From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
On Windows, teach FSMonitor to recognize the shortname of ".git"
as an alias for ".git".
Sometimes we receive FS events using the shortname, such as when
a CMD shell runs "RENAME GIT~1 FOO" or "RMDIR GIT~1". The FS
notification arrives using whatever combination of long and
shortnames used by the other process. (Shortnames do seem to
be case normalized, however.)
NEEDSWORK: This only addresses the case of removing or renaming
the ".git" directory using the shortname alias, so that the daemon
properly shuts down. I'm leaving it a task for later to handle
the general case of shortnames and report them to the fsmonitor
client process. This would include tracked and untracked paths
that just happen to have a shortname alias.
Signed-off-by: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
---
compat/fsmonitor/fsmonitor-fs-listen-win32.c | 192 +++++++++++++++----
t/t7527-builtin-fsmonitor.sh | 65 +++++++
2 files changed, 217 insertions(+), 40 deletions(-)
diff --git a/compat/fsmonitor/fsmonitor-fs-listen-win32.c b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
index d707d47a0d7..f2ea5940790 100644
--- a/compat/fsmonitor/fsmonitor-fs-listen-win32.c
+++ b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
@@ -48,6 +48,8 @@ struct fsmonitor_daemon_backend_data
#define LISTENER_HAVE_DATA_WORKTREE 1
#define LISTENER_HAVE_DATA_GITDIR 2
int nr_listener_handles;
+
+ struct strbuf dot_git_shortname;
};
/*
@@ -250,6 +252,62 @@ static void cancel_rdcw_watch(struct one_watch *watch)
watch->is_active = FALSE;
}
+/*
+ * Process a single relative pathname event.
+ * Return 1 if we should shutdown.
+ */
+static int process_1_worktree_event(
+ FILE_NOTIFY_INFORMATION *info,
+ struct string_list *cookie_list,
+ struct fsmonitor_batch **batch,
+ const struct strbuf *path,
+ enum fsmonitor_path_type t)
+{
+ const char *slash;
+
+ switch (t) {
+ case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX:
+ /* special case cookie files within .git */
+
+ /* Use just the filename of the cookie file. */
+ slash = find_last_dir_sep(path->buf);
+ string_list_append(cookie_list,
+ slash ? slash + 1 : path->buf);
+ break;
+
+ case IS_INSIDE_DOT_GIT:
+ /* ignore everything inside of "<worktree>/.git/" */
+ break;
+
+ case IS_DOT_GIT:
+ /* "<worktree>/.git" was deleted (or renamed away) */
+ if ((info->Action == FILE_ACTION_REMOVED) ||
+ (info->Action == FILE_ACTION_RENAMED_OLD_NAME)) {
+ trace2_data_string("fsmonitor", NULL,
+ "fsm-listen/dotgit",
+ "removed");
+ return 1;
+ }
+ break;
+
+ case IS_WORKDIR_PATH:
+ /* queue normal pathname */
+ if (!*batch)
+ *batch = fsmonitor_batch__new();
+ fsmonitor_batch__add_path(*batch, path->buf);
+ break;
+
+ case IS_GITDIR:
+ case IS_INSIDE_GITDIR:
+ case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
+ default:
+ BUG("unexpected path classification '%d' for '%s'",
+ t, path->buf);
+ }
+
+ return 0;
+}
+
/*
* Process filesystem events that happen anywhere (recursively) under the
* <worktree> root directory. For a normal working directory, this includes
@@ -294,7 +352,6 @@ static int process_worktree_events(struct fsmonitor_daemon_state *state)
*/
for (;;) {
FILE_NOTIFY_INFORMATION *info = (void *)p;
- const char *slash;
enum fsmonitor_path_type t;
strbuf_reset(&path);
@@ -303,45 +360,45 @@ static int process_worktree_events(struct fsmonitor_daemon_state *state)
t = fsmonitor_classify_path_workdir_relative(path.buf);
- switch (t) {
- case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX:
- /* special case cookie files within .git */
-
- /* Use just the filename of the cookie file. */
- slash = find_last_dir_sep(path.buf);
- string_list_append(&cookie_list,
- slash ? slash + 1 : path.buf);
- break;
-
- case IS_INSIDE_DOT_GIT:
- /* ignore everything inside of "<worktree>/.git/" */
- break;
-
- case IS_DOT_GIT:
- /* "<worktree>/.git" was deleted (or renamed away) */
- if ((info->Action == FILE_ACTION_REMOVED) ||
- (info->Action == FILE_ACTION_RENAMED_OLD_NAME)) {
- trace2_data_string("fsmonitor", NULL,
- "fsm-listen/dotgit",
- "removed");
- goto force_shutdown;
- }
- break;
-
- case IS_WORKDIR_PATH:
- /* queue normal pathname */
- if (!batch)
- batch = fsmonitor_batch__new();
- fsmonitor_batch__add_path(batch, path.buf);
- break;
-
- case IS_GITDIR:
- case IS_INSIDE_GITDIR:
- case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
- default:
- BUG("unexpected path classification '%d' for '%s'",
- t, path.buf);
- }
+ if (process_1_worktree_event(info, &cookie_list, &batch,
+ &path, t))
+ goto force_shutdown;
+
+ /*
+ * NEEDSWORK: If `path` contains a shortname (that is,
+ * if any component within it is a shortname), we
+ * should expand it to a longname (See
+ * `GetLongPathNameW()`) and re-normalize, classify,
+ * and process it because our client is probably
+ * expecting "normal" paths.
+ *
+ * HOWEVER, if our process has called `chdir()` to get
+ * us out of the root of the worktree (so that the
+ * root directory is not busy), then we have to be
+ * careful to convert the paths in the INFO array
+ * (which are relative to the directory of the RDCW
+ * watch and not the CWD) into absolute paths before
+ * calling GetLongPathNameW() and then convert the
+ * computed value back to a RDCW-relative pathname
+ * (which is what we and the client expect).
+ *
+ * FOR NOW, just handle case (1) exactly so that we
+ * shutdown properly when ".git" is deleted via the
+ * shortname alias.
+ *
+ * We might see case (2) events for cookie files, but
+ * we can ignore them.
+ *
+ * FOR LATER, handle case (3) where the worktree
+ * events contain shortnames. We should convert
+ * them to longnames to avoid confusing the client.
+ */
+ if (data->dot_git_shortname.len &&
+ !strcmp(path.buf, data->dot_git_shortname.buf) &&
+ process_1_worktree_event(info, &cookie_list, &batch,
+ &data->dot_git_shortname,
+ IS_DOT_GIT))
+ goto force_shutdown;
skip_this_path:
if (!info->NextEntryOffset)
@@ -415,6 +472,14 @@ static int process_gitdir_events(struct fsmonitor_daemon_state *state)
t, path.buf);
}
+ /*
+ * WRT shortnames, this external gitdir will not see
+ * case (1) nor case (3) events.
+ *
+ * We might see case (2) events for cookie files, but
+ * we can ignore them.
+ */
+
skip_this_path:
if (!info->NextEntryOffset)
break;
@@ -493,6 +558,7 @@ clean_shutdown:
int fsmonitor_fs_listen__ctor(struct fsmonitor_daemon_state *state)
{
struct fsmonitor_daemon_backend_data *data;
+ char shortname[16]; /* a padded 8.3 buffer */
CALLOC_ARRAY(data, 1);
@@ -523,6 +589,52 @@ int fsmonitor_fs_listen__ctor(struct fsmonitor_daemon_state *state)
data->nr_listener_handles++;
}
+ /*
+ * NEEDSWORK: Properly handle 8.3 shortnames. RDCW events can
+ * contain a shortname (if another application uses a
+ * shortname in a system call). We care about aliasing and
+ * the use of shortnames for:
+ *
+ * (1) ".git",
+ * -- if an external process deletes ".git" using "GIT~1",
+ * we need to catch that and shutdown.
+ *
+ * (2) our cookie files,
+ * -- if an external process deletes one of our cookie
+ * files using a shortname, we will get a shortname
+ * event for it. However, we should have already
+ * gotten a longname event for it when we created the
+ * cookie, so we can safely discard the shortname
+ * events for cookie files.
+ *
+ * (3) the spelling of modified files that we report to clients.
+ * -- we need to report the longname to the client because
+ * that is what they are expecting. Presumably, the
+ * client is going to lookup the paths that we report
+ * in their index and untracked-cache, so we should
+ * normalize the data for them. (Technically, they
+ * could adapt, so we could relax this maybe.)
+ *
+ * FOR NOW, while our CWD is at the root of the worktree we
+ * can easily get the spelling of the shortname of ".git" (if
+ * the volume has shortnames enabled). For most worktrees
+ * this value will be "GIT~1", but we don't want to assume
+ * that.
+ *
+ * Capture this so that we can handle (1).
+ *
+ * We leave (3) for a future effort.
+ */
+ strbuf_init(&data->dot_git_shortname, 0);
+ GetShortPathNameA(".git", shortname, sizeof(shortname));
+ if (!strcmp(".git", shortname))
+ trace_printf_key(&trace_fsmonitor, "No shortname for '.git'");
+ else {
+ trace_printf_key(&trace_fsmonitor,
+ "Shortname of '.git' is '%s'", shortname);
+ strbuf_addstr(&data->dot_git_shortname, shortname);
+ }
+
state->backend_data = data;
return 0;
diff --git a/t/t7527-builtin-fsmonitor.sh b/t/t7527-builtin-fsmonitor.sh
index d1832702397..b166b4a0a31 100755
--- a/t/t7527-builtin-fsmonitor.sh
+++ b/t/t7527-builtin-fsmonitor.sh
@@ -113,6 +113,71 @@ test_expect_success 'implicit daemon stop (rename .git)' '
test_must_fail git -C test_implicit_2 fsmonitor--daemon status
'
+# File systems on Windows may or may not have shortnames.
+# This is a volume-specific setting on modern systems.
+# "C:/" drives are required to have them enabled. Other
+# hard drives default to disabled.
+#
+# This is a crude test to see if shortnames are enabled
+# on the volume containing the test directory. It is
+# crude, but it does not require elevation like `fsutil`.
+#
+test_lazy_prereq SHORTNAMES '
+ mkdir .foo &&
+ test -d "FOO~1"
+'
+
+# Here we assume that the shortname of ".git" is "GIT~1".
+test_expect_success MINGW,SHORTNAMES 'implicit daemon stop (rename GIT~1)' '
+ test_when_finished "stop_daemon_delete_repo test_implicit_1s" &&
+
+ git init test_implicit_1s &&
+
+ start_daemon test_implicit_1s &&
+
+ # renaming the .git directory will implicitly stop the daemon.
+ # this moves {.git, GIT~1} to {.gitxyz, GITXYZ~1}.
+ # the rename-from FS Event will contain the shortname.
+ #
+ mv test_implicit_1s/GIT~1 test_implicit_1s/.gitxyz &&
+
+ sleep 1 &&
+ # put it back so that our status will not crawl out to our
+ # parent directory.
+ # this moves {.gitxyz, GITXYZ~1} to {.git, GIT~1}.
+ mv test_implicit_1s/.gitxyz test_implicit_1s/.git &&
+
+ test_must_fail git -C test_implicit_1s fsmonitor--daemon status
+'
+
+# Here we first create a file with LONGNAME of "GIT~1" before
+# we create the repo. This will cause the shortname of ".git"
+# to be "GIT~2".
+test_expect_success MINGW,SHORTNAMES 'implicit daemon stop (rename GIT~2)' '
+ test_when_finished "stop_daemon_delete_repo test_implicit_1s2" &&
+
+ mkdir test_implicit_1s2 &&
+ echo HELLO >test_implicit_1s2/GIT~1 &&
+ git init test_implicit_1s2 &&
+
+ [ -f test_implicit_1s2/GIT~1 ] &&
+ [ -d test_implicit_1s2/GIT~2 ] &&
+
+ start_daemon test_implicit_1s2 &&
+
+ # renaming the .git directory will implicitly stop the daemon.
+ # the rename-from FS Event will contain the shortname.
+ #
+ mv test_implicit_1s2/GIT~2 test_implicit_1s2/.gitxyz &&
+
+ sleep 1 &&
+ # put it back so that our status will not crawl out to our
+ # parent directory.
+ mv test_implicit_1s2/.gitxyz test_implicit_1s2/.git &&
+
+ test_must_fail git -C test_implicit_1s2 fsmonitor--daemon status
+'
+
test_expect_success 'cannot start multiple daemons' '
test_when_finished "stop_daemon_delete_repo test_multiple" &&
--
gitgitgadget
