Currently there are two available migration strategies for the `static-query`
schematic. Both have benefits and negatives which depend on what the
developer prefers. Since we can't decide which migration strategy is the
best for a given project, the developer should be able to select a specific
strategy through a simple choice prompt.
In order to be able to use prompts in a migration schematic, we need to
take advantage of the "inquirer" package which is also used by the CLI
schematic prompts (schematic prompts are usually only statically defined
in the schema). Additionally the schematic needs to be made "async"
because with prompts the schematic can no longer execute synchronously
without implementing some logic that blocks the execution.
PR Close#29876
Introduces a new strategy for the `static-query` schematic that
is enabled by default. In order to provide a migration that works
for the most Angular applications and makes the upgrade as easy
as possible, the template strategy leverages the view engine
Angular compiler logic in order to determine the query timing
that is currently used within applications using view engine.
PR Close#29815
In order to support multiple strategies for detecting the query timing, the
query usage logic has been moved into a query usage strategy.
PR Close#29815
Queries can technically be also accessed within component templates
e.g.
```html
<my-comp [binding]="myQuery"></my-comp>
```
In that case the query with the property "myQuery" is accessed
statically and needs to be marked with `static: true`. There are
other edge cases that need to be handled as the template property
read doesn't necessarily resolve to the actual query property.
For example:
```html
<foo #myQuery></foo>
<my-comp [binding]="myQuery"></my-comp>
```
In this scenario the binding doesn't refer to the actual query
because the template reference variable takes precedence. The
query doesn't need to be marked with "static: true" this time.
This commit ensures that the `static-query` migration schematic
now handles this cases properly. Also template property reads
that access queries from within a `<ng-template>` are ignored
as these can't access the query before the view has been initialized.
Resolves FW-1216
PR Close#29713
In order to be able to use the static-query migration logic within
Google, we need to provide a TSLint rule entry-point that wires up
the schematic logic and provides reporting and automatic fixes.
PR Close#29258
Introduces an update schematic for the "@angular/core" package
that automatically migrates pre-V8 "ViewChild" and "ContentChild"
queries to the new explicit timing syntax. This is not required
yet, but with Ivy, queries will be "dynamic" by default. Therefore
specifying an explicit query timing ensures that developers can
smoothly migrate to Ivy (once it's the default).
Read more about the explicit timing API here:
https://github.com/angular/angular/pull/28810
PR Close#28983
Paul Gschwendtner