Ngcc adds properties to the `package.json` files of the entry-points it
processes to mark them as processed for a format and point to the
created Ivy entry-points (in case of `--create-ivy-entry-points`). When
running ngcc in parallel mode (which is the default for the standalone
ngcc command), multiple formats can be processed simultaneously for the
same entry-point and the order of completion is not deterministic.
Previously, ngcc would append new properties at the end of the target
object in `package.json` as soon as the format processing was completed.
As a result, the order of properties in the resulting `package.json`
(when processing multiple formats for an entry-point in parallel) was
not deterministic. For tools that use file hashes for caching purposes
(such as Bazel), this lead to a high probability of cache misses.
This commit fixes the problem by ensuring that the position of
properties added to `package.json` files is deterministic and
independent of the order in which each format is processed.
Jira issue: [FW-1801](https://angular-team.atlassian.net/browse/FW-1801)
Fixes#34635
PR Close#34870
To persist some of its state, `ngcc` needs to update `package.json`
files (both in memory and on disk).
This refactoring abstracts these operations behind the
`PackageJsonUpdater` interface, making it easier to orchestrate them
from different contexts (e.g. when running tasks in parallel on multiple
processes).
Inspired by/Based on @alxhub's prototype: alxhub/angular@cb631bdb1
PR Close#32427
Pete Bacon Darwin
George Kalpakas