scm-prompt: add locked state

Summary:
If you're working n multiple terminals on the same repository, it is
often useful to know if a command you're about to run might block due to an
already-held lock on the repository. This upgrade to scm-prompt gives the
user this information.

Test Plan: updated the test

Reviewers: #fbhgext, stash

Reviewed By: #fbhgext, stash

Subscribers: stash

Differential Revision: https://phab.mercurial-scm.org/D790

scripts/scm-prompt.sh

@@ -108,6 +108,10 @@ _scm_prompt()
       extra="|REBASE"
     elif [[ -d "$hg/.hg/merge" ]]; then
       extra="|MERGE"
+    elif [[ -L "$hg/.hg/store/lock" ]]; then
+      extra="|STORE-LOCKED"
+    elif [[ -L "$hg/.hg/wlock" ]]; then
+      extra="|WDIR-LOCKED"
     fi
     local dirstate=$( \
       (test -f "$hg/.hg/dirstate" && \

tests/test-scm-prompt-hg.t

@@ -231,6 +231,16 @@ Test formatting options
   $ _scm_prompt ':%s:'
   :97af35b: (no-eol)
 
+Test locked repo states (generally due to concurrency so tests are kinda fake)
+  $ cmd ln -s "${HOSTNAME}:12345" .hg/wlock
+  (97af35b|WDIR-LOCKED)
+  $ cmd ln -s "${HOSTNAME}:12345" .hg/store/lock
+  (97af35b|STORE-LOCKED)
+  $ cmd rm .hg/wlock
+  (97af35b|STORE-LOCKED)
+  $ cmd rm .hg/store/lock
+  (97af35b)
+
 Test many remotenames
   $ hg log -r . -T '{node}\n'
   97af35b3648c0098cbd8114ae1b1bafab997ac20