Currently we always prompt when the static-query migration runs. This is not
always needed because some applications do not even use `ViewChild` or
`ContentChild` queries and it just causes confusion if developers need to
decide on a migration strategy while there is nothing to migrate.
In order to avoid this confusion, we no longer prompt for a strategy
if there are no queries declared within the project.
PR Close#30254
Currently if there are multiple source files within a given
TypeScript source file, only the last template in the source
file is checked as we store templates in a `Map` with the
source file paths as keys.
This is problematic as multiple templates can live within the
same source file and we therefore accidentally overwrite
existing entries in the resolved templates map.
PR Close#29841
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
Introduces a new update schematic called "template-var-assignment"
that is responsible for analyzing template files in order to warn
developers if template variables are assigned to values.
The schematic also comes with a driver for `tslint` so that the
check can be used wtihin Google.
PR Close#29608
Paul Gschwendtner