## 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
The new `dyn.Pattern` type represents a path pattern that can match one
or more paths in a configuration tree. Every `dyn.Path` can be converted
to a `dyn.Pattern` that matches only a single path.
To accommodate this change, the visit function needed to be modified to
take a `dyn.Pattern` suffix. Every component in the pattern implements
an interface to work with the visit function. This function can recurse
on the visit function for one or more elements of the value being
visited. For patterns derived from a `dyn.Path`, it will work as it did
before and select the matching element. For the new pattern components
(e.g. `dyn.AnyKey` or `dyn.AnyIndex`), it recurses on all the elements
in the container.
## Tests
Unit tests. Confirmed full coverage for the new code.
## Changes
The `dyn.Path` argument wasn't tested and could regress. Spotted this
while working on related code. Follow up to #1260.
## Tests
Unit tests.
## 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 function could panic when either side of the comparison is a nil or
empty slice. This logic is triggered when comparing the input value to
the output value when calling `dyn.Map`.
## Tests
Unit tests.
## Changes
This change adds the following functions:
* `dyn.Get(value, "foo.bar") -> (dyn.Value, error)`
* `dyn.Set(value, "foo.bar", newValue) -> (dyn.Value, error)`
* `dyn.Map(value, "foo.bar", func) -> (dyn.Value, error)`
And equivalent functions that take a previously constructed `dyn.Path`:
* `dyn.GetByPath(value, dyn.Path) -> (dyn.Value, error)`
* `dyn.SetByPath(value, dyn.Path, newValue) -> (dyn.Value, error)`
* `dyn.MapByPath(value, dyn.Path, func) -> (dyn.Value, error)`
Changes made by the "set" and "map" functions are never reflected in the
input argument; they return new `dyn.Value` instances for all nodes in
the path leading up to the changed value.
## Tests
New unit tests cover all critical paths.
Pieter Noordhuis