[andypost]

msgpack_unserialize_uint64() is meant to return a float for uint64 values above ZEND_LONG_MAX that a double still represents exactly (up to 2^52), and a decimal string beyond that (#67, fb746e0):

} else if (data <= 1L<<52) {
    ZVAL_DOUBLE(*obj, data);

On 32-bit, long is 32 bits, so 1L<<52 is undefined behaviour. Every 32-bit build warns about it:

msgpack_unpack.c:440:26: warning: left shift count >= width of type [-Wshift-count-overflow]

In practice the float branch is never taken on 32-bit. Every uint64 above 2^31 comes back as a string. On i386 with PHP 8.5 and current master:

2^31 -> string(10) "2147483648"
2^32 -> string(10) "4294967296"
2^40 -> string(13) "1099511627776"
2^52 -> string(16) "4503599627370496"

On 64-bit the branch can't be reached anyway, since 2^52 < ZEND_LONG_MAX, so 32-bit is the only platform where the float range exists.

The fix computes the bound as (uint64_t) 1 << 52. The new test issue067_32bit_double.phpt (32-bit only) covers 2^31, 2^32 and 2^52 → float, and 2^52+1 → string. The existing issue067_32bit.phpt (values ≥ 2^63 → string) is unchanged.

Behaviour change on 32-bit: values from 2^31 to 2^52 now unpack as float, as the code intended, instead of string. Values above 2^52 are unchanged.

Verification

	i386 (PHP 8.5, Alpine edge)	x86_64
master	shift warning; new test FAILs; 141 passed / 1 failed	141 passed / 0 failed (new test skipped)
this PR	no warning; 142 passed / 0 failed	141 passed / 0 failed (new test skipped)

Found while fixing 32-bit issues for Alpine (alpine/aports!111139, see also #192 and #193).

🤖 Generated with Claude Code

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 68.65%. Comparing base (26c8c70) to head (f3a78df).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
msgpack_unpack.c	0.00%	0 Missing and 1 partial ⚠️
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #194   +/-   ##
=======================================
  Coverage   68.65%   68.65%           
=======================================
  Files           7        7           
  Lines        1356     1356           
  Branches      248      248           
=======================================
  Hits          931      931           
  Misses        310      310           
  Partials      115      115           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.