absl fails to build with bazel 0.20 due to new_http_archive

[rickeylev]

As of bazel 0.20, it appears that new_http_archive is deprecated in favor of http_archive from the http.bzl starlark extensions. The error message says its a drop in replacement, but this isn't quite true.

Here's the error message with a plain build with bazel 0.20

Starting local Bazel server and connecting to it...
INFO: Invocation ID: 524bae95-f6bf-45f1-9dcc-e51a24c535e9
ERROR: /usr/local/google/home/rlevasseur/absl-gob/PyAbseilCommonLibraries/absl/flags/BUILD:5:1: no such package '@six_archive//': The native new_http_archive rule is deprecated. load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive") for a drop-in replacement.
Use --incompatible_remove_native_http_archive=false to temporarily continue using the native rule. and referenced by '//absl/flags:flags'
ERROR: Analysis of target '//absl:app' failed; build aborted: no such package '@six_archive//': The native new_http_archive rule is deprecated. load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive") for a drop-in replacement.
Use --incompatible_remove_native_http_archive=false to temporarily continue using the native rule.
INFO: Elapsed time: 2.878s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (7 packages loaded, 26 targets configured)
    Fetching @six_archive; fetching

Switching to http.bzl and http_archive gives a different error:

$ bazel build absl:app
INFO: Invocation ID: 97b201ea-ebd5-4d02-8f8f-dae99b4b2458
INFO: Build options have changed, discarding analysis cache.
ERROR: /usr/local/google/home/rlevasseur/absl-gob/PyAbseilCommonLibraries/absl/flags/BUILD:5:1: no such package '@six_archive//': Traceback (most recent call last):
        File "/usr/local/google/home/rlevasseur/.cache/bazel/_bazel_rlevasseur/beec95bc32223bdd257f4689504738ee/external/bazel_tools/tools/build_defs/repo/http.bzl", line 56
                workspace_and_buildfile(ctx)
        File "/usr/local/google/home/rlevasseur/.cache/bazel/_bazel_rlevasseur/beec95bc32223bdd257f4689504738ee/external/bazel_tools/tools/build_defs/repo/utils.bzl", line 60, in workspace_and_buildfile
                ctx.symlink(ctx.attr.build_file, "BUILD.bazel")
Not a regular file: /usr/local/google/home/rlevasseur/absl-gob/PyAbseilCommonLibraries/external/third_party/six.BUILD and referenced by '//absl/flags:flags'
ERROR: Analysis of target '//absl:app' failed; build aborted: no such package '@six_archive//': Traceback (most recent call last):
        File "/usr/local/google/home/rlevasseur/.cache/bazel/_bazel_rlevasseur/beec95bc32223bdd257f4689504738ee/external/bazel_tools/tools/build_defs/repo/http.bzl", line 56
                workspace_and_buildfile(ctx)
        File "/usr/local/google/home/rlevasseur/.cache/bazel/_bazel_rlevasseur/beec95bc32223bdd257f4689504738ee/external/bazel_tools/tools/build_defs/repo/utils.bzl", line 60, in workspace_and_buildfile
                ctx.symlink(ctx.attr.build_file, "BUILD.bazel")
Not a regular file: /usr/local/google/home/rlevasseur/absl-gob/PyAbseilCommonLibraries/external/third_party/six.BUILD
INFO: Elapsed time: 0.371s
INFO: 0 processes.
FAILED: Build did NOT complete successfully (7 packages loaded, 38 targets configured)
    Fetching @six_archive; fetching

Searching around, this looks to be related to maybe this: bazelbuild/bazel#6225
Basically, its not quite a drop-in replacement.

Unfortunately, I wasn't able to get it to work with e.g. build_file="@//:third_party/six.BUILD (as mentioned in the above issue), I think because the "third_party" directory doesn't have a BUILD file (the error it gives refers to being unable to find the bazel package). I can get it to work using build_file_content, though, so I might just use that instead.