The source-map flattening was throwing an error when there
is a cyclic dependency between source files and source-maps.
The error was either a custom one describing the cycle, or a
"Maximum call stack size exceeded" one.
Now this is handled more leniently, resulting in a partially loaded
source file (or source-map) and a warning logged.
Fixes#35727Fixes#35757
Fixes https://github.com/angular/angular-cli/issues/17106
Fixes https://github.com/angular/angular-cli/issues/17115
PR Close#36452
The library used by ngcc to update the source files (MagicString) is able
to generate a source-map but it is not able to account for any previous
source-map that the input text is already associated with.
There have been various attempts to fix this but none have been very
successful, since it is not a trivial problem to solve.
This commit contains a novel approach that is able to load up a tree of
source-files connected by source-maps and flatten them down into a single
source-map that maps directly from the final generated file to the original
sources referenced by the intermediate source-maps.
PR Close#35132
Pete Bacon Darwin