`./x.py dist` fails in `rust 1.71.0` on `lint-docs`

[jpalus]

Build of rust 1.71.0 fails on Linux/aarch64 (bootstrapped by system rust 1.70.0) with:

running: LD_LIBRARY_PATH="/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/lib:/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/lib" RUSTC="/usr/bin/rustc" RUSTC_BOOTSTRAP="1" "/home
/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage0-tools-bin/lint-docs" "--src" "/home/users/builder/rpm/BUILD/rustc-1.71.0-src/compiler" "--out" "/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/
md-doc/rustc/src/lints" "--rustc" "/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "--rustc-target" "aarch64-unknown-linux-gnu" "--verbose"                                                                    
compiling lint forbidden_lint_groups                                                                                                                                                                                                                            
running: cd "/home/users/builder/tmp/.tmpxILHkF" && "/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "--edition=2018" "--error-format=json" "--target" "aarch64-unknown-linux-gnu" "lint_example.rs"           
warning: the code example in lint `forbidden_lint_groups` in /home/users/builder/rpm/BUILD/rustc-1.71.0-src/compiler/rustc_lint_defs/src/builtin.rs failed to generate the expected output: did not find lint `forbidden_lint_groups` in output of example, got:
/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/bin/rustc: error while loading shared libraries: librustc_driver-c3edb2d0282ade3e.so: cannot open shared object file: No such file or directory                           
                                                                                                                                                                                                                                                                
compiling lint ill_formed_attribute_input                                                                                                                                                                                                                       
running: cd "/home/users/builder/tmp/.tmpoGbUcU" && "/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "--edition=2018" "--error-format=json" "--target" "aarch64-unknown-linux-gnu" "lint_example.rs"           
warning: the code example in lint `ill_formed_attribute_input` in /home/users/builder/rpm/BUILD/rustc-1.71.0-src/compiler/rustc_lint_defs/src/builtin.rs failed to generate the expected output: did not find lint `ill_formed_attribute_input` in output of exa
mple, got:                                                                                                                                                                                                                                                      
/home/users/builder/rpm/BUILD/rustc-1.71.0-src/build/aarch64-unknown-linux-gnu/stage2/bin/rustc: error while loading shared libraries: librustc_driver-c3edb2d0282ade3e.so: cannot open shared object file: No such file or directory

I believe the culprit is explicit removal of LD_LIBRARY_PATH despite it being apparently necessary in this case:

rust/src/tools/lint-docs/src/lib.rs

Line 411 in 8ede3aa

cmd.env_remove("LD_LIBRARY_PATH");

I see on master this was already reverted in 67b5990 but looks like it missed the release.

[Noratrieb]

@jyn514

[jyn514]

this is a question for t-release, not bootstrap. 67b5990 depends on the whole PR, and that PR changes quite a lot, but the changes are only to download-rustc and not to the rest of the build system.

[cuviper]

67b5990 depends on the whole PR

Why is that? It's a clean git cherry-pick, at least, and I don't see why it would logically depend on the rest of that PR.

[jyn514]

@cuviper it depends on baae59e, or else lint-docs tests will fail when download-rustc and assertions are both enabled.

(and i am considering reverting baae59e soon: #112143 (comment))

[cuviper]

or else lint-docs tests will fail when download-rustc and assertions are both enabled.

Well, that seems to me an unlikely combination for stable builds.

[cuviper]

We discussed this last week and agreed to pull 67b5990 into 1.71.1:
https://rust-lang.zulipchat.com/#narrow/stream/241545-t-release/topic/meeting.202023.2007.2021/near/377344265

(and to avoid regression, it should go into 1.72-beta as well)

@rustbot label +stable-accepted +beta-accepted