A refresh blocked on a data directory lock printed only that another
run held it, then waited with no limit. The line now names the lock
file and the lsof command that shows its holder, and for a refresh,
the generate_pack --no-refresh-data and --offline runs that read the
cache without waiting.
generate_pack refreshed the data directories before probing its output
lock. The refresh waits for every run holding a tree, and a pipeline holds
them all: a second build sat silent for hours instead of being refused.
The output lock is now taken first, and a refresh that has to wait for a
tree names it.
refresh_data_dirs printed one line per entry and no total, a dry run named
the cached tag only, and cutting a quoted ETag at 12 characters kept one
quote. The run now ends on refreshed / up to date / failed counts, a dry
run shows the remote tag beside the cached one, and tags lose their quotes
before they are cut.
Abdessamad Derraz