## Changes
Test failures indicate that both stdout and stderr are consumed, yet the
content of stdout doesn't end up in the intended output. This can happen
if the goroutines responsible for writing to the combined output buffer
attempt to write to the same underlying buffer concurrently.
Example failure:
```
=== RUN TestBackgroundCombinedOutput
background_test.go:65:
Error Trace: D:/a/cli/cli/libs/process/background_test.go:65
Error: elements differ
extra elements in list A:
([]interface {}) (len=1) {
(string) (len=1) "2"
}
listA:
([]string) (len=2) {
(string) (len=1) "1",
(string) (len=1) "2"
}
listB:
([]string) (len=1) {
(string) (len=1) "1"
}
Test: TestBackgroundCombinedOutput
```
With the test body:
ca45e53f42/libs/process/background_test.go (L48-L66)
With the implementation of `WithCombinedOutput`:
ca45e53f42/libs/process/opts.go (L72-L78)
Notice that `c.Stdout` does get the "2", or the test failure would have
included the relevant assertion error. This leads me to believe that
there is a race on writing to `buf` from the two goroutines writing to
`c.Stdout` and `c.Stderr`.
## Tests
The test passes. If this PR has the intended effect remains to be
seen...
## Changes
Add ApplyPythonMutator, which will fork the Python subprocess and
process pipe bundle configuration through it.
It's enabled through `experimental` section, for example:
```yaml
experimental:
pydabs:
enable: true
venv_path: .venv
```
For now, it's limited to two phases in the mutator pipeline:
- `load`: adds new jobs
- `init`: adds new jobs, or modifies existing ones
It's enforced that no jobs are modified in `load` and not jobs are
deleted in `load/init`, because, otherwise, it will break existing
assumptions.
## Tests
Unit tests
## Changes
The order of stdout and stderr being read into the buffer for combined
output is not deterministic due to scheduling of the underlying
goroutines that consume them. That's why this asserts on the contents
and not the order.
## Changes
This PR adds higher-level wrappers for calling subprocesses. One of the
steps to get https://github.com/databricks/cli/pull/637 in, as
previously discussed.
The reason to add `process.Forwarded()` is to proxy Python's `input()`
calls from a child process seamlessly. Another use-case is plugging in
`less` as a pager for the list results.
## Tests
`make test`
Pieter Noordhuis
Gleb Kanterov
Serge Smertin
Andrew Nester