Config specific imports don't work with analyzer/ddc

[jakemac53]

I have been working on a prototype to support config specific imports properly in package:build, and I have gotten something to work, but during compilation I get errors like this:

Error compiling dartdevc module:_test|web/main.ddc.js

[error] Target of URI doesn't exist: 'default.dart'. (/web/main.dart, line 7, col 8)
[error] Target of URI doesn't exist: 'ui.dart'. (/web/main.dart, line 8, col 26)
[error] Target of URI doesn't exist: 'io.dart'. (/web/main.dart, line 9, col 26)

Please fix all errors before compiling (warnings are okay).

my imports look like this:

import 'default.dart'
    if (dart.library.ui) 'ui.dart'
    if (dart.library.io) 'io.dart'
    if (dart.library.html) 'web.dart';

Note that you don't see the error about web.dart, because I did in fact provide that one (because I knew it was the only one that would actually be loaded).

I can work around the issue with // ignore: URI_DOES_NOT_EXIST comments (although I need one for every single condition...), but that shouldn't be necessary :).

It looks like this error is probably coming from the analyzer, but I am unsure if I should assign it to the dev_compiler or analyzer areas - assigning to analyzer for now but please switch if you feel that is incorrect.

[jakemac53]

cc @vsmenon @jmesserly

[jakemac53]

I am marking this as p1 because supporting config specific imports is on my Q3 okrs, and this is effectively a blocker for that I think, but we could re-adjust if we think requiring the // ignore is acceptable.

[vsmenon]

Assigning to @jmesserly to triage. If we're moving to DDK, we might be able to avoid this. @jakemac53 - do you know if we have a similar issue with kernel?

OTOH, it's possible analyzer build mode will hit the analogous issue.

[jakemac53]

analyzer build mode does not appear to have this issue (when creating summaries) - but I don't know that they report errors at all.

[jakemac53]

I will also check with Kernel/DDK next week, if it does work we can probably not worry about fixing this.

[jakemac53]

The ddk pipeline is a bit broken right now (going to look into a fix in the SDK soon), but I was able to hack some stuff together and it looks like this is still an issue. I end up getting this error:

org-dartlang-app:/web/io.dart:1: Error: StandardFileSystem only supports file:* and data:* URIs

It shouldn't be trying to read that file at all, I think the multiroot file system falls back on the standard one if it can't actually find a file which is why you see this specific error.

[jmesserly]

yeah I had removed multi-root temporarily to eliminate variables. I'm trying to merge dartdevk into dartdevc (we need to only have one compiler binary), this requires making them support the same command line options.

To that end I removed options that were added to dartdevk, but unsupported by dartdevc. The theory is, nobody is using dartdevk yet (it was just our testing ground for kernel/CFE support), so options can be removed to simplify the merge. I agree that we need something like mutli-root long term (it is much nicer than existing dartdevc/dart2js/dartanalyzer support for build systems, which has undocumented options that differ between each compiler). I may be able to port it to dartdevc but I'm not sure. Analyzer's APIs for URI resolution and resource providers is pretty different from CFE's support. So we may need to wait for DDC to switch fully to CFE/Kernel.

Anyways, that's the story behind those options. :)

[jmesserly]

I think this is an Analyzer issue; I believe we have one tracking it, let me see if I can find it.

[jmesserly]

I think this is the same issue as #34179 ... LMK if I'm wrong about that, we can reopen this.