sccache 0.18.0

Summary

sccache 0.18.0 is a broad correctness and coverage release: a lot of compiler flags that used to
force a cache miss are now understood, several cache-key and multi-level storage bugs are fixed,
and the Azure backend gained passwordless authentication.

Highlights:

• Cache-key correctness: the assembler gcc/clang would actually invoke is now part of the cache
  key, so two toolchains with different binutils can no longer hand each other the wrong object
  file (#2843). SCCACHE_BASEDIRS now also strips base directories from the compiler arguments,
  so flags like -ffile-prefix-map=/home/user/project=. stop tying an entry to one checkout
  (#2840).
• MSVC/clang flag coverage: support for /openmp:llvm, the /fsanitize*, /fsanitize-coverage*
  and /fno-sanitize* families, /feature, arm64EC and fastfail, /d20bforceinline, and a large
  batch of other flags (#2807, #2830, #2831, #2832), plus more clang CLI options (#2834). gcc now
  marks flags as TooHard when they would require caching something else (#2833).
• CUDA: nvcc dryrun parsing works with CUDA 13.3 (#2722), escaped quotes in Windows dryrun
  lines are protected before backslash flattening (#2811), and the
  --diag-error/--diag-suppress/--diag-warn family is accepted (#2816).
• Multi-level cache: a chain with any writable level is writable again — a single read-only
  level no longer makes the whole storage read-only (#2778) — and reads are no longer issued twice
  (#2835).
• Azure: Microsoft Entra ID (passwordless) authentication for the Azure Blob backend, for
  storage accounts that disable shared-key access (#2802).
• Distributed compilation: rlibs are no longer trimmed from crates that also emit a cdylib,
  which made those jobs fail on the build server (#2839).
• Process handling: the jobserver is no longer handed to children that can't use it, which
  restores the posix_spawn fast path for child spawns (#2827), and daemonization now uses an
  allow-list for inherited file descriptors, fixing make deadlocks caused by leaked jobserver FDs
  (#2841).
• MSRV is now 1.91.0 (#2793).

Welcome to 11 new contributors!

Features

• feat: add Microsoft Entra ID (passwordless) auth for the Azure Blob backend by @babrekel in #2802
• gcc, clang: make the assembler part of the cache key by @glandium in #2843
• Strip basedirs from the compiler arguments too by @avikivity in #2840
• cache: allow skipping capability checks by @Xuanwo in #2822
• Optimize child process spawns by skipping job server configs by @rnk in #2827

Compiler support

• feat: add support for MSVC's /d20bforceinline. by @AJIOB in #2807
• msvc: support arm64EC and fastfail flags by @AJIOB in #2830
• msvc: backport flags support by @AJIOB in #2831
• msvc: support lots of flags by @AJIOB in #2832
• clang: support more CLI options by @AJIOB in #2834
• gcc: mark flags as TooHard if need to cache something else by @AJIOB in #2833
• nvcc: accept the --diag-error/--diag-suppress/--diag-warn family by @Kataglyphis in #2816

Fixes

• Fix nvcc dryrun parsing for CUDA 13.3 by @mbrobbel in #2722
• nvcc (Windows): protect escaped quotes in dryrun lines before flattening backslashes by @Kataglyphis in #2811
• multilevel: a chain with any writable level is writable by @tycho in #2778
• cache: avoid duplicate multilevel reads by @zfaustk in #2835
• Resolving always-false conditional making some compilers miss for preprocessor checks by @Joldiges in #2824
• dist: refuse to trim rlibs from crates that also emit a cdylib by @gaetschwartz in #2839
• daemonize: use an allow-list approach to inherited FDs by @schopin-mozilla in #2841

Dependencies

• Bump opendal to 0.58.1 and fix fallout (fixes local GCS cache usage) by @flip1995 in #2715
• Update shlex dependency to version 2 by @musicinmybrain in #2836
• Bump MSRV to 1.91.0 by @flip1995 in #2793

Tests & CI

• Fixed hardcoded binary path in test by @ranger-ross in #2790
• ci: dump sccache logs on integration failures by @JalenBuildsHub in #2851
• tests/integration: replace MinIO with Silo by @avikivity in #2853

Cleanup

• Add an agent file by @sylvestre in #2812
• chore: fix typo in comment by @AJIOB in #2829
• Release 0.18.0 by @sylvestre in #2848

New Contributors

• @mbrobbel made their first contribution in #2722
• @flip1995 made their first contribution in #2793
• @babrekel made their first contribution in #2802
• @Kataglyphis made their first contribution in #2811
• @schopin-mozilla made their first contribution in #2841
• @Joldiges made their first contribution in #2824
• @tycho made their first contribution in #2778
• @JalenBuildsHub made their first contribution in #2851
• @zfaustk made their first contribution in #2835
• @gaetschwartz made their first contribution in #2839
• @rnk made their first contribution in #2827

Full Changelog: v0.17.0...v0.18.0