Re: [PATCH v2 2/2] diff: batch fetching of missing blobs

[Christian Couder <christian.couder@gmail.com>]

Hi,

On Fri, Apr 5, 2019 at 3:38 PM Johannes Schindelin
<Johannes.Schindelin@gmx.de> wrote:

> On Thu, 4 Apr 2019, SZEDER Gábor wrote:
>
> > On Fri, Mar 29, 2019 at 02:39:28PM -0700, Jonathan Tan wrote:
> > > diff --git a/t/t4067-diff-partial-clone.sh b/t/t4067-diff-partial-clone.sh
> > > new file mode 100755
> > > index 0000000000..349851be7d
> > > --- /dev/null
> > > +++ b/t/t4067-diff-partial-clone.sh
> > > @@ -0,0 +1,103 @@
> > > +#!/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_when_finished "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 &&
> > > +
> > > +   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
> >
> > These patches and 'cc/multi-promisor' don't seem to work well
> > together, and all tests checking 'test_line_count = 1 done_lines' in
> > this test script fail in current 'pu', because there are two
> > "git> done" lines.
>
> I investigated a little further, and it would seem that it is neither this
> patch nor the cc/multi-promisor patches that introduce the problem, but
> the merge between the two... The latter tries to get away from using the
> global variable `repository_format_partial_clone` while this patch
> introduces another user.

Thanks for investigating! Yeah, that's part of the problem.

The fix I would suggest is:

diff --git a/diff.c b/diff.c
index f685ab10b5..a2b1241f83 100644
--- a/diff.c
+++ b/diff.c
@@ -26,6 +26,7 @@
 #include "parse-options.h"
 #include "help.h"
 #include "fetch-object.h"
+#include "promisor-remote.h"

 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -6489,7 +6490,7 @@ static void add_if_missing(struct oid_array *to_fetch,

 void diffcore_std(struct diff_options *options)
 {
-    if (repository_format_partial_clone) {
+    if (has_promisor_remote()) {
         /*
          * Prefetch the diff pairs that are about to be flushed.
          */
@@ -6506,8 +6507,7 @@ void diffcore_std(struct diff_options *options)
             /*
              * NEEDSWORK: Consider deduplicating the OIDs sent.
              */
-            fetch_objects(repository_format_partial_clone,
-                      to_fetch.oid, to_fetch.nr);
+            promisor_remote_get_direct(to_fetch.oid, to_fetch.nr);
         oid_array_clear(&to_fetch);
     }

I will send a new version with the above soon based on top of
jt/batch-fetch-blobs-in-diff in pu.