Prior to this fix, fish would invalidate the exported variable list
whenever an exported variable changes. However we soon will not have a
single "exported variable list." If a global variable changes, it is
infeasible to find all exported variable lists and invalidate them.
Switch to a new model where we store a list of generation counts. Every
time an exported variable changes, the node gets a new generation. If the
current generation list does not match the cached one, then we know that
our exported variable list is stale.
This makes the following changes:
1. Events in background threads are executed in those threads, instead of
being silently dropped
2. Blocked events are now per-parser instead of global
3. Events are posted in builtin_set instead of within the environment stack
The last one means that we no longer support event handlers for implicit
sets like (example) argv. Instead only the `set` builtin (and also `cd`)
post variable-change events.
Events from universal variable changes are still not fully rationalized.
Someone has hit the 10MiB limit (and of course it's the number of
javascript packages), and we don't handle it fantastically currently.
And even though you can't pass a variable of that size in one go, it's
plausible that someone might do it in multiple passes.
See #5267.
I noticed my debug output for 24bit color mode was garbled due to
this being wrong. I spent a little time trying to get the compiler
to tell us about these, but -Wformat doesn't do anything for wchar
printf functions, and __attribute__((format(printf, n, m))) will
cause an error with wchar_t's, so I gave up and decided to manually
check out every '%s' in the entire project. I found (only) one
more.
debug(0, "%s", wchars) will report warnings for incorrect
specifiers but debug(0, L"%s", wchars) is unable. Thus there may
be reason to prefer not using L"..." as an argument if all else
is equal and it's not necessary.
This runs build_tools/style.fish, which runs clang-format on C++, fish_indent on fish and (new) black on python.
If anything is wrong with the formatting, we should fix the tools, but automated formatting is worth it.
This new file is supposed to encapsulate all of the logic around
reacting to variable changes, as opposed to the environment core.
This is to help break up the env.cpp monolith.
