Inconsistent behaviors of --repo_env option #8869
Description
Description of the problem / feature request:
Using --repo_env to invalidate a repository rule has inconsistent behavior between a first-time run with vs. without --repo_env added.
Also there is strange behavior between bazel shutdown and re-running bazel build with the repo_env option where a download re-occurs everytime when repo_env was first used, but does not re-occur when it was not used (caching problem).
And finally changing values of repo_env for env vars that a repository rule does not declare it cares about with repository_ctx.environ will cause it to be reran anyway.
Feature requests: what underlying problem are you trying to solve with this feature?
I am trying to use --repo_env to make repository rules that declare a dependency via environ on an env var to be rerun only when the env var changes.
Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.
- Create an empty
BUILD.bazelfile - Create a
WORKSPACEfile
load("//:my_repository_rule.bzl", "my_repository_rule")
my_repository_rule(
name = "my_repository_rule",
)
- Create a
my_repository_rule.bzlfile
def _my_repository_rule_impl(rctx):
foo = rctx.os.environ.get("foo", default = "")
print('foo = ' + foo)
rctx.file("BUILD.bazel", """
genrule(
name = "test",
srcs = [],
outs = ["test.txt"],
cmd = "echo test > $@",
)
""")
rctx.download_and_extract(
url = "https://github.com/torvalds/linux/archive/v5.2.zip"
)
my_repository_rule = repository_rule(
environ = ["foo"],
implementation = _my_repository_rule_impl,
)
Enter a docker shell with the latest bazel release.
docker run -it -v $(pwd):/bazel -v $(pwd)/../bazel-cache:/root/.cache/bazel --workdir /bazel --entrypoint /bin/bash l.gcr.io/google/bazel:0.28.0
Run various bazel build commands and view inconsistent behaviors.
Make sure to exit the docker shell and do sudo rm -rf ../bazel-cache between below examples.
# First time run without --repo_env, downloads as expected
bazel build @my_repository_rule//...
# Now add --repo_env, does not redownload which is a problem
bazel build --repo_env=foo=bar @my_repository_rule//...
# First time run with --repo_env=foo=bar, downloads as expected
bazel build --repo_env=foo=bar @my_repository_rule//...
# Change --repo_env value, redownloads as expected
bazel build --repo_env=foo=baz @my_repository_rule//...
# Remove --repo_env, redownloads as expected
bazel build @my_repository_rule//...
# Now add --repo_env, does not redownload which is a problem
bazel build --repo_env=foo=bar @my_repository_rule//...
# First time run without --repo_env, downloads as expected
bazel build @my_repository_rule//...
bazel shutdown
# Re-run, does not redownload as expected
bazel build @my_repository_rule//...
# First time run with --repo_env=foo=bar, downloads as expected
bazel build --repo_env=foo=bar @my_repository_rule//...
bazel shutdown
# Re-run with same value of repo_env, it redownloads again which is a problem
bazel build --repo_env=foo=bar @my_repository_rule//...
# First time run with --repo_env=one=two, downloads as expected
# NOTE: my understanding is the repository rule should only care about values of foo because of environ = ["foo"]
bazel build --repo_env=one=two @my_repository_rule//...
# Change value to --repo_env=one=three, I expect it should not re-run because the rule does not declare that it cares about values of "one", however it redownloads which is a problem
bazel build --repo_env=one=three @my_repository_rule//...
What operating system are you running Bazel on?
Ubuntu 16.04
What's the output of bazel info release?
release 0.28.0