fix(downloader): validate partial download responses and sizes

[rtuszik]

closes #376

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Reviewing files that changed from the base of the PR and between e13fdc8 and a4d4ca9.

📒 Files selected for processing (2)

• src/downloader.py
• tests/test_downloader.py

🚧 Files skipped from review as they are similar to previous changes (2)

• src/downloader.py
• tests/test_downloader.py

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📝 Walkthrough

Walkthrough

The downloader now validates partial response headers and received sizes. It handles 416 resume responses by clearing state and retrying from byte zero. Tests cover valid resume responses, invalid ranges, oversized bodies, and retry limits.

Changes

Downloader resume validation and retry handling

Layer / File(s)	Summary
Response range and size validation src/downloader.py, tests/test_downloader.py	206 responses require valid case-insensitive Content-Range and matching Content-Length values. Negative lengths, oversized chunks, and incomplete final sizes are rejected. Tests cover invalid headers and oversized responses.
Resume status and retry handling src/downloader.py, tests/test_downloader.py	416 responses clear download state and trigger retry handling. Unexpected statuses are rejected. 200 responses restart resumed downloads. Tests cover 200 and 206 responses and retry limits.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to a4d4c

No concrete merge-blocking risk is identified in the supplied evidence.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarises the main change: validation of partial download responses and file sizes in the downloader.
Description check	✅ Passed	The description references issue #376, which relates to the downloader validation changes. This is sufficient for the lenient description check.
Linked Issues check	✅ Passed	Issue #376 requires resumed downloads from the saved offset, no duplicate appended data, enforcement of the planned file size, and handling of invalid range responses. src/downloader.py validates pa…
Out of Scope Changes check	✅ Passed	The changes are limited to download resume and response-size validation in src/downloader.py, with related automated tests in tests/test_downloader.py. The changes directly support issue #376. No …

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[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
src
downloader.py	260	19	93%	97–98, 205, 232–233, 250, 263–274, 277–278, 317, 380
importer.py	57	2	96%	19, 30
index.py	103	1	99%	145
process_manager.py	254	13	95%	155–156, 207–208, 232, 274–275, 284–286, 357–359
update.py	131	2	98%	93, 172
src/jsonl
decompressor.py	5	3	40%	5–7
downloader.py	31	14	55%	14, 18, 23, 25, 32–46
src/utils
config.py	55	3	95%	71–73
regions.py	105	8	92%	407, 420, 428, 432, 435, 448, 459, 474
validate_config.py	50	4	92%	33, 35, 41–42
TOTAL	1280	69	95%

Tests	Skipped	Failures	Errors	Time
291	0 💤	0 ❌	0 🔥	1.781s ⏱️

[coderabbitai]

Actionable comments posted: 1

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: fbb58428-603e-4e1b-88f1-7da0cbef99d7

📥 Commits

Reviewing files that changed from the base of the PR and between 15c8c62 and e13fdc8.

📒 Files selected for processing (2)

• src/downloader.py
• tests/test_downloader.py

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.