoo]

Which I believe stems from:

rules_rust/rust/private/rustc.bzl

Line 26 in fe9a91e

load("@bazel_version//:def.bzl", "BAZEL_VERSION")

[m3rcuriel]

Can you paste more of your failed output here? I'm struggling to reproduce this.

[jonhoo]

Huh, strange, I cannot reproduce it anymore myself either. May have been a transient issue. I'll post more details if I run into it again!

[wchargin]

I’m running into this due to a naming conflict. μpb, a dependency of the
official protobuf/grpc repo, also defines a bazel_version repository
for the same purpose, but theirs has a different structure.

upb’s:

https://github.com/protocolbuffers/upb/blob/c1357afb2e39df671d89eaec49033b5329f36a3e/bazel/repository_defs.bzl#L9-L10

rules_rust’s:

rules_rust/workspace.bzl

Lines 24 to 25 in 9279938

	repository_ctx.file("BUILD.bazel", "exports_files(['def.bzl'])")
	repository_ctx.file("def.bzl", "BAZEL_VERSION='" + bazel_version + "'")

Thus, we get “file doesn’t exist” because their repository rule runs
first and rules_rust’s is ignored. Checking the directory structure
confirms that there is a bazel_version.bzl and not a def.bzl.

I have a repro that’s as minimal as I can make it (removing any line
breaks the repro), but not as minimal as I’d like. (The proto build
system is… difficult.) Here it is:

WORKSPACE

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "io_bazel_rules_closure",
    sha256 = "6a900831c1eb8dbfc9d6879b5820fd614d4ea1db180eb5ff8aedcb75ee747c1f",
    strip_prefix = "rules_closure-db4683a2a1836ac8e265804ca5fa31852395185b",
    urls = [
        "http://mirror.tensorflow.org/github.com/bazelbuild/rules_closure/archive/db4683a2a1836ac8e265804ca5fa31852395185b.tar.gz",
        "https://github.com/bazelbuild/rules_closure/archive/db4683a2a1836ac8e265804ca5fa31852395185b.tar.gz",  # 2020-01-15
    ],
)

load("@io_bazel_rules_closure//closure:repositories.bzl", "rules_closure_dependencies")
rules_closure_dependencies(
    omit_bazel_skylib = True,
    omit_com_google_protobuf = True,
    omit_com_google_protobuf_js = True,
)

http_archive(
    name = "org_tensorflow",
    # NOTE: when updating this, MAKE SURE to also update the protobuf_js runtime version
    # in third_party/workspace.bzl to >= the protobuf/protoc version provided by TF.
    sha256 = "2595a5c401521f20a2734c4e5d54120996f8391f00bb62a57267d930bce95350",
    strip_prefix = "tensorflow-2.3.0",
    urls = [
        "http://mirror.tensorflow.org/github.com/tensorflow/tensorflow/archive/v2.3.0.tar.gz",  # 2020-07-23
        "https://github.com/tensorflow/tensorflow/archive/v2.3.0.tar.gz",
    ],
)

load("@org_tensorflow//tensorflow:workspace.bzl", "tf_workspace")
tf_workspace()

load("@com_github_grpc_grpc//bazel:grpc_deps.bzl", "grpc_deps")

grpc_deps()

load("@upb//bazel:repository_defs.bzl", "bazel_version_repository")

# This next line breaks the build, but without it we can't build protos.
bazel_version_repository(name = "bazel_version")

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "io_bazel_rules_rust",
    sha256 = "618cba29165b7a893960de7bc48510b0fb182b21a4286e1d3dbacfef89ace906",
    strip_prefix = "rules_rust-5998baf9016eca24fafbad60e15f4125dd1c5f46",
    urls = [
        # Master branch as of 2020-09-24
        "https://github.com/bazelbuild/rules_rust/archive/5998baf9016eca24fafbad60e15f4125dd1c5f46.tar.gz",
    ],
)

load("@io_bazel_rules_rust//rust:repositories.bzl", "rust_repositories")

rust_repositories()

load("@io_bazel_rules_rust//:workspace.bzl", "rust_workspace")

rust_workspace()

BUILD

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_binary", "rust_library", "rust_test")

package(default_visibility = ["//visibility:private"])

licenses(["notice"])

rust_library(
    name = "mylib",
    srcs = [
        "lib.rs",
    ],
)

.bazelrc

common --experimental_repo_remote_exec

lib.rs

Empty file.

Command line session

$ grep -B1 name BUILD
rust_library(
    name = "mylib",
$ bazel build :mylib
ERROR: Skipping ':mylib': error loading package '': in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/rust.bzl: in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/private/rustdoc_test.bzl: in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/private/rustc.bzl: Unable to load file '@bazel_version//:def.bzl': file doesn't exist
WARNING: Target pattern parsing failed.
ERROR: error loading package '': in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/rust.bzl: in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/private/rustdoc_test.bzl: in /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/io_bazel_rules_rust/rust/private/rustc.bzl: Unable to load file '@bazel_version//:def.bzl': file doesn't exist
INFO: Elapsed time: 0.080s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (1 packages loaded)
$ ls /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/bazel_version
bazel_version.bzl  BUILD  WORKSPACE
$ cat /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/bazel_version/bazel_version.bzlbazel_version = "2.1.0"$ 
$ cat /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/bazel_version/bazel_version.bzl; echo
bazel_version = "2.1.0"
$ sed -i -e '/bazel_version_repository/ s/^/#/' WORKSPACE
$ bazel build :mylib
INFO: Analyzed target //:mylib (26 packages loaded, 186 targets configured).
INFO: Found 1 target...
Target //:mylib up-to-date:
  bazel-bin/libmylib--1103081910.rlib
INFO: Elapsed time: 1.100s, Critical Path: 0.67s
INFO: 5 processes: 5 linux-sandbox.
INFO: Build completed successfully, 9 total actions
$ ls /HOMEDIR/.cache/bazel/_bazel_wchargin/bf4ce76fb2a3b9593d6023d4a99e07e4/external/bazel_version
BUILD  def.bzl  WORKSPACE

Bazel version: bazel info release = release 2.1.0

---

It looks like upb may have gotten rid of theirs at head, so I’ll see
if we can upgrade on our end, but we’d have to get TensorFlow to
upgrade, too, so it may or may not be trivial. I wonder whether an easy
workaround on our end could be to rename our bazel_version_repository
to something that doesn’t conflict? Like:

diff --git a/docs/BUILD b/docs/BUILD
index 19bb042..cc7002f 100644
--- a/docs/BUILD
+++ b/docs/BUILD
@@ -7,7 +7,7 @@ bzl_library(
     name = "all_deps",
     srcs = [
         "@bazel_tools//tools:bzl_srcs",
-        "@bazel_version//:def.bzl",
+        "@io_bazel_rules_rust_bazel_version//:def.bzl",
     ],
     deps = [
         "@bazel_skylib//lib:versions",
diff --git a/rust/private/rustc.bzl b/rust/private/rustc.bzl
index c3d5f9b..ea84b2e 100644
--- a/rust/private/rustc.bzl
+++ b/rust/private/rustc.bzl
@@ -23,7 +23,7 @@ load(
     "find_cpp_toolchain",
 )
 load("@bazel_skylib//lib:versions.bzl", "versions")
-load("@bazel_version//:def.bzl", "BAZEL_VERSION")
+load("@io_bazel_rules_rust_bazel_version//:def.bzl", "BAZEL_VERSION")
 
 CrateInfo = provider(
     fields = {
diff --git a/workspace.bzl b/workspace.bzl
index d54ac1e..fe14180 100644
--- a/workspace.bzl
+++ b/workspace.bzl
@@ -29,5 +29,5 @@ def rust_workspace():
 
     bazel_skylib_workspace()
 
-    bazel_version(name = "bazel_version")
+    bazel_version(name = "io_bazel_rules_rust_bazel_version")
 

This patch seems to solve the problem for me, so I’ll submit a PR.