If target has no outputs set, and no global outputGlob set, assume no outputs

[dobesv]

Assuming that every file in the target directory is an output to be cached doesn't seem correct here - if they didn't specify outputs, assume there are none instead.

[ecraig12345]

Thanks for the contribution, but this seems like a risky change since outputs and outputGlob are both optional, and there's no config validation error if neither is defined. So it's changing from implicitly caching (probably) too much to implicitly caching nothing--neither behavior is great, but at least outside a major bump I think it's safer to preserve what's done today.

[dobesv]

The current behavior seems broken to me. But it's up to you I guess. I have a workaround in place.

Or are you saying I should update the pull request to do a major version bump?

[dobesv]

The current behavior seems broken to me. But it's up to you I guess. I have a workaround in place.

Or are you saying I should update the pull request to do a major version bump?

[ecraig12345]

The current behavior seems broken to me. But it's up to you I guess. I have a workaround in place.

Or are you saying I should update the pull request to do a major version bump?

I agree it's weird, but it's too significant of a change in default behavior outside a major version bump. It's also unfortunate that the doc comments inherited from backfill say the default is lib/**/*, but that doesn't appear to be true with the way lage sets up the config, and isn't a good assumption anyway since not everyone uses that output structure.

Probably the "right" approach in the next major version is to make cacheOptions.outputGlob and probably .environmentGlob required, since the behavior without either of those options is pretty bad/unexpected and defeats a significant part of the purpose of using lage. Lage is widely used enough that we don't want to bump the major version for just one change, but we probably will need a major bump due to Node version requirements in the near-ish future, so maybe this could be done at that time.

[dobesv]

One thought that comes to mind is maybe add some kind of config checking command like "lage lint-config" which you could start recommending people add to their CI flow.  It could have stricter rules, like requiring these fields you mentioned.  But it wouldn't break backwards compatibility because it wouldn't cause an error when running lage build. Or perhaps you could put a version into the lage config object or a new option that sets the default for outputs as other thoughts for backcompat while addressing this footgun. Just some thoughts... You can also just put it off

…

On Jan 27, 2026 at 1:53 AM -0800, Elizabeth Craig ***@***.***>, wrote: ecraig12345 left a comment (microsoft/lage#878) > The current behavior seems broken to me. But it's up to you I guess. I have a workaround in place. > Or are you saying I should update the pull request to do a major version bump? I agree it's weird, but it's too significant of a change in default behavior outside a major version bump. It's also unfortunate that the doc comments inherited from backfill say the default is lib/**/*, but that doesn't appear to be true with the way lage sets up the config, and isn't a good assumption anyway since not everyone uses that output structure. Probably the "right" approach in the next major version is to make cacheOptions.outputGlob and probably .environmentGlob required, since the behavior without either of those options is pretty bad/unexpected and defeats a significant part of the purpose of using lage. Lage is widely used enough that we don't want to bump the major version for just one change, but we probably will need a major bump due to Node version requirements in the near-ish future, so maybe this could be done at that time. — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.Message ID: ***@***.***>

[ecraig12345]

So...upon further investigation, I think having no default for outputGlob was an accident due to this last line:

lage/packages/scheduler/src/cache/createCacheProvider.ts

Lines 29 to 33 in 4e436f2

	: new BackfillCacheProvider({
	logger,
	root,
	cacheOptions: {
	outputGlob: cacheOptions?.outputGlob,

Which results in outputGlob: undefined, which overwrites the default from backfill... 🤦‍♀️

lage/packages/cache/src/backfillWrapper.ts

Lines 37 to 41 in 4e436f2

	const mergedConfig = {
	...createDefaultConfig(cwd),
	...cacheOptions,
	...envConfig,
	} as Config;

And the types in this area as well as several others are a mess, with inaccurate indication of what's actually required or might be undefined...

I guess since the behavior with no outputGlob is kind of nonsense, and all nontrivial usage of lage should have outputGlob overridden already, I'm now leaning towards going ahead and changing something--probably fixing the inheritance of the documented lib/**/* default from backfill, then changing the option to properly be required in a future major version (#987).