Previously, the block stack was a true stack. However in most cases, you
want to traverse the stack from the topmost frame down. This is awkward
to do with range-based for loops.
Switch it to pushing new blocks to the front of the block list.
This simplifies some traversals.
This was previously required so that, if there was a redirection to a
file, we would fork a process to create the file even if there was no
output. For example `echo -n >/tmp/file.txt` would have to create
file.txt even though it would be empty.
However now we open the file before fork, so we no longer need special
logic around this.
Do this only when splitting on IFS characters which usually contains
whitespace characters --- read --delimiter is unchanged; it still
consumes no more than one delimiter per variable. This seems better,
because it allows arbitrary delimiters in the last field.
Fixes#6406
user_supplied was used to distinguish IO redirections which were
explicit, vs those that came about through "transmogrphication." But
transmogrification is no more. Remove the flag.
As of GCC 7.4 (at least under macOS 10.10), the previous workaround of
casting a must-use result to `(void)` to avoid warnings about unused
code no longer works.
This workaround is uglier but it quiets these warnings.
The C++ spec (as of C++17/n4713) does not specify the sign of `wchar_t`,
saying only (in section 6.7.1: Fundamental Types)
> Type wchar_t shall have the same size, signedness, and alignment
> requirements (6.6.5) as one of the other integral types, called its
> underlying type.
On most *nix platforms on AMD64 architecture, `wchar_t` is a signed type
and can be compared with `int32_t` without incident, but on at least
some platforms (tested: clang under FreeBSD 12.1 on AARCH64), `wchar_t`
appears to be unsigned leading to sign comparison warnings:
```
../src/widecharwidth/widechar_width.h:512:48: warning: comparison of
integers of different signs: 'const wchar_t' and 'int32_t' (aka 'int')
[-Wsign-compare]
return where != std::end(arr) && where->lo <= c;
```
This patch forces the use of wchar_t for the range start/end values in
`widechar_range` and the associated comparison values.
Previously, if the user control-C'd out of a process, we would set a
bogus exit status in the process, but it was difficult to observe this
because we would be cancelling anyways. But set it properly.
If a Control-C is received during expanding a command substitution, we
may execute the job anyways, because we do not check for cancellation
after the expansion. Ensure that does not happen.
This should fix sporadic test failures in the cancellation unit test.
parser_t::eval indicates whether there was a parse error. It can be
easily confused with the status of the execution. Use a real type to
make it more clear.
Looking up a variable by a string literal implicitly constructs a wcstring.
By avoiding that, we get a noticeable reduction of temporary allocations.
$ HOME=. heaptrack ./fish -c true
heaptrack stats: # baseline
allocations: 7635
leaked allocations: 3277
temporary allocations: 602
heaptrack stats: # new
allocations: 7565
leaked allocations: 3267
temporary allocations: 530
This adds a test for the obscure case where an fd is redirected to
itself. This is tricky because the dup2 will not clear the CLO_EXEC bit.
So do it manually; also posix_spawn can't be used in this case.
The IO cleanup left file redirections open in the child. For example,
/bin/cmd < file.txt would redirect stdin but also leave the file open.
Ensure these get closed properly.
Prior to this fix, a file redirection was turned into an io_file_t. This is
annoying because every place where we want to apply the redirection, we
might fail due to open() failing. Switch to opening the file at the point
we resolve the redirection spec. This will simplify a lot of code.
Prior to this change, a process after it has been constructed by
parse_execution, but before it is executed, was given a list of
io_data_t redirections. The problem is that redirections have a
sensitive ownership policy because they hold onto fds. This made it
rather hard to reason about fd lifetime.
Change these to redirection_spec_t. This is a textual description
of a redirection after expansion. It does not represent an open file and
so its lifetime is no longer important.
This enables files to be held only on the stack, and are no longer owned
by a process of indeterminate lifetime.
fish has to ensure that the pipes it creates do not conflict with any
explicit fds named in redirections. Switch this code to using
autoclose_fd_t to make the ownership logic more explicit, and also
introduce fd_set_t to reduce the dependence on io_chain_t.
Prior to this fix, a job would hold onto any IO redirections from its
parent. For example:
begin
echo a
end < file.txt
The "echo a" job would hold a reference to the I/O redirection.
The problem is that jobs then extend the life of pipes until the job is
cleaned up. This can prevent pipes from closing, leading to hangs.
Fix this by not storing the block IO; this ensures that jobs do not
prolong the life of pipes.
Fixes#6397
Currently a job needs to know three things about its "parents:"
1. Any IO redirections for the block or function containing this job
2. The pgid for the parent job
3. Whether the parent job has been fully constructed (to defer self-disown)
These are all tracked in somewhat separate awkward ways. Collapse them
into a single new type job_lineage_t.
