Add back support to reinstall linked dependencies on change

[FredKSchott]

Original Discussion: #429
/cc @joaotavora

Regression:

commit 610fb9d28452bf24758387a00fe81a4ed103e503
diff --git a/packages/snowpack/src/commands/dev.ts b/packages/snowpack/src/commands/dev.ts
--- a/packages/snowpack/src/commands/dev.ts
+++ b/packages/snowpack/src/commands/dev.ts
@@ -954,3 +880,3 @@
   function onDepWatchEvent() {
-    reinstallDependencies().then(() => hmrEngine.broadcastMessage({type: 'reload'}));
+    hmrEngine.broadcastMessage({type: 'reload'});
   }

[joaotavora]

I'm working on a fix right now :-) Having fun, but I won't be suprised if you beat me to it, since they'll be my first ever lines of OSS javascript/typescript.

[FredKSchott]

Nice! Let me know how I can help. That commit should include the old implementation of reinstallDependencies(), which may need to change a bit since it's so old now, but should have enough to point you in the right direction. Appreciate the help!

[joaotavora]

I'm making progress, indeed. I'll let you know if I am blocked. First I'll try to get back that function you mention and get this working the way it presumably used to.

After that is done, I was thinking of being a little more ambitious and installing only the dependency that we know has changed, since I think reinstallDependencies installs all of them. In theory it should be possible to know which one we need to update by correlating the argument to onDepWatchEvent which is the file/directory that changed with some other global structure.

[joaotavora]

After much rummaging around in the code, I've settled for exporting and re-using an function in sources/local instead of bringing back the defunct reinstallDependencies(). I thus touch very few lines, which is always a good idea in my book. Maybe/probably this misses some important detail but it works. Getting late now, going to bed.

[joaotavora]

@FredKSchott what's the status on this? Do you think the fix I'm proposing will get merged in the near future, or do you have something else in mind? I think something more elaborate and/or efficient is clearly possible, but at least merging my fix seems to bring back the previous behavior.

[FredKSchott]

Sorry for the delay on this, I've been on holiday and then immediately went heads down into getting v3.0 out the door. Should have more time to take a look at this in the next couple of days. I can also help you rebase your PR, given that a few things had to move around for v3.0 since you started on it.

[joaotavora]

I can also help you rebase your PR, given that a few things had to move around for v3.0 since you started on it.

I think I just did that, rebase on top of main with a few changes (I think the stuff you moved around makes things slightly clearer).

It's working fine, as far as I can tell, though on upgrading Snowpack to main I had to npm i --legacy-peer-deps because of some dependency breakage that I didn't understand. It doesn't seem to affect anything, though

[joaotavora]

By the way, I found and fixed another bug. When making the FS watcher for linked deps, better consider config.exclude (which is node_modules and stuff), otherwise it's really easy to blow past the default limit for FS-watching handles. Put it in the same PR: a0f4b17

[gaberogan]

Is there currently a workaround for this?
edit: this appears to work
npx snowpack dev --reload

[andrew-c-tran]

Any word on this? it appears to have been ready for quite some time now

[joaotavora]

According to #2091 (comment), this is supposed to be fixed now (with another change, not my PR).

I wouldn't know, I haven't used Snowpack for some time :-/.

But maybe this can be closed?

[donmccurdy]

I'm finding that not only are changes in linked dependencies not detected, but Snowpack can't build (at all) with any linked dependencies involved. Have tried clearing the cache and using --reload. Continue to get errors like:

 Error: Unexpected: Unscanned package import "<my-package>" couldn't be built/resolved.

This one is pretty important to my development workflow, anything we can do to help?

[RodrigoHamuy]

Any updates on this? I also can't use linked packages on latest Snowpack.

[joaotavora]

See my comment #2088 (comment). It's supposed to be fixed !

[RodrigoHamuy]

Thanks @joaotavora . I am using snowpack version 3.8.2 and the issue is still present so I don't think is fixed yet.