Skip to:

  1. Skip to Jira Navigation
  2. Skip to Side Navigation
  3. Skip to Main Content

Libs are blindly added into loaded-libs even if an error occurs during loading

Description

Suppose you have a lib that causes some errors during loading, like the following:

And then, if you require the lib, it would be added into loaded-libs in spite of the reader error, which makes require succeed silently after that.

Things get worse if you have another namespace that requires a broken lib (say here broken-lib.core):

Although you'll get the actual error the first time you load the depending namespace, after that you'll find a wrong compiler exception thrown every time you try to reload it. The situation will last even after you actually do fix the code causing the original error.

Cause:
The patch for CLJ-1116 made the ns macro blindly add the lib being defined into loaded-libs even if an error occurs during loading.

Approach:
Modify clojure.core/load-lib so that it removes the lib from loaded-libs on error.

Environment

None

Attachments

2

Activity

Show:

Alex Miller June 26, 2018 at 5:52 PM

Note - CLJ-2026 may be made irrelevant by any fix to this broader problem and could then be pulled out.

Ghadi Shayban March 18, 2018 at 8:05 PM

Attached a similar approach as Shogo Ohta's original. Given the way ns now works, I see this approach as tenable.

To support dynamic ns creation at the REPL, CLJ-1116 wrote to loaded-libs inside the ns macro, and at the same time made some logic in load-lib and load-libs unnecessary. This set of patches undoes the side-effect when loading fails, and cleans up some dead conditionals.

New behavior: Given ns A which requires #{B, C}, if B loads but C doesn't, only B will be written to loaded-libs, and A and C will be undone. This improves the experience with load and fixes all of the annoying behavior in the ticket description.

NB: the 'require' patch entails:
If a lib is specified in an ns :require or :use, loading that lib the first time must result in an ns that corresponds exactly to the lib name. (There is not and has never been this restriction when calling `load` directly, but only via `ns`) I was surprised to find in the test suite an accidental lib with underscores where the loaded code results in a namespace with a dash. (Perhaps c.c.specs should specify a tighter spec for libs than 'simple-symbol?')

The commits are separated, with accompanying short explanatory comments.

Shogo Ohta October 15, 2016 at 7:34 AM

What kind of solution are you expecting for this problem?

To prevent the lib from being added to loaded-libs in the first place, I think ns macro needs to know where it is used from. It should immediately add the ns when used in the REPL for CLJ-1116, while it should defer adding the ns until completing loading whole the file without errors when used within a file.

Alex Miller September 22, 2016 at 7:41 PM

I don't think this solution is good as is so moving to Incomplete.

Shogo Ohta April 17, 2014 at 3:21 PM

To do so, I think we need to revert CLJ-1116.

Details

Assignee

Reporter

Approval

Vetted

Patch

Code

Priority

Affects versions

Created April 17, 2014 at 3:00 PM
Updated October 2, 2019 at 2:27 PM