## Changes
Add `merge.Override` transform. It allows the override one `dyn.Value`
with another, preserving source locations for parts of the sub-tree
where nothing has changed. This is different from merging, where values
are concatenated.
`OverrideVisitor` is visiting the changes during the override process
and allows to control of what changes are allowed or update the
effective value.
The primary use case is Python code updating bundle configuration.
During override, we update locations only for changed values. This
allows us to keep track of locations where values were initially defined
and used for error reporting. For instance, merging:
```yaml
resources: # location=left.yaml:0
jobs: # location=left.yaml:1
job_0: # location=left.yaml:2
name: "job_0" # location=left.yaml:3
```
with
```yaml
resources: # location=right.yaml:0
jobs: # location=right.yaml:1
job_0: # location=right.yaml:2
name: "job_0" # location=right.yaml:3
description: job 0 # location=right.yaml:4
job_1: # location=right.yaml:5
name: "job_1" # location=right.yaml:5
```
produces
```yaml
resources: # location=left.yaml:0
jobs: # location=left.yaml:1
job_0: # location=left.yaml:2
name: "job_0" # location=left.yaml:3
description: job 0 # location=right.yaml:4
job_1: # location=right.yaml:5
name: "job_1" # location=right.yaml:5
```
## Tests
Unit tests
## Changes
Before this change maps were stored as a regular Go map with string
keys. This didn't let us capture metadata (location information) for map
keys.
To address this, this change replaces the use of the regular Go map with
a dedicated type for a dynamic map. This type stores the `dyn.Value` for
both the key and the value. It uses a map to still allow O(1) lookups
and redirects those into a slice.
## Tests
* All existing unit tests pass (some with minor modifications due to
interface change).
* Equality assertions with `assert.Equal` no longer worked because the
new `dyn.Mapping` persists the order in which keys are set and is
therefore susceptible to map ordering issues. To fix this, I added a
`dynassert` package that forwards all assertions to `testify/assert` but
intercepts equality for `dyn.Value` arguments.
## Changes
This change means the callback supplied to `dyn.Foreach` can introspect
the path of the value it is being called for. It also prepares for
allowing visiting path patterns where the exact path is not known
upfront.
## Tests
Unit tests.
## Changes
This is a fundamental change to how we load and process bundle
configuration. We now depend on the configuration being represented as a
`dyn.Value`. This representation is functionally equivalent to Go's
`any` (it is variadic) and allows us to capture metadata associated with
a value, such as where it was defined (e.g. file, line, and column). It
also allows us to represent Go's zero values properly (e.g. empty
string, integer equal to 0, or boolean false).
Using this representation allows us to let the configuration model
deviate from the typed structure we have been relying on so far
(`config.Root`). We need to deviate from these types when using
variables for fields that are not a string themselves. For example,
using `${var.num_workers}` for an integer `workers` field was impossible
until now (though not implemented in this change).
The loader for a `dyn.Value` includes functionality to capture any and
all type mismatches between the user-defined configuration and the
expected types. These mismatches can be surfaced as validation errors in
future PRs.
Given that many mutators expect the typed struct to be the source of
truth, this change converts between the dynamic representation and the
typed representation on mutator entry and exit. Existing mutators can
continue to modify the typed representation and these modifications are
reflected in the dynamic representation (see `MarkMutatorEntry` and
`MarkMutatorExit` in `bundle/config/root.go`).
Required changes included in this change:
* The existing interpolation package is removed in favor of
`libs/dyn/dynvar`.
* Functionality to merge job clusters, job tasks, and pipeline clusters
are now all broken out into their own mutators.
To be implemented later:
* Allow variable references for non-string types.
* Surface diagnostics about the configuration provided by the user in
the validation output.
* Some mutators use a resource's configuration file path to resolve
related relative paths. These depend on `bundle/config/paths.Path` being
set and populated through `ConfigureConfigFilePath`. Instead, they
should interact with the dynamically typed configuration directly. Doing
this also unlocks being able to differentiate different base paths used
within a job (e.g. a task override with a relative path defined in a
directory other than the base job).
## Tests
* Existing unit tests pass (some have been modified to accommodate)
* Integration tests pass
## Changes
The name "dynamic value", or "dyn" for short, is more descriptive than
the opaque "config". Also, it conveniently does not alias with other
packages in the repository, or (popular ones) elsewhere.
(discussed with @andrewnester)
## Tests
n/a
Gleb Kanterov
Pieter Noordhuis