Avoid crashing when installing from a corrupted lockfile

[composerinteralia]

What was the end-user or developer problem that led to this PR?

I did a bad thing (script that edits the Gemfile.lock directly) and ended up with a Gemfile.lock that was completely missing some indirect dependencies. While this is my fault and an error is reasonable, I noticed that the error got progressively less friendly in recent versions of bundler.

Something similar came up in #6210, and this commit would have helped with that case as well (although we've already handled that a different way with #6219).

Previous behavior

Back on Bundler 2.2.23, a corrupt lockfile like this would cause a helpful error:

Unable to find a spec satisfying minitest (>= 5.1) in the set. Perhaps the lockfile is corrupted?

Bundler 2.2.24 to 2.3.26 gave a helpful (if inaccurate, since an old Bundler was not necessarily at fault) warning:

Warning:
Your lockfile was created by an old Bundler that left some things out.
Because of the missing DEPENDENCIES, we can only install gems one at a time,
instead of installing 16 at a time.
You can fix this by adding the missing gems to your Gemfile, running bundle
install, and then removing the gems from your Gemfile.
The missing gems are:
* minitest depended upon by activesupport

But then continued on and crashed while trying to report the unmet dependency:

--- ERROR REPORT TEMPLATE -------------------------------------------------------

NoMethodError: undefined method `full_name' for nil:NilClass
lib/bundler/installer/parallel_installer.rb:127:in `block (2 levels) in check_for_unmet_dependencies'

...

Bundler 2.4.0 and up crash as above when jobs=1, but crash even harder when run in parallel:

--- ERROR REPORT TEMPLATE -------------------------------------------------------

fatal: No live threads left. Deadlock?
3 threads, 3 sleeps current:0x00007fa6b6704660 main thread:0x00007fa6b6704660
* #<Thread:0x000000010833b130 sleep_forever>
   rb_thread_t:0x00007fa6b6704660 native:0x0000000108985600 int:0

* #<Thread:0x0000000108dea630@Parallel Installer Worker #0 tmp/1/gems/system/gems/bundler-2.5.0.dev/lib/bundler/worker.rb:90 sleep_forever>
   rb_thread_t:0x00007fa6b67f67c0 native:0x0000700009a62000 int:0

* #<Thread:0x0000000108dea4a0@Parallel Installer Worker #1 tmp/1/gems/system/gems/bundler-2.5.0.dev/lib/bundler/worker.rb:90 sleep_forever>
   rb_thread_t:0x00007fa6b67f63c0 native:0x0000700009c65000 int:0

<internal:thread_sync>:18:in `pop'
tmp/1/gems/system/gems/bundler-2.5.0.dev/lib/bundler/worker.rb:42:in `deq'

...

Note that these crashes only happen when installing local. When installing from a remote we end up getting an APIResponseMismatchError via

rubygems/bundler/lib/bundler/remote_specification.rb

Line 55 in 2f48d60

SharedHelpers.ensure_same_dependencies(self, dependencies, spec.dependencies)

What is your fix for the problem, implemented in this PR?

This commit fixes the confusing thread deadlock crash by detecting if dependencies are missing such that we'll never be able to enqueue. When that happens we treat it as a failure so the install can finish.

That gets us back to the NoMethodError, which this commit fixes by using a different warning in the case where no spec is found.

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags

[deivid-rodriguez]

Thank you, looking good. Normally I try to automatically re-resolve and fix the lockfile if we detect it's corrupted. But it's tricky sometimes, so changing a bad error message with a good error message is great!

[composerinteralia]

Thank you, looking good. Normally I try to automatically re-resolve and fix the lockfile if we detect it's corrupted. But it's tricky sometimes, so changing a bad error message with a good error message is great!

Played around with that a bit and it does seems possible. I can do that in a couple weeks when I get back from a vacation.

[deivid-rodriguez]

That'd be awesome! For now enjoy your vacation ❤️

[deivid-rodriguez]

I'm merging this for now regardless since this seems like a strict improvement!