Fix Get Blob suffix range bytes=-1 500 on 1-byte blobs

[Joel Town Road (hippi345)]

Problem

Get Blob with a suffix range on a 1-byte block blob returned HTTP 500 instead of 206.

Range: bytes=-1 was parsed as start NaN, so Azurite logged NormalizedDownloadRange=bytes=NaN-0 and then threw a RangeError. Azure Storage returns 206 with the last byte (Content-Range: bytes 0-0/1).

Fixes #2856

Fix

• Parse HTTP suffix-byte-range-spec (bytes=-N with N > 0) in deserializeRangeHeader, opt-in for downloads only (allowSuffixRange defaults to false).
• Resolve suffix ranges against blob length in block, append, and page blob download before clamping.
• Page mutations (Clear Pages and Upload Pages) reject suffix/empty ranges with HTTP 416. Get Page Ranges does not: suffix and empty values (bytes=-1, bytes=-99, bytes=-0, bytes=-, bytes=, empty) keep the upstream 200 (empty PageList). Malformed values such as bytes=5-2 and garbage still return 416 rather than 500.
• bytes=-N (N > 0) on a 0-byte blob returns 416 with Content-Range: bytes */0 on both the block/append download path and the page blob download path.
• Invalid suffix/empty Range on page-blob Get Blob (bytes=-0, bytes=-, bytes=) is ignored like block and append blobs (HTTP 200, full body) instead of 500.
• Added an Upcoming Release entry in ChangeLog.md as required by this project's contribution guidelines.

Test helper: RangePolicyFactory sets only the Range header. InjectorPolicyFactory has its own policy that sets x-ms-range after SDK serialization, so existing Range-header tests still exercise the plain Range header.

Testing

Added coverage in tests/blob/apis/blob.test.ts and tests/blob/apis/pageblob.test.ts.

1-byte suffix download (unmodified upstream):

  BlobAPIs
    1) download suffix range bytes=-1 on a 1-byte blob @loki @sql


  0 passing (84ms)
  1 failing

  1) BlobAPIs
       download suffix range bytes=-1 on a 1-byte blob @loki @sql:
     RestError
      at handleErrorResponse (node_modules/@azure/core-client/src/deserializationPolicy.ts:255:17)
      at deserializeResponseBody (node_modules/@azure/core-client/src/deserializationPolicy.ts:159:43)
      at processTicksAndRejections (node:internal/process/task_queues:105:5)

After the download suffix fix (nearby download/range tests):

  BlobAPIs
    ✔ download all parameters set @loki @sql
    ✔ download entire with range @loki @sql
    ✔ download out of range @loki @sql
    ✔ download invalid range @loki @sql
    ✔ download partial range (via custom policy) @loki @sql
    ✔ download suffix range bytes=-1 on a 1-byte blob @loki @sql


  6 passing (122ms)

0-byte suffix download and page-mutation suffix ranges (on 43914f2):

  0 passing (122ms)
  4 failing
  (0-byte downloads returned 206; populated clearPages returned 500; empty-map clearPages succeeded)

After opt-in suffix parsing and 0-byte 416:

  4 passing (109ms)

Get Page Ranges and page-blob invalid Range (on d111d92, before this commit):

  PageBlobAPIs
    1) download ignores invalid suffix and empty Range like block blobs @loki
    2) getPageRanges returns 200 for suffix or empty x-ms-range and 416 for malformed @loki


  0 passing (75ms)
  2 failing

  1) RestError  (page-blob Get Blob 500 for bytes=-0 / bytes=- / bytes=)

  2) RestError: The page range specified is invalid.
     (Get Page Ranges 416 for bytes=-1; upstream is 200)

After restoring Get Page Ranges 200 and ignoring invalid page-blob download ranges:

  PageBlobAPIs
    ✔ download ignores invalid suffix and empty Range like block blobs @loki
    ✔ download suffix range bytes=-1 on a 0-byte page blob returns 416 @loki
    ✔ clearPages with suffix range bytes=-512 on a populated page map returns 416 @loki
    ✔ clearPages with suffix range bytes=-512 on an empty page map returns 416 @loki
    ✔ getPageRanges returns 200 for suffix or empty x-ms-range and 416 for malformed @loki

  BlobAPIs
    ✔ download suffix range bytes=-1 on a 1-byte blob @loki @sql
    ✔ download suffix range bytes=-1 on a 0-byte blob returns 416 @loki @sql


  7 passing (153ms)

loki suites (blob, pageblob, appendblob, blockblob, container, conditions) plus lint and tsc:

eslint src/**/*.ts  (exit 0)
tsc -p .            (exit 0)

  372 passing (2m)
  3 pending

utils suite (no @loki tags):

  16 passing (11ms)

This change was prepared with AI assistance. I remain responsible for the contribution and have reviewed it.

[Copilot]

🟡 Changes recommended

Page-clear requests can regress to HTTP 500, and empty-blob suffix downloads produce invalid partial responses.

2 open issues

• Reject suffix ranges in page-mutation validation · New
• Reject unsatisfiable suffix ranges on empty blobs · New

What changed in this PR

Fixes suffix-range Get Blob downloads for issue #2856, including the one-byte bytes=-1 failure.

Changes:

• Parses suffix ranges and resolves them against block, append, and page blob lengths.
• Adds a one-byte download regression test.
• Documents the fix in the upcoming release notes.

File	Description
tests/​blob/​apis/​blob.test.ts	Adds the one-byte suffix-range regression test.
src/​blob/​utils/​utils.ts	Adds suffix parsing and range resolution.
src/​blob/​handlers/​BlobHandler.ts	Resolves suffix ranges before download clamping.
ChangeLog.md	Records the user-visible fix.

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

Range validation still allows malformed suffixes and introduces an unhandled error in Get Page Ranges.

1 open issue

• Handle invalid page range errors in getPageRanges · New

1 previously missed issue

In code that hasn't changed since last review

Reject malformed suffix lengths instead of using parseInt

src/​blob/​utils/​utils.ts:239

Validate the entire suffix length before accepting it. parseInt accepts malformed headers such as bytes=-1oops and bytes=-1,2 as one-byte suffixes, so a block blob containing abcdef returns 206 with f instead of reaching the existing invalid-range handling. Require decimal digits only, and add malformed-suffix regression cases.

2 resolved since last review

• Reject unsatisfiable suffix ranges on empty blobs
• Reject suffix ranges in page-mutation validation

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Malformed suffixes are accepted as valid partial-download ranges instead of following invalid-range handling.

1 open issue

• Handle invalid page range errors in getPageRanges

1 previously missed issue

In code that hasn't changed since last review

Reject malformed suffix ranges with trailing or fractional characters

src/​blob/​utils/​utils.ts:239

parseInt accepts numeric prefixes, so malformed suffixes such as bytes=-3oops and bytes=-3.5 become valid three-byte ranges and are served as HTTP 206. Validate that the entire suffix contains decimal digits before accepting it, so these headers follow the existing invalid-range handling instead of silently selecting a different range.

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Malformed suffixes still produce partial responses instead of using the invalid-range fallback.

No open issues 🎉

2 previously missed issues

In code that hasn't changed since last review

Reject malformed suffix ranges instead of truncating with parseInt

src/​blob/​utils/​utils.ts:231

Malformed suffixes such as bytes=-1.5 and bytes=-1junk are accepted as bytes=-1 because parseInt stops at the first non-digit. Both download paths then return 206 with the last byte rather than using their invalid-range fallback (200 with the full blob). Validate the entire suffix as decimal digits before parsing, and add regression cases for these inputs.

Add multi-byte suffix download tests for exact ranges and clamping

src/​blob/​utils/​utils.ts:287

The only successful suffix-download test uses a one-byte blob, so it cannot detect a resolver that always returns the whole blob. Add successful downloads with distinguishable multi-byte content for block, append, and populated page blobs. Cover suffix lengths smaller than and larger than the blob length, asserting the exact body, 206 status, and Content-Range to verify both offset calculation and clamping.

1 resolved since last review

• Handle invalid page range errors in getPageRanges

_{Review effort: Balanced}