while compiling cc_library from DefaultInfo bazel ignores bazelrc

[onelxj]

Description of the bug:

I have a rule that returns DefaultInfo(depset(...)) - folder that consists of c++ sources and headers, then I'm trying to compile it with

cc_library(
    name = "route-guide-eventuals-library",
    srcs = [
        ":route-guide-eventuals-generated",  # Default info with srcs
    ],
    hdrs = [
        ":route-guide-eventuals-generated",  # Default info with srcs
    ],
    # Can't get .bazelrc settings for generated files.
    # copts = ["-std=c++17"],
    alwayslink = True,
    deps =[
        ":route-guide-grpc",
    ]
)

The sources require c++17, in bazelrc I have

build:linux --cxxopt='-std=c++17'
build:linux --host_cxxopt=-std=c++17

but whenever I try to run - it uses C++11 instead of 17
if uncomment copts, that includes '-std=c++17' - it works

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

No response

Which operating system are you running Bazel on?

Linux Ubuntu 22.04

What is the output of bazel info release?

release 5.1.1

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

No response

[onelxj]

Fixed via adding build --action_env=BAZEL_CXXOPTS="-std=c++17" to bazelrc

Thanks =)

[fmeum]

Fixed via adding build --action_env=BAZEL_CXXOPTS="-std=c++17" to bazelrc

Thanks =)

--repo_env should work better as it doesn't pollute the environment of every action.
Also, please keep in mind that what counts for the deps of a cc_library is what's in the CcInfo of your custom rule, not in DefaultInfo. If all you do is generate files, you may want to reference the custom rule from srcs, not deps.

[onelxj]

Fixed via adding build --action_env=BAZEL_CXXOPTS="-std=c++17" to bazelrc
Thanks =)

--repo_env should work better as it doesn't pollute the environment of every action. Also, please keep in mind that what counts for the deps of a cc_library is what's in the CcInfo of your custom rule, not in DefaultInfo. If all you do is generate files, you may want to reference the custom rule from srcs, not deps.

That my fault, generated stuff is :route-guide-eventuals-generated, it is in srcs and hdrs already, thanks!

[onelxj]

@fmeum Could you please explain, why defaul bazel:linux --cxxopt='-std=c++17' is not valid for this build? Other srcs in the repo that copliling also with cc_library work fine

[fmeum]

@onelxj Do you have a complete example reproducing the issue you could share? In a local example I tried --cxxopt did apply to generated files with e.g. .cpp extensions.

[onelxj]

@fmeum the thing there that target provided in :route-guide-eventuals-generated is a folder (generated via declare_folder()), I'm not sure, but it can be the reason

[fmeum]

That makes a big difference and is likely the reason. However, I'm not familiar enough with the C++ rules to say whether it can be fixed.

@onelxj Could you reopen the issue so that it can be proberly triaged to the C++ team?

[onelxj]

That makes a big difference and is likely the reason. However, I'm not familiar enough with the C++ rules to say whether it can be fixed.

@onelxj Could you reopen the issue so that it can be probably triaged to the C++ team?

Thank you for your time!

[Mizux]

Trying to force C++ dialect (std c++17) in subcommands on various platforms and using various bazel build arguments…

Project \  Platform	gLinux Linux github	gMacOS (Intel/M1)	MacOS github (intel)	gWindows Windows github
Repo:bazel-cpp Branch: arg –cxxopt=”-std=c++17”	APPEND	APPEND	APPEND	ADDED
Repo:bazel-cpp Branch: env –action_env=BAZEL_CXXOPTS=”-std=c++17”	REPLACE	REPLACE	IGNORED	IGNORED
Repo:bazel-proto protobuf v21.12 –cxxopt=”-std=c++17”	APPEND	APPEND	APPEND	ADDED
Repo:bazel-proto protobuf v21.12 –action_env=BAZEL_CXXOPTS=”-std=c++17”	REPLACE	REPLACE	IGNORED C++11 used -> absl build fail	IGNORED
Repo:bazel-proto Branch: arg protobuf v22.2 + Fix #12320 –cxxopt=”-std=c++17”	IGNORED C++0x used absl build fail	IGNORED C++0x used -> absl build fail	APPEND	IGNORED
Repo: bazel-proto Branch: env protobuf v22.2 + Fix #12320 –action_env=BAZEL_CXXOPTS=”-std=c++17”	REPLACE	REPLACE bug #12306	IGNORED C++11 used -> absl build fail	IGNORED

Legend:

• ADDED: the c++17 flag is added to the subcommand
• APPEND: std=c++17 is appended in the subcommand (i.e. the default flag is still present)
• REPLACE: the default flag is replaced by the one passed as argument
• IGNORED: the flags argument seems completely ignored/dropped and I can’t find it in any subcommand trace log

dev note: use --subcommands=true or -s to get # SUBCOMMAND ... trace log
repo: https://mizux.dev/bazel-cpp
repo: https://mizux.dev/bazel-proto

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[github-actions]

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