Merge pull request #268 from swiftlang/ahoppen-patch-1

Fix incorrect command in Reducing Stress Tester Failures.md

Author: ahoppen

SourceKitStressTester/Documentation/Reducing Stress Tester Failures.md

@@ -12,7 +12,7 @@ If the SourceKit stress tester job fails, this guide describes how to generate r
 6. Add `--print-requests` to the `sk-stress-test` invocation and let it run until you see something like `sourcekit: [1:connection-event-handler:9731: 0.0000] Connection interrupt`. Copy the request YAML and save it to `/tmp/req.yml`
 7. Run this request standalone using `/Library/Developer/Toolchains/swift-latest.xctoolchain/usr/bin/sourcekit-lsp debug run-sourcekitd-request --request-file /tmp/req.yml`
   - If this does not reproduce the failure, the previous requests executed by `sk-stress-test` are needed to hit it. Extracting all of them (`split -p '^{' input.txt` is a good command) and then pass them to `sourcekit-lsp debug run-sourcekitd-request` by passing `--request-file` multiple times.
-8. If a single request hits the failure and it is a crash, `/Library/Developer/Toolchains/swift-latest.xctoolchain/usr/bin/sourcekit-lsp debug run-sourcekitd-request --request-file /tmp/req.yml` can automatically reduce the majority of the failure, a few manual reduction steps usually help towards the end. Otherwise you have to reduce it manually. The `--position` parameter to `sourcekit-lsp debug run-sourcekitd-request` can override the position in the request so you don’t have to do offset calculations.
+8. If a single request hits the failure and it is a crash, `/Library/Developer/Toolchains/swift-latest.xctoolchain/usr/bin/sourcekit-lsp debug reduce --request-file /tmp/req.yml` can automatically reduce the majority of the failure, a few manual reduction steps usually help towards the end. Otherwise you have to reduce it manually. The `--position` parameter to `sourcekit-lsp debug run-sourcekitd-request` can override the position in the request so you don’t have to do offset calculations.
 9. Build `sourcekitd-test` locally and create a lit test that reproduces the failure. Depending on the crash, it might be possible to reproduce the failure with `swift-frontend` alone.
 10. Depending on the failure, bisect the `swift` repository to find the commit that introduced the failure or determine the likely cause of the failure by looking at the git history between the last successful and the first failing stress tester run.
 11. File an issue with the lit test at https://github.com/swiftlang/swift and attach the `found by stress tester` label.