When running a command like "git show" or "git diff" in a partial clone,
batch all missing blobs to be fetched as one request.
This is similar to c0c578b33c ("unpack-trees: batch fetching of missing
blobs", 2017-12-08), but for another command.
Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx>
---
Here's an improvement for those having partial clones.
I couldn't find a good place to place the test (a place that checks how
diff interfaces with the object store would be ideal), so I created a
new one. Let me know if there's a better place to put it.
---
diff.c | 27 +++++++++++++
t/t4067-diff-partial-clone.sh | 76 +++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+)
create mode 100755 t/t4067-diff-partial-clone.sh
diff --git a/diff.c b/diff.c
index ec5c095199..0e08d05b14 100644
--- a/diff.c
+++ b/diff.c
@@ -25,6 +25,7 @@
#include "packfile.h"
#include "parse-options.h"
#include "help.h"
+#include "fetch-object.h"
#ifdef NO_FAST_WORKING_DIRECTORY
#define FAST_WORKING_DIRECTORY 0
@@ -6067,6 +6068,32 @@ static void diff_flush_patch_all_file_pairs(struct diff_options *o)
if (o->color_moved)
o->emitted_symbols = &esm;
+ if (repository_format_partial_clone) {
+ /*
+ * Prefetch the diff pairs that are about to be flushed.
+ */
+ struct oid_array to_fetch = OID_ARRAY_INIT;
+ int fetch_if_missing_store = fetch_if_missing;
+
+ fetch_if_missing = 0;
+ for (i = 0; i < q->nr; i++) {
+ struct diff_filepair *p = q->queue[i];
+ if (!check_pair_status(p))
+ continue;
+ if (p->one && p->one->oid_valid &&
+ !has_object_file(&p->one->oid))
+ oid_array_append(&to_fetch, &p->one->oid);
+ if (p->two && p->two->oid_valid &&
+ !has_object_file(&p->two->oid))
+ oid_array_append(&to_fetch, &p->two->oid);
+ }
+ if (to_fetch.nr)
+ fetch_objects(repository_format_partial_clone,
+ to_fetch.oid, to_fetch.nr);
+ fetch_if_missing = fetch_if_missing_store;
+ oid_array_clear(&to_fetch);
+ }
+
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
if (check_pair_status(p))
diff --git a/t/t4067-diff-partial-clone.sh b/t/t4067-diff-partial-clone.sh
new file mode 100755
index 0000000000..38f03be114
--- /dev/null
+++ b/t/t4067-diff-partial-clone.sh
@@ -0,0 +1,76 @@
+#!/bin/sh
+
+test_description='behavior of diff when reading objects in a partial clone'
+
+. ./test-lib.sh
+
+test_expect_success 'git show batches blobs' '
+ test_create_repo server &&
+ echo a >server/a &&
+ echo b >server/b &&
+ git -C server add a b &&
+ git -C server commit -m x &&
+
+ test_config -C server uploadpack.allowfilter 1 &&
+ test_config -C server uploadpack.allowanysha1inwant 1 &&
+ git clone --bare --filter=blob:limit=0 "file://$(pwd)/server" client &&
+
+ # Ensure that there is exactly 1 negotiation by checking that there is
+ # only 1 "done" line sent. ("done" marks the end of negotiation.)
+ GIT_TRACE_PACKET="$(pwd)/trace" git -C client show HEAD &&
+ grep "git> done" trace >done_lines &&
+ test_line_count = 1 done_lines
+'
+
+test_expect_success 'diff batches blobs' '
+ rm -rf server client trace &&
+
+ test_create_repo server &&
+ echo a >server/a &&
+ echo b >server/b &&
+ git -C server add a b &&
+ git -C server commit -m x &&
+ echo c >server/c &&
+ echo d >server/d &&
+ git -C server add c d &&
+ git -C server commit -m x &&
+
+ test_config -C server uploadpack.allowfilter 1 &&
+ test_config -C server uploadpack.allowanysha1inwant 1 &&
+ git clone --bare --filter=blob:limit=0 "file://$(pwd)/server" client &&
+
+ # Ensure that there is exactly 1 negotiation by checking that there is
+ # only 1 "done" line sent. ("done" marks the end of negotiation.)
+ GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff HEAD^ HEAD &&
+ grep "git> done" trace >done_lines &&
+ test_line_count = 1 done_lines
+'
+
+test_expect_success 'diff skips same-OID blobs' '
+ rm -rf server client trace &&
+
+ test_create_repo server &&
+ echo a >server/a &&
+ echo b >server/b &&
+ git -C server add a b &&
+ git -C server commit -m x &&
+ echo another-a >server/a &&
+ git -C server add a &&
+ git -C server commit -m x &&
+
+ test_config -C server uploadpack.allowfilter 1 &&
+ test_config -C server uploadpack.allowanysha1inwant 1 &&
+ git clone --bare --filter=blob:limit=0 "file://$(pwd)/server" client &&
+
+ echo a | git hash-object --stdin >hash-old-a &&
+ echo another-a | git hash-object --stdin >hash-new-a &&
+ echo b | git hash-object --stdin >hash-b &&
+
+ # Ensure that only a and another-a are fetched.
+ GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff HEAD^ HEAD &&
+ grep "want $(cat hash-old-a)" trace &&
+ grep "want $(cat hash-new-a)" trace &&
+ ! grep "want $(cat hash-b)" trace
+'
+
+test_done
--
2.21.0.155.ge902e9bcae.dirty
