fix(ngcc): update package.json deterministically (#34870)

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

packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts

@@ -760,6 +760,79 @@ runInEachFileSystem(() => {
         expect(pkg.fesm5_ivy_ngcc).toEqual('__ivy_ngcc__/fesm5/core.js');
         expect(pkg.module_ivy_ngcc).toEqual('__ivy_ngcc__/fesm5/core.js');
       });
+
+      it('should update `package.json` deterministically (regardless of entry-point processing order)',
+         () => {
+           // Ensure formats are not marked as processed in `package.json` at the beginning.
+           let pkg = loadPackage('@angular/core');
+           expectNotToHaveProp(pkg, 'esm5_ivy_ngcc');
+           expectNotToHaveProp(pkg, 'fesm2015_ivy_ngcc');
+           expectNotToHaveProp(pkg, 'fesm5_ivy_ngcc');
+           expectNotToHaveProp(pkg, '__processed_by_ivy_ngcc__');
+
+           // Process `fesm2015` and update `package.json`.
+           pkg = processFormatAndUpdatePackageJson('fesm2015');
+           expectNotToHaveProp(pkg, 'esm5_ivy_ngcc');
+           expectToHaveProp(pkg, 'fesm2015_ivy_ngcc');
+           expectNotToHaveProp(pkg, 'fesm5_ivy_ngcc');
+           expectToHaveProp(pkg.__processed_by_ivy_ngcc__ !, 'fesm2015');
+
+           // Process `fesm5` and update `package.json`.
+           pkg = processFormatAndUpdatePackageJson('fesm5');
+           expectNotToHaveProp(pkg, 'esm5_ivy_ngcc');
+           expectToHaveProp(pkg, 'fesm2015_ivy_ngcc');
+           expectToHaveProp(pkg, 'fesm5_ivy_ngcc');
+           expectToHaveProp(pkg.__processed_by_ivy_ngcc__ !, 'fesm5');
+
+           // Process `esm5` and update `package.json`.
+           pkg = processFormatAndUpdatePackageJson('esm5');
+           expectToHaveProp(pkg, 'esm5_ivy_ngcc');
+           expectToHaveProp(pkg, 'fesm2015_ivy_ngcc');
+           expectToHaveProp(pkg, 'fesm5_ivy_ngcc');
+           expectToHaveProp(pkg.__processed_by_ivy_ngcc__ !, 'esm5');
+
+           // Ensure the properties are in deterministic order (regardless of processing order).
+           const pkgKeys = stringifyKeys(pkg);
+           expect(pkgKeys).toContain('|esm5_ivy_ngcc|esm5|');
+           expect(pkgKeys).toContain('|fesm2015_ivy_ngcc|fesm2015|');
+           expect(pkgKeys).toContain('|fesm5_ivy_ngcc|fesm5|');
+
+           // NOTE:
+           // Along with the first format that is processed, the typings are processed as well.
+           // Also, once a property has been processed, alias properties as also marked as
+           // processed. Aliases properties are properties that point to the same entry-point file.
+           // For example:
+           // - `fesm2015` <=> `es2015`
+           // - `fesm5` <=> `module`
+           expect(stringifyKeys(pkg.__processed_by_ivy_ngcc__ !))
+               .toBe('|es2015|esm5|fesm2015|fesm5|module|typings|');
+
+           // Helpers
+           function expectNotToHaveProp(obj: object, prop: string) {
+             expect(obj.hasOwnProperty(prop))
+                 .toBe(
+                     false,
+                     `Expected object not to have property '${prop}': ${JSON.stringify(obj, null, 2)}`);
+           }
+
+           function expectToHaveProp(obj: object, prop: string) {
+             expect(obj.hasOwnProperty(prop))
+                 .toBe(
+                     true,
+                     `Expected object to have property '${prop}': ${JSON.stringify(obj, null, 2)}`);
+           }
+
+           function processFormatAndUpdatePackageJson(formatProp: string) {
+             mainNgcc({
+               basePath: '/node_modules/@angular/core',
+               createNewEntryPointFormats: true,
+               propertiesToConsider: [formatProp],
+             });
+             return loadPackage('@angular/core');
+           }
+
+           function stringifyKeys(obj: object) { return `|${Object.keys(obj).join('|')}|`; }
+         });
     });
 
     describe('diagnostics', () => {