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4 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Ian Manske
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b6c7656194
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IO and redirection overhaul (#11934)
# Description The PR overhauls how IO redirection is handled, allowing more explicit and fine-grain control over `stdout` and `stderr` output as well as more efficient IO and piping. To summarize the changes in this PR: - Added a new `IoStream` type to indicate the intended destination for a pipeline element's `stdout` and `stderr`. - The `stdout` and `stderr` `IoStream`s are stored in the `Stack` and to avoid adding 6 additional arguments to every eval function and `Command::run`. The `stdout` and `stderr` streams can be temporarily overwritten through functions on `Stack` and these functions will return a guard that restores the original `stdout` and `stderr` when dropped. - In the AST, redirections are now directly part of a `PipelineElement` as a `Option<Redirection>` field instead of having multiple different `PipelineElement` enum variants for each kind of redirection. This required changes to the parser, mainly in `lite_parser.rs`. - `Command`s can also set a `IoStream` override/redirection which will apply to the previous command in the pipeline. This is used, for example, in `ignore` to allow the previous external command to have its stdout redirected to `Stdio::null()` at spawn time. In contrast, the current implementation has to create an os pipe and manually consume the output on nushell's side. File and pipe redirections (`o>`, `e>`, `e>|`, etc.) have precedence over overrides from commands. This PR improves piping and IO speed, partially addressing #10763. Using the `throughput` command from that issue, this PR gives the following speedup on my setup for the commands below: | Command | Before (MB/s) | After (MB/s) | Bash (MB/s) | | --------------------------- | -------------:| ------------:| -----------:| | `throughput o> /dev/null` | 1169 | 52938 | 54305 | | `throughput \| ignore` | 840 | 55438 | N/A | | `throughput \| null` | Error | 53617 | N/A | | `throughput \| rg 'x'` | 1165 | 3049 | 3736 | | `(throughput) \| rg 'x'` | 810 | 3085 | 3815 | (Numbers above are the median samples for throughput) This PR also paves the way to refactor our `ExternalStream` handling in the various commands. For example, this PR already fixes the following code: ```nushell ^sh -c 'echo -n "hello "; sleep 0; echo "world"' | find "hello world" ``` This returns an empty list on 0.90.1 and returns a highlighted "hello world" on this PR. Since the `stdout` and `stderr` `IoStream`s are available to commands when they are run, then this unlocks the potential for more convenient behavior. E.g., the `find` command can disable its ansi highlighting if it detects that the output `IoStream` is not the terminal. Knowing the output streams will also allow background job output to be redirected more easily and efficiently. # User-Facing Changes - External commands returned from closures will be collected (in most cases): ```nushell 1..2 | each {|_| nu -c "print a" } ``` This gives `["a", "a"]` on this PR, whereas this used to print "a\na\n" and then return an empty list. ```nushell 1..2 | each {|_| nu -c "print -e a" } ``` This gives `["", ""]` and prints "a\na\n" to stderr, whereas this used to return an empty list and print "a\na\n" to stderr. - Trailing new lines are always trimmed for external commands when piping into internal commands or collecting it as a value. (Failure to decode the output as utf-8 will keep the trailing newline for the last binary value.) In the current nushell version, the following three code snippets differ only in parenthesis placement, but they all also have different outputs: 1. `1..2 | each { ^echo a }` ``` a a ╭────────────╮ │ empty list │ ╰────────────╯ ``` 2. `1..2 | each { (^echo a) }` ``` ╭───┬───╮ │ 0 │ a │ │ 1 │ a │ ╰───┴───╯ ``` 3. `1..2 | (each { ^echo a })` ``` ╭───┬───╮ │ 0 │ a │ │ │ │ │ 1 │ a │ │ │ │ ╰───┴───╯ ``` But in this PR, the above snippets will all have the same output: ``` ╭───┬───╮ │ 0 │ a │ │ 1 │ a │ ╰───┴───╯ ``` - All existing flags on `run-external` are now deprecated. - File redirections now apply to all commands inside a code block: ```nushell (nu -c "print -e a"; nu -c "print -e b") e> test.out ``` This gives "a\nb\n" in `test.out` and prints nothing. The same result would happen when printing to stdout and using a `o>` file redirection. - External command output will (almost) never be ignored, and ignoring output must be explicit now: ```nushell (^echo a; ^echo b) ``` This prints "a\nb\n", whereas this used to print only "b\n". This only applies to external commands; values and internal commands not in return position will not print anything (e.g., `(echo a; echo b)` still only prints "b"). - `complete` now always captures stderr (`do` is not necessary). # After Submitting The language guide and other documentation will need to be updated. |
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Jakub Žádník
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e88a51e930
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Refactor scope commands (#10023)
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Stefan Holderbach
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62575c9a4f
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Document and critically review ShellError variants - Ep. 3 (#8340)
Continuation of #8229 and #8326 # Description The `ShellError` enum at the moment is kind of messy. Many variants are basic tuple structs where you always have to reference the implementation with its macro invocation to know which field serves which purpose. Furthermore we have both variants that are kind of redundant or either overly broad to be useful for the user to match on or overly specific with few uses. So I set out to start fixing the lacking documentation and naming to make it feasible to critically review the individual usages and fix those. Furthermore we can decide to join or split up variants that don't seem to be fit for purpose. # Call to action **Everyone:** Feel free to add review comments if you spot inconsistent use of `ShellError` variants. # User-Facing Changes (None now, end goal more explicit and consistent error messages) # Tests + Formatting (No additional tests needed so far) # Commits (so far) - Remove `ShellError::FeatureNotEnabled` - Name fields on `SE::ExternalNotSupported` - Name field on `SE::InvalidProbability` - Name fields on `SE::NushellFailed` variants - Remove unused `SE::NushellFailedSpannedHelp` - Name field on `SE::VariableNotFoundAtRuntime` - Name fields on `SE::EnvVarNotFoundAtRuntime` - Name fields on `SE::ModuleNotFoundAtRuntime` - Remove usused `ModuleOrOverlayNotFoundAtRuntime` - Name fields on `SE::OverlayNotFoundAtRuntime` - Name field on `SE::NotFound` |
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Jakub Žádník
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a3f817d71b
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Re-implement aliases (#8123)
# Description This PR adds an alternative alias implementation. Old aliases still work but you need to use `old-alias` instead of `alias`. Instead of replacing spans in the original code and re-parsing, which proved to be extremely error-prone and a constant source of panics, the new implementation creates a new command that references the old command. Consider the new alias defined as `alias ll = ls -l`. The parser creates a new command called `ll` and remembers that it is actually a `ls` command called with the `-l` flag. Then, when the parser sees the `ll` command, it will translate it to `ls -l` and passes to it any parameters that were passed to the call to `ll`. It works quite similar to how known externals defined with `extern` are implemented. The new alias implementation should work the same way as the old aliases, including exporting from modules, referencing both known and unknown externals. It seems to preserve custom completions and pipeline metadata. It is quite robust in most cases but there are some rough edges (see later). Fixes https://github.com/nushell/nushell/issues/7648, https://github.com/nushell/nushell/issues/8026, https://github.com/nushell/nushell/issues/7512, https://github.com/nushell/nushell/issues/5780, https://github.com/nushell/nushell/issues/7754 No effect: https://github.com/nushell/nushell/issues/8122 (we might revisit the completions code after this PR) Should use custom command instead: https://github.com/nushell/nushell/issues/6048 # User-Facing Changes Since aliases are now basically commands, it has some new implications: 1. `alias spam = "spam"` (requires command call) * **workaround**: use `alias spam = echo "spam"` 2. `def foo [] { 'foo' }; alias foo = ls -l` (foo defined more than once) * **workaround**: use different name (commands also have this limitation) 4. `alias ls = (ls | sort-by type name -i)` * **workaround**: Use custom command. _The common issue with this is that it is currently not easy to pass flags through custom commands and command referencing itself will lead to stack overflow. Both of these issues are meant to be addressed._ 5. TODO: Help messages, `which` command, `$nu.scope.aliases`, etc. * Should we treat the aliases as commands or should they be separated from regular commands? 6. Needs better error message and syntax highlight for recursed alias (`alias f = f`) 7. Can't create alias with the same name as existing command (`alias ls = ls -a`) * Might be possible to add support for it (not 100% sure) 8. Standalone `alias` doesn't list aliases anymore 9. Can't alias parser keywords (e.g., stuff like `alias ou = overlay use` won't work) * TODO: Needs a better error message when attempting to do so # Tests + Formatting Don't forget to add tests that cover your changes. Make sure you've run and fixed any issues with these commands: - `cargo fmt --all -- --check` to check standard code formatting (`cargo fmt --all` applies these changes) - `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect` to check that you're using the standard code style - `cargo test --workspace` to check that all tests pass # After Submitting If your PR had any user-facing changes, update [the documentation](https://github.com/nushell/nushell.github.io) after the PR is merged, if necessary. This will help us keep the docs up to date. |