Subject: [PATCH v9 19/30] fsm-listen-darwin: shutdown daemon if worktree root is moved/renamed

From: "Jeff Hostetler via GitGitGadget" <[email-masked]>
Date: Thu, 26 May 2022 21:47:13 +0000

From: Jeff Hostetler <[email-masked]>

Teach the listener thread to shutdown the daemon if the spelling of the
worktree root directory changes.

Signed-off-by: Jeff Hostetler <[email-masked]>
---
 compat/fsmonitor/fsm-listen-darwin.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/compat/fsmonitor/fsm-listen-darwin.c b/compat/fsmonitor/fsm-listen-darwin.c
index 07113205a61..83d38e8ac6c 100644
--- a/compat/fsmonitor/fsm-listen-darwin.c
+++ b/compat/fsmonitor/fsm-listen-darwin.c
@@ -106,6 +106,11 @@ static void log_flags_set(const char *path, const FSEventStreamEventFlags flag)
 	strbuf_release(&msg);
 }
 
+static int ef_is_root_changed(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagRootChanged);
+}
+
 static int ef_is_root_delete(const FSEventStreamEventFlags ef)
 {
 	return (ef & kFSEventStreamEventFlagItemIsDir &&
@@ -215,6 +220,26 @@ static void fsevent_callback(ConstFSEventStreamRef streamRef,
 			continue;
 		}
 
+		if (ef_is_root_changed(event_flags[k])) {
+			/*
+			 * The spelling of the pathname of the root directory
+			 * has changed.  This includes the name of the root
+			 * directory itself or of any parent directory in the
+			 * path.
+			 *
+			 * (There may be other conditions that throw this,
+			 * but I couldn't find any information on it.)
+			 *
+			 * Force a shutdown now and avoid things getting
+			 * out of sync.  The Unix domain socket is inside
+			 * the .git directory and a spelling change will make
+			 * it hard for clients to rendezvous with us.
+			 */
+			trace_printf_key(&trace_fsmonitor,
+					 "event: root changed");
+			goto force_shutdown;
+		}
+
 		if (ef_ignore_xattr(event_flags[k])) {
 			trace_printf_key(&trace_fsmonitor,
 					 "ignore-xattr: '%s', flags=0x%x",
-- 
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