Teach rustc to use OSC8 on nightly / Embedded links in terminal output

[estebank]

Proposal

Add a nightly flag -Zterminal-urls=y|on|yes|n|off|no|auto that configures enabling embedded links in terminal output. Start using this configuration only in nightly, defaulted to off. The specifics of auto will be determined through experimentation.

This will allow us to customize the printed output with hyperlinks to relevant documentation, or to local files (by using file://, but leveraging that can be fraught for people using ssh).

An example of what this would look like in practice can be seen in this video:

Screen.Recording.2023-02-08.at.11.44.15.AM.mov

rust-lang/rust#107838 shows what the code changes required would be.

Mentors or Reviewers

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Process

The main points of the Major Change Process are as follows:

• File an issue describing the proposal.
• A compiler team member or contributor who is knowledgeable in the area can second by writing @rustbot second.
  • Finding a "second" suffices for internal changes. If however, you are proposing a new public-facing feature, such as a -C flag, then full team check-off is required.
  • Compiler team members can initiate a check-off via @rfcbot fcp merge on either the MCP or the PR.
• Once an MCP is seconded, the Final Comment Period begins. If no objections are raised after 10 days, the MCP is considered approved.

You can read more about Major Change Proposals on forge.

Comments

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

[rustbot]

This issue is not meant to be used for technical discussion. There is a Zulip stream for that. Use this issue to leave procedural comments, such as volunteering to review, indicating that you second the proposal (or third, etc), or raising a concern that you would like to be addressed.

cc @rust-lang/compiler @rust-lang/compiler-contributors

[tmiasko]

@rustbot second

[apiraino]

@rustbot label -final-comment-period +major-change-accepted

[epage]

Is there a tracking issue for discussing this?

Cargo is stabilizing link support in 1.75 (see rust-lang/cargo#12889)

• We offer term.hyperlinks to control it
• We are auto-detecting with supports-hyperlinks
  • Unsure how we feel about the FORCE_HYPERLINK env variable; we aren't documenting it
  • We do have an extra check beyond that because a file path link wasn't correctly working on iTerm2
  • To drop is-terminal dep, I'm tempted to just copy/paste the code

It'd be good for cargo and rustc to coordinate on when links are shown (so one doesn't auto-detect when the other doesn't) and other behavior.

[estebank]

1. we should absolutely unify the behavior across rustc and cargo.
2. Be aware that "just" checking if the terminal supports hyperlinks is insufficient: if using a terminal sshing into a remote development machine, the links will either use the full ssh format (username@host:/path/to/file) or to a "fake" local path (/path/to/file/that/doesn't/exist/locally), breaking the currently working auto-linking that the VSCode terminal has. Are you certain that this is already correctly handled on the cargo side?

[epage]

For file: links, we include the hostname according to this gist