Running fuzzing tar test with [zig std lib
fuzzing](https://github.com/squeek502/zig-std-lib-fuzzing) reached and
assert in tar implementation. Assert (in std lib) should not be
reachable by external input, so I'm fixing this to return error.
If an adapted string key with embedded nulls was put in a hash map with
`std.hash_map.StringIndexAdapter`, then an incorrect hash would be
entered for that entry such that it is possible that when looking for
the exact key that matches the prefix of the original key up to the
first null would sometimes match this entry due to hash collisions and
sometimes not if performed later after a grow + rehash, causing the same
key to exist with two different indices breaking every string equality
comparison ever, for example claiming that a container type doesn't
contain a field because the field name string in the struct and the
string representing the identifier to lookup might be equal strings but
have different string indices. This could maybe be fixed by changing
`std.hash_map.StringIndexAdapter.hash` to only hash up to the first
null, therefore ensuring that the entry's hash is correct and that all
future lookups will be consistent, but I don't trust anything so instead
I assert that there are no embedded nulls.
BufferedTee provides reader interface to the consumer. Data read by consumer
is also written to the output. Output is hold lookahead_size bytes behind
consumer. Allowing consumer to put back some bytes to be read again. On flush
all consumed bytes are flushed to the output.
input -> tee -> consumer
|
output
input - underlying unbuffered reader
output - writer, receives data read by consumer
consumer - uses provided reader interface
If lookahead_size is zero output always has same bytes as consumer.
This introduces the new test step `test-c-import`, and removes the
ability of the behavior tests to `@cImport` paths relative to `test`.
This allows the behavior tests to be run without translate c.
This commit works around #18967 by adding an `AccumulatingReader`, which
accumulates data read from the underlying packfile, and by keeping track
of the position in the packfile and hash/checksum information separately
rather than using reader composition. That is, the packfile position and
hashes/checksums are updated with the accumulated read history data only
after we can determine what data has actually been used by the
decompressor rather than merely being buffered.
The only addition to the standard library APIs to support this change is
the `unreadBytes` function in `std.compress.flate.Inflate`, which allows
the user to determine how many bytes have been read only for buffering
and not used as part of compressed data.
These changes can be reverted if #18967 is resolved with a decompressor
that reads precisely only the number of bytes needed for decompression.
This code is run when printing a stack trace in a debug executable, so
it has to be fast even without compiler optimizations.
Adding a `@panic` to the top of `main` and running an x86_64 backend
compiled compiler goes from `1m32.773s` to `0m3.232s`.
