The library prefetch pool now cancels queued futures on interrupt like
the espidf pool it mirrors, prefetch and HEAD failures log their cause
at debug (a suppressed bar is traceable), and non-2xx HEAD statuses read
as unknown size. normalize_dependencies rejects a non-string version in
both spellings (a container would raise from set.add(); an int fails
opaquely in the registry), and the walk's version-less skip logs the
dependency at debug until the arduino-backend reconciliation lands.
The wave logged 'Downloading N libraries' before checking the
extraction markers, so a warm build announced downloads it never made.
URLSource gains an is_cached probe (best-effort in the prefetch) and a
fully warm wave stays silent.
Brings in #18513 (BatchDownloadProgress and the download_with_resume
progress callback) and extends the plumbing one level:
download_from_mirrors passes a progress callback to both target kinds,
Source/ConvertedLibrary.download thread it through, and the library
wave prefetch draws one combined bar sized by parallel HEAD requests
(no sizes, no bar). The thread-local bar suppression this replaces is
removed; a batch caller passing a tracker also owns the messaging, so
the per-file Downloading line only prints for solo downloads.
The walk now drains its frontier, prefetches the wave's registry
archives with a small thread pool (deduped by URL, progress bars
suppressed per thread since parallel bars would interleave), and then
processes the wave sequentially; the sequential download() call stays
authoritative so failures surface with resume exactly as before. Same
approach as the espidf tool prefetch in #18513.
The typed IncompatiblePlatform exception, dependency_is_usable,
warn_properties_depends, the lex_build_flags helper (espidf switches to
it), the normalize_dependencies validation, the manifest shape check,
the component-level drop-warning split, and the SCons case-sensitive
.C/.C++ suffixes all harden the shared converter independently of the
arduino backend, so they belong in this PR; the provides hook and the
version-less reconciliation stay with the backend that needs them.
J. Nick Koston