[hotfix] Add help handling to build script

[kaiwangleo]

Linked issue: N/A (hotfix)

Purpose of change

Add -h/--help handling to tools/build.sh and show usage for unknown options instead of failing because show_help is undefined.

Tests

• Added tools/test/integration/build_help.bats covering --help, -h, and unknown options.
• Manually verified bash tools/build.sh --help, bash tools/build.sh -h, and bash tools/build.sh --no-such-option (Bats is not installed locally).

API

No public API changes.

Documentation

• doc-needed
• doc-not-needed
• doc-included

[weiqingy]

Thanks for taking this on. One question inline, nothing blocking.

[weiqingy]

nit: -ne 0 passes whether the script is broken or fixed. On main this path exits 127, and with your fix it exits 1, so both satisfy the check. I tried changing the *) branch to exit 2 locally and all three tests still passed, so nothing here locks in the exit code your fix actually produces. The test does still go red against main, just through the Usage: check below it, so it is doing its job.

Would [ "$status" -eq 1 ] be worth using instead? That would say an unknown option is a usage error rather than a crash. Curious whether you left it loose on purpose.

[kaiwangleo]

Updated in commit 3605821: the unknown-option regression test now asserts the expected usage-error exit code with [ $status -eq 1 ]. The focused Bats test passes.

[kaiwangleo]

Thanks for pointing this out. I left the assertion broad initially because the test only needed to verify that an unknown option failed, regardless of the specific non-zero status. However, since tools/build.sh treats unknown options as usage errors and explicitly exits with status 1, asserting [ $status -eq 1 ] makes the expected behavior clearer and prevents unrelated failures such as exit code 127 from satisfying the test. I’ve updated the test in commit 3605821f; the focused Bats tests pass.