Fix a potential out of bounds read when building a XbBuilderNode

[hughsie]

Although xb_builder_node_set_text() is normally NUL-terminated, it doesn't have to be. Split the string taking into account the possibility that NUL is missing.

Found by Aisle Research, many thanks.

Summary by CodeRabbit

• Bug Fixes

  • Improved handling of length-limited text input, including buffers that are not NUL-terminated.
  • Preserved embedded newline content when processing builder-node text.

• Tests

  • Added coverage for zero-length input, NUL-terminated strings and embedded newline data.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: f401b788-1e2b-4eeb-a090-b541878f2394

📥 Commits

Reviewing files that changed from the base of the PR and between d8959ba and 158237c.

📒 Files selected for processing (4)

• src/xb-builder-node.c
• src/xb-common-private.h
• src/xb-common.c
• src/xb-self-test.c

🚧 Files skipped from review as they are similar to previous changes (4)

• src/xb-common.c
• src/xb-common-private.h
• src/xb-builder-node.c
• src/xb-self-test.c

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📝 Walkthrough

Walkthrough

The change adds xb_strsplit() for length-bounded input processing. Builder-node text splitting now uses the safe text length. Tests cover zero-length, NUL-terminated, and explicitly sized buffers.

Changes

Bounded text splitting

Layer / File(s)	Summary
Common split helper src/xb-common-private.h, src/xb-common.c	Adds xb_strsplit() with input validation and duplication for bounded data without a terminating NUL.
Builder-node integration and tests src/xb-builder-node.c, src/xb-self-test.c	Uses xb_strsplit() with text_len_safe and adds builder-node tests for zero-length, NUL-terminated, and explicitly sized input.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 28.57% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: preventing an out-of-bounds read in XbBuilderNode construction.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/xb-self-test.c`:
- Around line 2698-2707: The xb_builder_node_nul_func test does not verify the
text set on root. After each xb_builder_node_set_text call, read back or export
the node and assert the expected result, including the explicitly sized A\nB
buffer case; retain coverage for the zero-length input without treating it as
xb_strsplit coverage.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 3c491036-51a6-4520-a3a8-40bcbeccec3e

📥 Commits

Reviewing files that changed from the base of the PR and between 9366f7e and d8959ba.

📒 Files selected for processing (4)

• src/xb-builder-node.c
• src/xb-common-private.h
• src/xb-common.c
• src/xb-self-test.c

[hughsie]

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