The cache-tree optimization originally helped speed up write-tree
operation. However, many commands no longer properly maintain -- or
use an opportunity to cheaply generate -- the cache-tree data. In
particular, this affects commit, checkout and reset. The notable
examples that *do* write cache-tree data are read-tree and write-tree.
This sadly means most people no longer benefit from the optimization,
as they would not normally use the plumbing commands.
Document the current state of affairs in a test file, in preparation
for improvements in the area.
Signed-off-by: Thomas Rast <trast@xxxxxxxxxxxxxxx>
---
t/t0090-cache-tree.sh | 95 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 95 insertions(+), 0 deletions(-)
create mode 100755 t/t0090-cache-tree.sh
diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
new file mode 100755
index 0000000..3d0702a
--- /dev/null
+++ b/t/t0090-cache-tree.sh
@@ -0,0 +1,95 @@
+#!/bin/sh
+
+test_description="Test whether cache-tree is properly updated
+
+Tests whether various commands properly update and/or rewrite the
+cache-tree extension.
+"
+ . ./test-lib.sh
+
+cmp_cache_tree () {
+ test-dump-cache-tree >actual &&
+ sed "s/$_x40/SHA/" <actual >filtered &&
+ test_cmp "$1" filtered
+}
+
+# We don't bother with actually checking the SHA1:
+# test-dump-cache-tree already verifies that all existing data is
+# correct.
+test_shallow_cache_tree () {
+ echo "SHA " \
+ "($(git ls-files|wc -l) entries, 0 subtrees)" >expect &&
+ cmp_cache_tree expect
+}
+
+test_invalid_cache_tree () {
+ echo "invalid (0 subtrees)" >expect &&
+ echo "SHA #(ref) " \
+ "($(git ls-files|wc -l) entries, 0 subtrees)" >>expect &&
+ cmp_cache_tree expect
+}
+
+test_no_cache_tree () {
+ : >expect &&
+ cmp_cache_tree expect
+}
+
+test_expect_failure 'initial commit has cache-tree' '
+ test_commit foo &&
+ test_shallow_cache_tree
+'
+
+test_expect_success 'read-tree HEAD establishes cache-tree' '
+ git read-tree HEAD &&
+ test_shallow_cache_tree
+'
+
+test_expect_success 'git-add invalidates cache-tree' '
+ test_when_finished "git reset --hard; git read-tree HEAD" &&
+ echo "I changed this file" > foo &&
+ git add foo &&
+ test_invalid_cache_tree
+'
+
+test_expect_success 'update-index invalidates cache-tree' '
+ test_when_finished "git reset --hard; git read-tree HEAD" &&
+ echo "I changed this file" > foo &&
+ git update-index --add foo &&
+ test_invalid_cache_tree
+'
+
+test_expect_success 'write-tree establishes cache-tree' '
+ test-scrap-cache-tree &&
+ git write-tree &&
+ test_shallow_cache_tree
+'
+
+test_expect_success 'test-scrap-cache-tree works' '
+ git read-tree HEAD &&
+ test-scrap-cache-tree &&
+ test_no_cache_tree
+'
+
+test_expect_failure 'second commit has cache-tree' '
+ test_commit bar &&
+ test_shallow_cache_tree
+'
+
+test_expect_failure 'reset --hard gives cache-tree' '
+ test-scrap-cache-tree &&
+ git reset --hard &&
+ test_shallow_cache_tree
+'
+
+test_expect_failure 'reset --hard without index gives cache-tree' '
+ rm -f .git/index &&
+ git reset --hard &&
+ test_shallow_cache_tree
+'
+
+test_expect_failure 'checkout gives cache-tree' '
+ git checkout HEAD^ &&
+ test_shallow_cache_tree
+'
+
+test_done
--
1.7.8.425.ga639d3
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