Inconsistent behavior between search and sidebar when modeline overrides language specified by extension

[varungandhi-src]

Related items:

• https://github.com/sourcegraph/sourcegraph/pull/59234 - I made the code first check the extension to avoid fetching the file contents (because that can be slow)
• https://github.com/sourcegraph/sourcegraph/issues/60341

Search query in screenshot, file in screenshot

One possible fix here would be that once we have a high performance API for fetching file contents (Slack discussion)

• https://github.com/sourcegraph/sourcegraph/issues/60659

we can also do content-based language detection for the icons and ensure consistent behavior.

As a quick spot check, I went through ~10 different files which have a C++ modeline but a C extension, and all of them seem to actually be valid C and not using any C++ features. So I'm not sure why they got marked as C++ with the modeline. 🤷🏽 However, I'd argue that the discrepancy is still confusing.

/cc @sourcegraph/search-platform

[jtibshirani]

As a tactical fix, I wonder if we should remove the modeline detection in our go-enry wrapper? I'd be really curious to understand how much it helps in practice.

[varungandhi-src]

I don't think we should remove the modeline detection because people use that a bunch in practice. Here's an example query for Python.