PR #2183: fix year overflow on leap-second carry in ParseCivilTime Imported from GitHub PR https://github.com/abseil/abseil-cpp/pull/2183 ParseCivilTime parses the year on its own, normalises it into a small range around 2400 so the rest of the string can go through ParseTime, then rebuilds the result by adding the field-normalisation carry back onto the original year. The carry itself is small, but the year it is added to comes straight from the input, and at the largest representable year a trailing leap second rolls the value one past the maximum, so the addition overflows civil_year_t. It is reachable from untrusted text because the civil-time types parse flag and configuration strings through this path, and a value like 9223372036854775807-12-31T23:59:60 triggers it: a sanitiser build reports signed integer overflow at the carry, while an ordinary build silently wraps the year to the minimum and still returns success. I came across it while reading the carry handling that was added recently. Bounding the addition against the type limits and failing the parse when it would overflow leaves every normal year untouched and only rejects the few values that cannot be represented. I have added a regression case beside the existing carry test. Merge d9ba674d286e8bdd4614956842e1a30b00a0763b into 511e3f4b7ee50848e52dad3b054887e19def5ad8 Merging this change closes #2183 PiperOrigin-RevId: 999343915 Change-Id: Ic18834bda53fae4aa21e1f17de5fbeac3eb95ae0
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base base library contains initialization code and other code which all other Abseil code depends on. Code within base may not depend on any other code (other than the C++ standard library).algorithm algorithm library contains additions to the C++ <algorithm> library and container-based versions of such algorithms.cleanup cleanup library contains the control-flow-construct-like type absl::Cleanup which is used for executing a callback on scope exit.container container library contains additional STL-style containers, including Abseil's unordered “Swiss table” containers.crc The crc library contains code for computing error-detecting cyclic redundancy checks on data.debugging debugging library contains code useful for enabling leak checks, and stacktrace and symbolization utilities.flags flags library contains code for handling command line flags for libraries and binaries built with Abseil.hash hash library contains the hashing framework and default hash functor implementations for hashable types in Abseil.log log library contains LOG and CHECK macros and facilities for writing logged messages out to disk, stderr, or user-extensible destinations.memory memory library contains memory management facilities that augment C++'s <memory> library.meta meta library contains type checks similar to those available in the C++ <type_traits> library.numeric numeric library contains 128-bit integer types as well as implementations of C++20's bitwise math functions.profiling profiling library contains utility code for profiling C++ entities. It is currently a private dependency of other Abseil libraries.random random library contains functions for generating pseudorandom values.status status library contains abstractions for error handling, specifically absl::Status and absl::StatusOr<T>.strings strings library contains a variety of strings routines and utilities.synchronization synchronization library contains concurrency primitives (Abseil's absl::Mutex class, an alternative to std::mutex) and a variety of synchronization abstractions.time time library contains abstractions for computing with absolute points in time, durations of time, and formatting and parsing time within time zones.types types library contains non-container utility types.utility utility library contains utility and helper code.Abseil recommends users “live-at-head” (update to the latest commit from the master branch as often as possible). However, we realize this philosophy doesn't work for every project, so we also provide Long Term Support Releases to which we backport fixes for severe bugs. See our release management document for more details.
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