Crystal Nightly Build Failure: Troubleshooting And Fix

Hey everyone,

We've got a bit of a situation on our hands with the nightly builds of crystal. It seems like things are a little wonky, and I wanted to break down exactly what's happening, why it's happening, and what we're doing to fix it. Let's dive in!

The Issue: Nightly Builds Failing

So, here's the scoop: the nightly builds of crystal are currently failing. If you're wondering where to see this in action, you can check out this link to the CircleCI pipeline. This is where we track our builds, and right now, it's showing some red flags. The core problem seems to stem from a make dependency issue that's related to file modification times. Essentially, the make install command is mistakenly identifying the compiler binary as outdated and triggering a rebuild.

Diving Deeper into the make Dependency Issue

To really understand what’s going on, we need to get into the nitty-gritty of how make works. make is a build automation tool that relies on timestamps to determine whether a target needs to be rebuilt. It compares the modification times of the source files with the modification time of the resulting binary. If the source files are newer, make rebuilds the binary. Now, here's where things get tricky. For some reason, in these nightly builds, the make install command is incorrectly thinking that the compiler binary is older than it should be, even if it isn't. This triggers an unnecessary rebuild. This rebuild is the root cause of our problems, because it misses a crucial setting needed to produce a static binary. A static binary is self-contained, meaning it includes all its dependencies within the executable file itself. This is super important for ensuring that our compiled programs can run on different systems without needing specific libraries installed.

The Rebuild and the Missing Static Linking

When make rebuilds the compiler, it's not including the setting that tells it to create a static binary. The result? We end up with a dynamically linked executable. This means the executable relies on external libraries to be present on the system where it's running. If those libraries aren't there, the program won't run. This is a big issue because it breaks the portability that we aim for with crystal. This situation is eerily similar to a previous issue, #330, which affected shards. It's like we're seeing a repeat performance, but this time with the core crystal compiler itself. It's crucial to nail down why this keeps happening so we can prevent it in the future.

The Timeline: When Did This Start?

This issue reared its head in yesterday's nightly build. That’s our starting point for figuring out the root cause. Pinpointing the exact change that triggered this behavior is key to resolving it. We're digging through the logs and changes from that period to see what might be causing the misidentification of file modification times. It's like detective work, but for compilers!

The Temporary Fix: Touching Files?

From initial investigations, it seems like we might need to “touch” some files during the build process. Touching a file essentially updates its modification timestamp without changing its content. This might trick make into thinking the binary is up-to-date and prevent the unnecessary rebuild. However, this is just a potential workaround, not a long-term solution. We need to understand the underlying cause to implement a proper fix. It's like putting a band-aid on a cut – it helps for now, but we need to stitch it up properly.

Why the Build Job Doesn't Fail Immediately

Here’s a tricky part: the main build job itself isn't failing right away. We have a check in place to verify static linking, which should catch this issue. However, this check runs before the problematic make install command rebuilds the compiler without static linking. So, the initial check passes, but the subsequent rebuild introduces the dynamic linking issue. It’s like a sneaky bug that’s hiding in the shadows!

The Jobs That Are Failing

The jobs that are actually failing are dist_docs and test_dist_linux_on_docker. These jobs try to execute the compiler in a Linux environment where the dynamic loader isn't set up to handle dynamically linked executables. In other words, these jobs are the canaries in the coal mine, alerting us to the fact that the compiler is dynamically linked when it shouldn't be. The error messages they produce are a clear signal that something is amiss. It's like hearing a smoke alarm – you know something's not right, even if you don't see the fire yet.

The Investigation and the Path Forward

So, what's next? We're actively investigating the root cause of this issue. Here’s a breakdown of the steps we’re taking:

1. Analyzing Recent Changes: We're meticulously reviewing the changes that went into yesterday's nightly build to identify any potential triggers for this behavior. This involves comparing the codebase before and after the problematic build to see what might have affected the make process. It's like sifting through clues to find the smoking gun.
2. Reproducing the Issue Locally: We're trying to reproduce the issue in a local development environment. This will allow us to step through the build process and pinpoint exactly where the file modification times are going awry. It’s much easier to debug a problem when you can see it happening right in front of you.
3. Developing a Robust Fix: Once we understand the root cause, we'll implement a fix that addresses the underlying problem, not just the symptoms. This might involve tweaking the make rules, adjusting file timestamps, or modifying the build process in some other way. The goal is to prevent this issue from recurring in the future. We're aiming for a long-term solution, not just a quick patch.
4. Improving Testing: We're also looking at ways to improve our testing process to catch these kinds of issues earlier. This might involve adding more checks for static linking or modifying our build pipeline to run tests in a more isolated environment. The more eyes we have on the process, the better.

Community Involvement

Your help and insights are always welcome! If you have any ideas or suggestions, please feel free to share them. We're all in this together, and the more brains we have working on the problem, the faster we'll find a solution. Whether you're a seasoned crystal developer or just starting out, your input is valuable. Open-source is all about collaboration, and we appreciate everyone who contributes.

How You Can Help

• Share Your Experiences: If you've encountered similar issues or have any insights into make and build processes, please let us know.
• Review the Changes: Take a look at the changes from yesterday's nightly build and see if anything jumps out at you.
• Test Potential Fixes: Once we have a potential fix, we'll need people to test it and make sure it resolves the issue without introducing new problems.

Staying Updated

We'll keep you updated on our progress as we work to resolve this issue. Check back here for updates, and feel free to ask any questions you have. We're committed to keeping the crystal builds stable and reliable, and we appreciate your patience as we work through this. We value transparency, and we want you to know what’s going on every step of the way.

Thanks for your understanding, and let's get this fixed!