Use print instead of po in debuginfo path test by fallofpheonix · Pull Request #156769 · rust-lang/rust

fallofpheonix · 2026-05-20T08:55:53Z

This fixes tests/debuginfo/path.rs failing on newer Apple LLDB versions.

Root cause:
Apple LLDB 2100 reports missing Rust language plugin support:

warning: po was unsuccessful, running p instead

As a result, po falls back to p, producing expanded output that no longer matches the existing lldb-check directives.

Changes:

replace po with print
relax lldb-check expectations using [...]
preserve validation of the displayed path value

This also aligns path.rs with the rest of the debuginfo tests, as it appears to be the only test using po.

EDIT(@jieyouxu): see digging #156769 (comment)

rustbot · 2026-05-20T08:55:59Z

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fallofpheonix · 2026-05-20T08:56:01Z

Reproduced on Apple LLDB 2100.

po falls back to p because LLDB reports missing Rust language plugin support. path.rs appears to be the only debuginfo test using po.

Submitted a PR replacing po with print and relaxing the checks.

rustbot · 2026-05-20T19:09:33Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

fallofpheonix · 2026-05-20T20:33:58Z

Thanks, that makes sense.

I investigated this further on my side as well. I checked an older revision (281c97c) and tests/debuginfo/path.rs still fails for me on Apple LLDB 2100, so it did not look like a recent regression in Rust itself.

path.rs was added for Path / PathBuf pretty printer support, and it appears to be the only debuginfo test currently using po.

The pretty printers still seem to work correctly through print; the failure comes from po falling back to p on Apple LLDB 2100.

If this is indeed related to #147552, I'm happy to adjust the approach or update the PR accordingly.

workingjubilee · 2026-05-21T02:31:28Z

The actual root cause is simply that we do not test this version in CI. I believe we test LLDB 1703 now? See

@bors try jobs=aarch64-apple

Making the test more tolerant by making it accept virtually anything with the same prefix, when it previously tested for two different output formats, one significantly more verbose than the test checks for, does seem to defeat the purpose of having a test here.

Use print instead of po in debuginfo path test try-job: aarch64-apple

rust-bors · 2026-05-21T05:57:48Z

☀️ Try build successful (CI)
Build commit: 7ca6154 (7ca61549aa9da0d8349ccec9e4569b85d307fb77, parent: b954122bbe6c4a244c511a9a168c6d5438d8f58f)

jieyouxu

Sorry, I did some more digging, and I now think that we should indeed remove the po cmd/checks based on dug up info. Can you undo the check relaxation for print?

@rustbot author

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jieyouxu · 2026-05-23T18:59:26Z

Suggestion: okay, so I did some more digging with the help of @NobodyNada (thanks!!), and this is what I can gather (likely contains inaccuracies, happy to be corrected):

po is (typically) aliased to expr --object-description, which lldb 21 says
-O ( --object-description ) Display using a language-specific description API, if possible.

The problem is that AFAIK expr (and thus po) tries to "[e]valuate an expression on the current thread" plus --object-description will try to find a language-specific description API where possible

Rust doesn't really have this "language-specific description API" (objective C / swift have that upstream AFAICT)

Fallback logic previously was sth like (1) try to find lang-specific description API, (2) fallback to p (basic expr) if not found (in our case printing the "data" "/some/path"), silently.

@NobodyNada helped to bisect the difference to [lldb] Print ValueObject when GetObjectDescription fails llvm/llvm-project#152417 which AFAICT (IMO very correctly) changes the silent fallback to actually show a warning.

The existing //@ lldb-check:"/some/path" fails, because the warnings of course are extra bits, and it's not just a naive "print the data" but instead falls back to p path or expr path.

Also, note that on more recent versions of lldb, print is usually aliases to dwim-print (Do What I Mean™️ print).

IOW, I think the original po checks happened to accidentally work as it relied on a specific silent fallback behavior, and I think we should just avoid trying to test that. Sure, users can and will try to po path w/ an error message, but at least they still get p path back.

Example failure (lldb 22):

po path error: not a pointer type (&std::path::Path) "/some/path" { data_ptr = 0x0000000100000b58 length = 10 } # what `p path` fallback looks like p path (&std::path::Path) "/some/path" { data_ptr = 0x0000000100000b58 length = 10 }

For our purposes, I do agree (now) that print (DWIM print) is good enough tbh, and it's probably the best we can do absent actual upstream object description API support (happy to be corrected on this front).

I however suggest only removing the po lines and their corresponding check, but don't relax the check on print {path,pathbuf}, i.e. only do

diff --git a/tests/debuginfo/path.rs b/tests/debuginfo/path.rs index 27b518fd897..2fffadd8510 100644 --- a/tests/debuginfo/path.rs +++ b/tests/debuginfo/path.rs @@ -8,12 +8,8 @@ //@ lldb-command:print pathbuf //@ lldb-check:[...] "/some/path" { inner = "/some/path" { inner = { inner = size=10 { [0] = '/' [1] = 's' [2] = 'o' [3] = 'm' [4] = 'e' [5] = '/' [6] = 'p' [7] = 'a' [8] = 't' [9] = 'h' } } } } -//@ lldb-command:po pathbuf -//@ lldb-check:"/some/path" //@ lldb-command:print path //@ lldb-check:[...] "/some/path" { data_ptr = [...] length = 10 } -//@ lldb-command:po path -//@ lldb-check:"/some/path"

fallofpheonix · 2026-05-23T19:13:50Z

Updated.

I restored the original print checks and only removed the po command/check pairs as suggested. The test now continues to validate the existing pretty printer output while avoiding the po fallback behavior.

fallofpheonix · 2026-05-23T19:14:14Z

@rustbot ready

jieyouxu · 2026-05-23T19:16:41Z

@bors try jobs=aarch64-apple

Use print instead of po in debuginfo path test try-job: aarch64-apple

rust-bors · 2026-05-23T21:46:24Z

☀️ Try build successful (CI)
Build commit: a7dc997 (a7dc9977bcb9500ad27d60cf50a4eec6a19e3ac4, parent: 54333ff079780f803f65dcee30c544050b35f544)

jieyouxu

@bors r+

View changes since this review

rust-bors · 2026-05-24T06:01:47Z

📌 Commit 6ed5bf2 has been approved by jieyouxu

It is now in the queue for this repository.

rust-bors · 2026-05-24T06:27:48Z

⌛ Testing commit 6ed5bf2 with merge 30e8a87...

Workflow: https://github.com/rust-lang/rust/actions/runs/26354003258

@jieyouxu

Use print instead of po in debuginfo path test Fixes #156660 This fixes `tests/debuginfo/path.rs` failing on newer Apple LLDB versions. Root cause: Apple LLDB 2100 reports missing Rust language plugin support: warning: `po` was unsuccessful, running `p` instead As a result, `po` falls back to `p`, producing expanded output that no longer matches the existing `lldb-check` directives. Changes: - replace `po` with `print` - relax `lldb-check` expectations using `[...]` - preserve validation of the displayed path value This also aligns `path.rs` with the rest of the debuginfo tests, as it appears to be the only test using `po`. --- EDIT(@jieyouxu): see digging #156769 (comment)

JonathanBrouwer · 2026-05-24T06:29:22Z

@bors yield
Yielding to enclosing rollup

rust-bors · 2026-05-24T06:29:26Z

Auto build was cancelled. Cancelled workflows:

https://github.com/rust-lang/rust/actions/runs/26354003258

The next pull request likely to be tested is #156870.

…uwer Rollup of 6 pull requests Successful merges: - #156769 (Use print instead of po in debuginfo path test) - #156784 (Fix reborrow_info early return skipping field validation) - #156827 (float_literal_f32_fallback: Don't suggest invalid code) - #156828 (Add unstable Share trait) - #156830 (Add `#[doc(alias = "phi")]` for float `GOLDEN_RATIO` constants) - #156860 (Fix Pieter-Louis Schoeman mailmap entry)

Use print instead of po in debuginfo path test

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Auto merge of #156769 - fallofpheonix:fix-path-lldb-macos, r=<try>

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Use print instead of po in debuginfo path test try-job: aarch64-apple

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tests/debuginfo/path.rs test failing on MacOS #156660

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Remove po checks from debuginfo path test

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Auto merge of #156769 - fallofpheonix:fix-path-lldb-macos, r=<try>

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Use print instead of po in debuginfo path test try-job: aarch64-apple

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Rollup of 6 pull requests #156870

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