Create chapter about rust-lang/rust issue triaging

This explains some of the existing processes around triage, and how I do
it.

Author: Noratrieb

src/SUMMARY.md

@@ -103,6 +103,7 @@
     - [Release Process](./release/process.md)
     - [Rollup Procedure](./release/rollups.md)
     - [Triage Procedure](./release/triage-procedure.md)
+    - [Issue Triaging](./release/issue-triaging.md)
     - [Triaging Crater Runs](./release/crater.md)
 - [Archive](./archive/README.md)
     - [Friends of the Tree](./archive/fott.md)

src/release/issue-triaging.md

@@ -0,0 +1,80 @@
+# Issue triaging
+
+This page is about the `rust-lang/rust` repository. Other repositories may have different processes.
+
+Tracking issues (label `C-tracking-issue`) don't fit into this procedure and are treated differently.
+
+## Motivation
+
+The `rust-lang/rust` repository has thousands of issues and hundreds of people working on it.
+It is impossible for all people to check and solve issues. The goals of triaging are connecting
+issues to the relevant people, and helping them be more effective at fixing the issue.
+
+In practice, it is unrealistic for all issues to be solved quickly and found the by right people.
+Through applications of labels we make the issue tracker more searchable for future reference,
+so that people in the future have an easier time finding related issues or issues they are interested
+in working on.
+
+Triaging can be done by **everyone**, no matter your permissions. We encourage everyone to help here,
+as triaging work is highly parallelizable and easy to get started with.
+
+## Initial triaging
+
+When an issue is opened, it gets the `needs-triage` label. This ensures that every issue gets an initial
+look and that no issue is forgotten, or that when it is forgotten, it is at least visibly forgotten by still having the label.
+
+`needs-triage` is an initial checkpoint. The effort needed to get an issue past the label should be minimal.
+
+To do the initial triage and remove the `needs-triage` label, the following conditions should be fulfilled/considered.
+It's okay if not all of these are always considered, treat it as guideline, not a hard check list. It is also not exhaustive.
+
+- The issue should make sense, that is it should present a problem.
+    - For example, if an issue is a question about Rust in general, the issue should be closed and the user redicted to URLO/Discord.
+      You can of course answer the question too :) (but make sure to mention that the user should go to URLO/Discord next time).
+- Add appropriate labels ([Labels](#labels))
+    - Specifically, `T-*` and `C-*` are the most relevant
+- If the issue contains no reproduction but needs one, ask for one and add the `S-needs-repro` label
+- If the issue could benefit from bisecting the regression, add `E-needs-bisection` (or do the bisection yourself)
+- Does this issue require nightly? Add `requires-nightly`.
+- Is the issue a regression? Apply the `regression-untriaged` label (or figure out what regression it is exactly)
+- If you happen to know people who this issue is relevant to, ping them.
+    - For example, write `cc @ThatPerson` if `ThatPerson` has been working a lot on the problematic feature recently
+- Does this issue require incomplete or internal features? Add `requires-{incomplete,internal}-features`.
+
+For applying and removing labels, unprivileged users can use rustbot.
+For example, `@rustbot label +T-compiler +C-bug +A-linkage +O-macos -needs-triage`.
+
+To see a list of all labels, check out the "labels" page next to the search bar in the issue tracker.
+
+## Further triaging
+
+For issues that have been through the initial triaging step (that is, don't have the `needs-triage` label anymore), there are usually
+still things that can be improved. There are often many more labels that could be applied (using rustbot again if you don't have privileges).
+
+Additionally, old (there is no clear definition of old yet, but something on the order of months) `S-needs-repro` issues can be closed
+if there is no way to make progress without a reproduction. This requires privileges, but if you don't have them, you can just link the issue
+on Zulip (for example in `t-release/triage` or `general`) and someone with privileges can close it for you.
+
+Another useful thing to do is go through `E-needs-mcve` and `E-needs-bisection` issues and creating minimizations or bisecting the issue
+(using [cargo-bisect-rustc](`https://github.com/rust-lang/cargo-bisect-rustc`)). When you provide one, you can also remove the label
+using rustbot (`@rustbot label -E-needs-bisection`).
+
+## Labels
+
+There are many different labels that can be applied to issues.
+
+- `needs-triage`: signals that an issue is new and needs initial triage
+- `T-*`: Specifies the team or teams that this issue is relevant to, for example compiler, types or libs
+- `C-*`: Specifies the category of the label, for example a bug, tracking issue or discussion
+- `O-*`: For platform-specific issues, specifies the platform (architecture or operating system). For example macos, aarch64, windows
+- `A-*`: The areas that the issue is relevant to, for example linkage, patterns, diagnostics
+- `F-*`: When the issue concerns a specific (usually unstable) feature
+- `requires-nightly`: This issue is not relevant to the stable compiler
+- `requires-{incomplete,internal}-features`: This issue requires an incomplete or internal feature. The latter often means that the issue
+    should be closed in accordance with compiler [MCP 620](https://github.com/rust-lang/compiler-team/issues/620).
+- `regression-*`: Labels for tracking issues that are regressions.
+- `D-*`: Labels for diagnostics issue.
+- `I-*`: Different labels about the nature (originally, importance) of a bug. For example ICE, slow code, heavy code, crashes, unsoundness.
+- `P-*`: Priority labels. Applied using the [Compiler Prioritization procedure](../compiler/prioritization.md)
+- `S-*`: The status of an issue, for example S-needs-repro.
+- `E-*`: Calls for participation, for example to minimize an issue (E-needs-mcve) or because there is mentoring available (E-mentor).