fix: correctly handle pipe errors in builtins

[reubeno]

This should, among other things, resolve some of the flaky tests we've seen very recently. Those were cases where a pipe error was sometimes getting returned by the printf builtin.

[github-actions]

Test Results

    3 files     32 suites   11m 4s ⏱️
1 605 tests 1 605 ✅ 0 💤 0 ❌
4 790 runs  4 790 ✅ 0 💤 0 ❌

Results for commit 5793756.

[github-actions]

Public API changes for crate: brush-core

Added items

+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::Error::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub fn brush_core::error::BuiltinError::as_io_error(&self) -> core::option::Option<&std::io::error::Error>
+pub brush_core::results::ExecutionExitCode::BrokenPipe
+impl core::convert::From<&std::io::error::Error> for brush_core::results::ExecutionExitCode
+impl core::convert::From<&std::io::error::Error> for brush_core::results::ExecutionExitCode
+pub fn brush_core::results::ExecutionExitCode::from(io_err: &std::io::error::Error) -> Self
+pub fn brush_core::results::ExecutionExitCode::from(io_err: &std::io::error::Error) -> Self
+pub brush_core::ExecutionExitCode::BrokenPipe
+pub fn brush_core::BuiltinError::as_io_error(&self) -> core::option::Option<&std::io::error::Error>

Performance Benchmark Report

Benchmark name	Baseline (μs)	Test/PR (μs)	Delta (μs)	Delta %
clone_shell_object	16.79 μs	16.78 μs	-0.01 μs	⚪ Unchanged
eval_arithmetic	0.15 μs	0.15 μs	-0.00 μs	⚪ Unchanged
expand_one_string	1.59 μs	1.61 μs	0.02 μs	⚪ Unchanged
for_loop	23.04 μs	22.90 μs	-0.14 μs	⚪ Unchanged
function_call	2.28 μs	2.13 μs	-0.15 μs	⚪ Unchanged
instantiate_shell	50.89 μs	51.80 μs	0.91 μs	🟠 +1.78%
instantiate_shell_with_init_scripts	25738.07 μs	24824.92 μs	-913.15 μs	🟢 -3.55%
parse_bash_completion	2054.83 μs	2020.02 μs	-34.81 μs	🟢 -1.69%
parse_sample_script	1.94 μs	1.94 μs	-0.01 μs	⚪ Unchanged
run_echo_builtin_command	15.60 μs	15.74 μs	0.14 μs	⚪ Unchanged
tokenize_sample_script	3.46 μs	3.50 μs	0.04 μs	⚪ Unchanged

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
brush-builtins/src/alias.rs	🟠 73.91%	🟢 77.27%	🟢 3.36%
brush-builtins/src/bind.rs	🟢 81.76%	🟢 84.41%	🟢 2.65%
brush-builtins/src/complete.rs	🟢 83.38%	🟢 83.33%	🔴 -0.05%
brush-builtins/src/declare.rs	🟢 86.13%	🟢 85.98%	🔴 -0.15%
brush-builtins/src/hash.rs	🟢 92.73%	🟢 92.45%	🔴 -0.28%
brush-builtins/src/help.rs	🟢 89.66%	🟢 89.53%	🔴 -0.13%
brush-builtins/src/history.rs	🟢 89.15%	🟢 89.06%	🔴 -0.09%
brush-builtins/src/kill.rs	🟠 51.69%	🟠 54.76%	🟢 3.07%
brush-builtins/src/printf.rs	🟢 92.16%	🟢 93.2%	🟢 1.04%
brush-builtins/src/read.rs	🟢 91.53%	🟢 91.5%	🔴 -0.03%
brush-builtins/src/return_.rs	🟢 94.12%	🟢 93.75%	🔴 -0.37%
brush-builtins/src/set.rs	🟢 77.63%	🟢 77.53%	🔴 -0.1%
brush-builtins/src/shopt.rs	🟢 75.9%	🟢 77.22%	🟢 1.32%
brush-builtins/src/times.rs	🟢 90.48%	🟢 89.47%	🔴 -1.01%
brush-builtins/src/trap.rs	🟢 83.82%	🟢 83.58%	🔴 -0.24%
brush-builtins/src/type_.rs	🟢 83.76%	🟢 83.48%	🔴 -0.28%
brush-builtins/src/ulimit.rs	🟠 66.45%	🟠 66.67%	🟢 0.22%
brush-builtins/src/unalias.rs	🟢 83.33%	🟢 82.35%	🔴 -0.98%
brush-core/src/commands.rs	🟢 91.48%	🟢 91.79%	🟢 0.31%
brush-core/src/error.rs	🟢 88.14%	🟢 90.91%	🟢 2.77%
brush-core/src/expansion.rs	🟢 94.31%	🟢 94.23%	🔴 -0.08%
brush-core/src/extendedtests.rs	🟠 73.99%	🟠 74.75%	🟢 0.76%
brush-core/src/jobs.rs	🟠 51.38%	🟠 51.61%	🟢 0.23%
brush-core/src/results.rs	🟢 79.84%	🟢 79.37%	🔴 -0.47%
brush-core/src/wellknownvars.rs	🟢 83.94%	🟢 83.9%	🔴 -0.04%
brush-interactive/src/basic/term_line_reader.rs	🔴 38.14%	🔴 38.74%	🟢 0.6%
brush-interactive/src/interactive_shell.rs	🟠 63.4%	🟠 63.95%	🟢 0.55%
brush-parser/src/ast.rs	🔴 44.99%	🔴 45.09%	🟢 0.1%
brush-parser/src/parser/peg.rs	🟢 95.89%	🟢 96.16%	🟢 0.27%
brush-parser/src/test_command.rs	🟢 83.58%	🟢 85.07%	🟢 1.49%
brush-parser/src/tokenizer.rs	🟢 93.24%	🟢 93.46%	🟢 0.22%
brush-test-harness/src/execution.rs	🟢 80.75%	🟢 79.14%	🔴 -1.61%
brush-test-harness/src/reporting.rs	🔴 10.71%	🔴 11.62%	🟢 0.91%
brush-test-harness/src/runner.rs	🟢 82.51%	🟢 82.41%	🔴 -0.1%
xtask/src/common.rs	🟠 51.11%	🟠 52.27%	🟢 1.16%
Overall Coverage	🟢 74.66%	🟢 74.88%	🟢 0.22%

Minimum allowed coverage is 70%, this run produced 74.88%

Test Summary: bash-completion test suite

Outcome	Count	Percentage
✅ Pass	1558	73.87
❗️ Error	18	0.85
❌ Fail	179	8.49
⏩ Skip	339	16.07
❎ Expected Fail	13	0.62
✔️ Unexpected Pass	2	0.09
📊 Total	2109	100.00

[Copilot]

Pull request overview

This PR standardizes how broken pipe (SIGPIPE) conditions from builtins are handled, ensuring they translate into the expected exit status (141) and do not surface as fatal or noisy errors in pipelines.

Changes:

• Add a dedicated ExecutionExitCode::BrokenPipe variant and wire it into exit-code conversions, including from std::io::Error.
• Extend the builtin error infrastructure (BuiltinError and Error) to expose underlying std::io::Errors so broken pipe causes can be detected centrally in execute_builtin_command.
• Update printf to propagate I/O errors directly and add compat test cases to validate broken pipe behavior in pipelines and PIPESTATUS.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
brush-shell/tests/cases/compat/pipeline.yaml	Unskips a previously TODO’d broken-pipe case and adds a new printf pipeline test to assert exit code 141 and correct PIPESTATUS.
brush-core/src/results.rs	Introduces ExecutionExitCode::BrokenPipe and maps it to/from numeric code 141, integrating SIGPIPE into the unified exit-code model.
brush-core/src/error.rs	Enhances the error model with BuiltinError::as_io_error, Error::as_io_error, and an impl From<&std::io::Error> for ExecutionExitCode, so I/O errors (notably broken pipes) can be converted into appropriate exit codes.
brush-core/src/commands.rs	Adjusts builtin execution to intercept broken-pipe I/O errors, turning them into a normal ExecutionResult with exit code 141 instead of propagating a fatal or noisy error.
brush-builtins/src/printf.rs	Changes printf to propagate underlying I/O errors as brush_core::Error (rather than wrapping them as usage errors), allowing broken pipes from printf to be recognized and mapped to 141.