Merge branch 'sg/split-index-racefix'

The codepath to support the experimental split-index mode had
remaining "racily clean" issues fixed.

* sg/split-index-racefix:
  split-index: BUG() when cache entry refers to non-existing shared entry
  split-index: smudge and add racily clean cache entries to split index
  split-index: don't compare cached data of entries already marked for split index
  split-index: count the number of deleted entries
  t1700-split-index: date back files to avoid racy situations
  split-index: add tests to demonstrate the racy split index problem
  t1700-split-index: document why FSMONITOR is disabled in this test script

1 files changed, 28 insertions, 21 deletions

diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index 3e618cad12..2ac47aa0e4 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -13,6 +13,13 @@ sane_unset GIT_TEST_SPLIT_INDEX
 sane_unset GIT_TEST_FSMONITOR
 sane_unset GIT_TEST_INDEX_THREADS
 
+# Create a file named as $1 with content read from stdin.
+# Set the file's mtime to a few seconds in the past to avoid racy situations.
+create_non_racy_file () {
+	cat >"$1" &&
+	test-tool chmtime =-5 "$1"
+}
+
 test_expect_success 'enable split index' '
 	git config splitIndex.maxPercentChange 100 &&
 	git update-index --split-index &&
@@ -36,7 +43,7 @@ test_expect_success 'enable split index' '
 '
 
 test_expect_success 'add one file' '
-	: >one &&
+	create_non_racy_file one &&
 	git update-index --add one &&
 	git ls-files --stage >ls-files.actual &&
 	cat >ls-files.expect <<-EOF &&
@@ -88,7 +95,7 @@ test_expect_success 'enable split index again, "one" now belongs to base index"'
 '
 
 test_expect_success 'modify original file, base index untouched' '
-	echo modified >one &&
+	echo modified | create_non_racy_file one &&
 	git update-index one &&
 	git ls-files --stage >ls-files.actual &&
 	cat >ls-files.expect <<-EOF &&
@@ -107,7 +114,7 @@ test_expect_success 'modify original file, base index untouched' '
 '
 
 test_expect_success 'add another file, which stays index' '
-	: >two &&
+	create_non_racy_file two &&
 	git update-index --add two &&
 	git ls-files --stage >ls-files.actual &&
 	cat >ls-files.expect <<-EOF &&
@@ -160,7 +167,7 @@ test_expect_success 'remove file in base index' '
 '
 
 test_expect_success 'add original file back' '
-	: >one &&
+	create_non_racy_file one &&
 	git update-index --add one &&
 	git ls-files --stage >ls-files.actual &&
 	cat >ls-files.expect <<-EOF &&
@@ -179,7 +186,7 @@ test_expect_success 'add original file back' '
 '
 
 test_expect_success 'add new file' '
-	: >two &&
+	create_non_racy_file two &&
 	git update-index --add two &&
 	git ls-files --stage >actual &&
 	cat >expect <<-EOF &&
@@ -223,7 +230,7 @@ test_expect_success 'rev-parse --shared-index-path' '
 
 test_expect_success 'set core.splitIndex config variable to true' '
 	git config core.splitIndex true &&
-	: >three &&
+	create_non_racy_file three &&
 	git update-index --add three &&
 	git ls-files --stage >ls-files.actual &&
 	cat >ls-files.expect <<-EOF &&
@@ -258,9 +265,9 @@ test_expect_success 'set core.splitIndex config variable to false' '
 	test_cmp expect actual
 '
 
-test_expect_success 'set core.splitIndex config variable to true' '
+test_expect_success 'set core.splitIndex config variable back to true' '
 	git config core.splitIndex true &&
-	: >three &&
+	create_non_racy_file three &&
 	git update-index --add three &&
 	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
@@ -270,7 +277,7 @@ test_expect_success 'set core.splitIndex config variable to true' '
 	deletions:
 	EOF
 	test_cmp expect actual &&
-	: >four &&
+	create_non_racy_file four &&
 	git update-index --add four &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
@@ -284,7 +291,7 @@ test_expect_success 'set core.splitIndex config variable to true' '
 
 test_expect_success 'check behavior with splitIndex.maxPercentChange unset' '
 	git config --unset splitIndex.maxPercentChange &&
-	: >five &&
+	create_non_racy_file five &&
 	git update-index --add five &&
 	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
@@ -294,7 +301,7 @@ test_expect_success 'check behavior with splitIndex.maxPercentChange unset' '
 	deletions:
 	EOF
 	test_cmp expect actual &&
-	: >six &&
+	create_non_racy_file six &&
 	git update-index --add six &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
 	cat >expect <<-EOF &&
@@ -308,7 +315,7 @@ test_expect_success 'check behavior with splitIndex.maxPercentChange unset' '
 
 test_expect_success 'check splitIndex.maxPercentChange set to 0' '
 	git config splitIndex.maxPercentChange 0 &&
-	: >seven &&
+	create_non_racy_file seven &&
 	git update-index --add seven &&
 	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
@@ -318,7 +325,7 @@ test_expect_success 'check splitIndex.maxPercentChange set to 0' '
 	deletions:
 	EOF
 	test_cmp expect actual &&
-	: >eight &&
+	create_non_racy_file eight &&
 	git update-index --add eight &&
 	BASE=$(test-tool dump-split-index .git/index | grep "^base") &&
 	test-tool dump-split-index .git/index | sed "/^own/d" >actual &&
@@ -331,17 +338,17 @@ test_expect_success 'check splitIndex.maxPercentChange set to 0' '
 '
 
 test_expect_success 'shared index files expire after 2 weeks by default' '
-	: >ten &&
+	create_non_racy_file ten &&
 	git update-index --add ten &&
 	test $(ls .git/sharedindex.* | wc -l) -gt 2 &&
 	just_under_2_weeks_ago=$((5-14*86400)) &&
 	test-tool chmtime =$just_under_2_weeks_ago .git/sharedindex.* &&
-	: >eleven &&
+	create_non_racy_file eleven &&
 	git update-index --add eleven &&
 	test $(ls .git/sharedindex.* | wc -l) -gt 2 &&
 	just_over_2_weeks_ago=$((-1-14*86400)) &&
 	test-tool chmtime =$just_over_2_weeks_ago .git/sharedindex.* &&
-	: >twelve &&
+	create_non_racy_file twelve &&
 	git update-index --add twelve &&
 	test $(ls .git/sharedindex.* | wc -l) -le 2
 '
@@ -349,12 +356,12 @@ test_expect_success 'shared index files expire after 2 weeks by default' '
 test_expect_success 'check splitIndex.sharedIndexExpire set to 16 days' '
 	git config splitIndex.sharedIndexExpire "16.days.ago" &&
 	test-tool chmtime =$just_over_2_weeks_ago .git/sharedindex.* &&
-	: >thirteen &&
+	create_non_racy_file thirteen &&
 	git update-index --add thirteen &&
 	test $(ls .git/sharedindex.* | wc -l) -gt 2 &&
 	just_over_16_days_ago=$((-1-16*86400)) &&
 	test-tool chmtime =$just_over_16_days_ago .git/sharedindex.* &&
-	: >fourteen &&
+	create_non_racy_file fourteen &&
 	git update-index --add fourteen &&
 	test $(ls .git/sharedindex.* | wc -l) -le 2
 '
@@ -363,13 +370,13 @@ test_expect_success 'check splitIndex.sharedIndexExpire set to "never" and "now"
 	git config splitIndex.sharedIndexExpire never &&
 	just_10_years_ago=$((-365*10*86400)) &&
 	test-tool chmtime =$just_10_years_ago .git/sharedindex.* &&
-	: >fifteen &&
+	create_non_racy_file fifteen &&
 	git update-index --add fifteen &&
 	test $(ls .git/sharedindex.* | wc -l) -gt 2 &&
 	git config splitIndex.sharedIndexExpire now &&
 	just_1_second_ago=-1 &&
 	test-tool chmtime =$just_1_second_ago .git/sharedindex.* &&
-	: >sixteen &&
+	create_non_racy_file sixteen &&
 	git update-index --add sixteen &&
 	test $(ls .git/sharedindex.* | wc -l) -le 2
 '
@@ -384,7 +391,7 @@ do
 		# Create one new shared index file
 		git config core.sharedrepository "$mode" &&
 		git config core.splitIndex true &&
-		: >one &&
+		create_non_racy_file one &&
 		git update-index --add one &&
 		echo "$modebits" >expect &&
 		test_modebits .git/index >actual &&