[PATCH 3/6] fsmonitor: Update helper tool, now that flags are filled later

[Alex Vandiver <alexmv@dropbox.com>]

dd9005a0a ("fsmonitor: delay updating state until after split index is
merged", 2017-10-27) began deferring the setting of the
CE_FSMONITOR_VALID flag until later, such that do_read_index() does
not perform those steps.  This means that t/helper/test-dump-fsmonitor
showed all bits as always unset.

Split out the code which inflates the ewah into CE_FSMONITOR_VALID
bits, and call that from t/helper/test-dump-fsmonitor.  We cannot
simply switch the code to call read_index_from or the more specific
tweak_fsmonitor, because the latter would modify the extension state
by calling add_fsmonitor.

Signed-off-by: Alex Vandiver <alexmv@dropbox.com>
---
 fsmonitor.c                    | 9 ++++++++-
 fsmonitor.h                    | 6 ++++++
 t/helper/test-dump-fsmonitor.c | 2 ++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/fsmonitor.c b/fsmonitor.c
index 0af7c4edb..7011dff15 100644
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@ -227,7 +227,7 @@ void remove_fsmonitor(struct index_state *istate)
 	}
 }
 
-void tweak_fsmonitor(struct index_state *istate)
+void inflate_fsmonitor_ewah(struct index_state *istate)
 {
 	int i;
 	int fsmonitor_enabled = git_config_get_fsmonitor();
@@ -250,6 +250,13 @@ void tweak_fsmonitor(struct index_state *istate)
 		ewah_free(istate->fsmonitor_dirty);
 		istate->fsmonitor_dirty = NULL;
 	}
+}
+
+void tweak_fsmonitor(struct index_state *istate)
+{
+	int fsmonitor_enabled = git_config_get_fsmonitor();
+
+	inflate_fsmonitor_ewah(istate);
 
 	switch (fsmonitor_enabled) {
 	case -1: /* keep: do nothing */
diff --git a/fsmonitor.h b/fsmonitor.h
index 5f68ca4d2..619852d4b 100644
--- a/fsmonitor.h
+++ b/fsmonitor.h
@@ -28,6 +28,12 @@ extern void write_fsmonitor_extension(struct strbuf *sb, struct index_state *ist
 extern void add_fsmonitor(struct index_state *istate);
 extern void remove_fsmonitor(struct index_state *istate);
 
+/*
+ * Inflate the fsmonitor_dirty ewah into the CE_FSMONITOR_VALID bits.
+ * Called by tweak_fsmonitor.
+ */
+extern void inflate_fsmonitor_ewah(struct index_state *istate);
+
 /*
  * Add/remove the fsmonitor index extension as necessary based on the current
  * core.fsmonitor setting.
diff --git a/t/helper/test-dump-fsmonitor.c b/t/helper/test-dump-fsmonitor.c
index ad452707e..53b19b39b 100644
--- a/t/helper/test-dump-fsmonitor.c
+++ b/t/helper/test-dump-fsmonitor.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "fsmonitor.h"
 
 int cmd_main(int ac, const char **av)
 {
@@ -8,6 +9,7 @@ int cmd_main(int ac, const char **av)
 	setup_git_directory();
 	if (do_read_index(istate, get_index_file(), 0) < 0)
 		die("unable to read index file");
+	inflate_fsmonitor_ewah(istate);
 	if (!istate->fsmonitor_last_update) {
 		printf("no fsmonitor\n");
 		return 0;
-- 
2.15.1.626.gc4617b774