It used to error out when a command wasn't known, even when it was a
function that would only be discovered via autoloading.
Now we just accept that a command doesn't exist when no-execute is
given - we're not gonna execute it anyway.
Also, in the same breath stop counting empty commands after expansion
and empty wildcard expansions as errors - these depend on runtime
values, so we can't verify them without executing.
Fixes#977.
(note that it still executes "time", but that's another commit)
The `function --on-job-exit caller` feature allows a command substitution
to observe when the parent job exits. This has never worked very well - in
particular it is based on job IDs, so a function that observes this will
run multiple times. Implement it properly.
Do this by having a not-recycled "internal job id".
This is only used by psub, but ensure it works properly none-the-less.
Introduce pgroup_provenance_t, a type which captures "where the pgroup
comes from." This centralizes some logic around how pgroups are
assigned, and it anticipates concurrent execution.
Prior to this fix, fish was rather inconsistent in when $status gets set
in response to an error. For example, a failed expansion like "$foo["
would not modify $status.
This makes the following inter-related changes:
1. String expansion now directly returns the value to set for $status on
error. The value is always used.
2. parser_t::eval() now directly returns the proc_status_t, which cleans
up a lot of call sites.
3. We expose a new function exec_subshell_for_expand() which ignores
$status but returns errors specifically related to subshell expansion.
4. We reify the notion of "expansion breaking" errors. These include
command-not-found, expand syntax errors, and others.
The upshot is we are more consistent about always setting $status on
errors.
This commit recognizes an existing pattern: many operations need some
combination of a set of variables, a way to detect cancellation, and
sometimes a parser. For example, tab completion needs a parser to execute
custom completions, the variable set, should cancel on SIGINT. Background
autosuggestions don't need a parser, but they do need the variables and
should cancel if the user types something new. Etc.
This introduces a new triple operation_context_t that wraps these concepts
up. This simplifies many method signatures and argument passing.
for-loops that were not inside a function could overwrite global
and universal variables with the loop variable. Avoid this by making
for-loop-variables local variables in their enclosing scope.
This means that if someone does:
set a global
for a in local; end
echo $a
The local $a will shadow the global one (but not be visible in child
scopes). Which is surprising, but less dangerous than the previous
behavior.
The detection whether the loop is running inside a function was failing
inside command substitutions. Remove this special handling of functions
alltogether, it's not needed anymore.
Fixes#6480
Store the entire function declaration, not just its job list.
This allows us to extract the body of the function complete with any
leading comments and indents.
Fixes#5285
In particular, this allows `true && time true`, or `true; and time true`,
and both `time not true` as well as `not time true` (like bash).
time is valid only as job _prefix_, so `true | time true` could call
`/bin/time` (same in bash)
See discussion in #6442
This PR is aimed at improving how job ids are assigned. In particular,
previous to this commit, a job id would be consumed by functions (and
thus aliases). Since it's usual to use functions as command wrappers
this results in awkward job id assignments.
For example if the user is like me and just made the jump from vim -> neovim
then the user might create the following alias:
```
alias vim=nvim
```
Previous to this commit if the user ran `vim` after setting up this
alias, backgrounded (^Z) and ran `jobs` then the output might be:
```
Job Group State Command
2 60267 stopped nvim $argv
```
If the user subsequently opened another vim (nvim) session, backgrounded
and ran jobs then they might see what follows:
```
Job Group State Command
4 70542 stopped nvim $argv
2 60267 stopped nvim $argv
```
These job ids feel unnatural, especially when transitioning away from
e.g. bash where job ids are sequentially incremented (and aliases/functions
don't consume a job id).
See #6053 for more details.
As @ridiculousfish pointed out in
https://github.com/fish-shell/fish-shell/issues/6053#issuecomment-559899400,
we want to elide a job's job id if it corresponds to a single function in the
foreground. This translates to the following prerequisites:
- A job must correspond to a single process (i.e. the job continuation
must be empty)
- A job must be in the foreground (i.e. `&` wasn't appended)
- The job's single process must resolve to a function invocation
If all of these conditions are true then we should mark a job as
"internal" and somehow remove it from consideration when any
infrastructure tries to interact with jobs / job ids.
I saw two paths to implement these requirements:
- At the time of job creation calculate whether or not a job is
"internal" and use a separate list of job ids to track their ids.
Additionally introduce a new flag denoting that a job is internal so
that e.g. `jobs` doesn't list internal jobs
- I started implementing this route but quickly realized I was
computing the same information that would be computed later on (e.g.
"is this job a single process" and "is this jobs statement a
function"). Specifically I was computing data that populate_job_process
would end up computing later anyway. Additionally this added some
weird complexities to the job system (after the change there were two
job id lists AND an additional flag that had to be taken into
consideration)
- Once a function is about to be executed we release the current jobs
job id if the prerequisites are satisfied (which at this point have
been fully computed).
- I opted for this solution since it seems cleaner. In this
implementation "releasing a job id" is done by both calling
`release_job_id` and by marking the internal job_id member variable to
-1. The former operation allows subsequent child jobs to reuse that
same job id (so e.g. the situation described in Motivation doesn't
occur), and the latter ensures that no other job / job id
infrastructure will interact with these jobs because valid jobs have
positive job ids. The second operation causes job_id to become
non-const which leads to the list of code changes outside of `exec.c`
(i.e. a codemod from `job_t::job_id` -> `job_t::job_id()` and moving the
old member variable to a non-const private `job_t::job_id_`)
Note: Its very possible I missed something and setting the job id to -1
will break some other infrastructure, please let me know if so!
I tried to run `make/ninja lint`, but a bunch of non-relevant issues
appeared (e.g. `fatal error: 'config.h' file not found`). I did
successfully clang-format (`git clang-format -f`) and run tests, though.
This PR closes#6053.
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.
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.
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.
This adds initial support for statements with prefixed variable assignments.
Statments like this are supported:
a=1 b=$a echo $b # outputs 1
Just like in other shells, the left-hand side of each assignment must
be a valid variable identifier (no quoting/escaping). Array indexing
(PATH[1]=/bin ls $PATH) is *not* yet supported, but can be added fairly
easily.
The right hand side may be any valid string token, like a command
substitution, or a brace expansion.
Since `a=* foo` is equivalent to `begin set -lx a *; foo; end`,
the assignment, like `set`, uses nullglob behavior, e.g. below command
can safely be used to check if a directory is empty.
x=/nothing/{,.}* test (count $x) -eq 0
Generic file completion is done after the equal sign, so for example
pressing tab after something like `HOME=/` completes files in the
root directory
Subcommand completion works, so something like
`GIT_DIR=repo.git and command git ` correctly calls git completions
(but the git completion does not use the variable as of now).
The variable assignment is highlighted like an argument.
Closes#6048
This adds support for `fish_trace`, a new variable intended to serve the
same purpose as `set -x` as in bash. Setting this variable to anything
non-empty causes execution to be traced. In the future we may give more
specific meaning to the value of the variable.
The user's prompt is not traced unless you run it explicitly. Events are
also not traced because it is noisy; however autoloading is.
Fixes#3427
Meaning empty variables, command substitutions that don't print
anything.
A switch without an argument
```fish
switch
case ...
end
```
is still a syntax error, and more than one argument is still a runtime
error.
The none-argument matches either an empty-string `case ''` or a
catch-all `case '*'`.
Fixes#5677.
Fixes#4943.
Previously when propagating explicitly separated output, we would early-out
if the buffer was empty, where empty meant contains no characters. However
it may contain one or more empty strings, in which case we should propagate
those strings.
Remove this footgun "empty" function and handle this properly.
Fixes#5987
We used to have a global notion of "is the shell interactive" but soon we
will want to have multiple independent execution threads, only some of
which may be interactive. Start tracking this data per-parser.
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.
This widens the remaining ones that don't take a char
anywhere.
The rest either use a char _variable_ or __FUNCTION__, which from my
reading is narrow and needs to be widened manually. I've been unable
to test it, though.
See #5900.
These were inadvertently disabled by a bug which was introduced in
cd7e8f4103 . Fix the bug so the tests run
again.
They don't all pass yet; they regressed during the period they were
disabled.
Blocks will soon need to be shared across parsers. Migrate the loop status
(like break or continue) from the block into the libdata. It turns out we
only ever need one, we don't need to track this per-block.
Make it an enum class.
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.
It was unconditionally returning `parse_execution_success`. This was
causing certain parser errors to incorrectly return after evaluation
with `$status` equal to `0`, as reported after `eval`, `source`, or
sub-`fish` execution.
Prior to this change, fish used a global flag to decide if we should check
for changes to universal variables. This flag was then checked at arbitrary
locations, potentially triggering variable updates and event handlers for
those updates; this was very hard to reason about.
Switch to triggering a universal variable update at a fixed location,
after running an external command. The common case is that the variable
file has not changed, which we can identify with just a stat() call, so
this is pretty cheap.
I did not realize builtins could safely call into the parser and inject
jobs during execution. This is much cleaner than hacking around the
required shape of a plain_statement.
`eval` has always been implemented as a function, which was always a bit
of a hack that caused some issues such as triggering the creation of a
new scope. This turns `eval` into a decorator.
The scoping issues with eval prevented it from being usable to actually
implement other shell components in fish script, such as the problems
described in #4442, which should now no longer be the case.
Closes#4443.
Followup to 394623b.
Doing it in the parser meant only top-level jobs would be reaped after
being `disown`ed, as subjobs aren't directly handled by the parser.
This is also much cleaner, as now job removal is centralized in
`process_clean_after_marking()`.
Closes#5803.
This prevents the `disown` builtin from directly removing jobs out of
the jobs list to prevent sanity issues, as `disown` may be called within
the context of a subjob (e.g. in a function or block) in which case the
parent job might not yet be done with the reference to the child job.
Instead, a flag is set and the parser removes the job from the list only
after the entire execution chain has completed.
Closes#5720.
Directly access the job list without the intermediate job_iterator_t,
and remove functions that are ripe for abuse by modifying a local
enumeration of the same list instead of operating on the iterators
directly (e.g. proc.cpp iterates jobs, and mid-iteration calls
parser::job_remove(j) with the job (and not the iterator to the job),
causing an invisible invalidation of the pre-existing local iterators.
