Merge branch 'jt/lazy-fetch'

Updates to on-demand fetching code in lazily cloned repositories.

* jt/lazy-fetch:
  fetch: no FETCH_HEAD display if --no-write-fetch-head
  fetch-pack: remove no_dependents code
  promisor-remote: lazy-fetch objects in subprocess
  fetch-pack: do not lazy-fetch during ref iteration
  fetch: only populate existing_refs if needed
  fetch: avoid reading submodule config until needed
  fetch: allow refspecs specified through stdin
  negotiator/noop: add noop fetch negotiator

7 files changed, 64 insertions, 17 deletions

diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index a5ebdf9ff3..584a039b85 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -183,7 +183,7 @@ test_expect_success 'missing CLI object, but promised, passes fsck' '
 '
 
 test_expect_success 'fetching of missing objects' '
-	rm -rf repo &&
+	rm -rf repo err &&
 	test_create_repo server &&
 	test_commit -C server foo &&
 	git -C server repack -a -d --write-bitmap-index &&
@@ -194,7 +194,10 @@ test_expect_success 'fetching of missing objects' '
 
 	git -C repo config core.repositoryformatversion 1 &&
 	git -C repo config extensions.partialclone "origin" &&
-	git -C repo cat-file -p "$HASH" &&
+	git -C repo cat-file -p "$HASH" 2>err &&
+
+	# Ensure that no spurious FETCH_HEAD messages are written
+	! grep FETCH_HEAD err &&
 
 	# Ensure that the .promisor file is written, and check that its
 	# associated packfile contains the object
@@ -214,7 +217,7 @@ test_expect_success 'fetching of missing objects works with ref-in-want enabled'
 	rm -rf repo/.git/objects/* &&
 	rm -f trace &&
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C repo cat-file -p "$HASH" &&
-	grep "git< fetch=.*ref-in-want" trace
+	grep "fetch< fetch=.*ref-in-want" trace
 '
 
 test_expect_success 'fetching of missing objects from another promisor remote' '
diff --git a/t/t4067-diff-partial-clone.sh b/t/t4067-diff-partial-clone.sh
index ef8e0e9cb0..804f2a82e8 100755
--- a/t/t4067-diff-partial-clone.sh
+++ b/t/t4067-diff-partial-clone.sh
@@ -20,7 +20,7 @@ test_expect_success 'git show batches blobs' '
 	# 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 &&
+	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
 
@@ -44,7 +44,7 @@ test_expect_success 'diff batches blobs' '
 	# 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 &&
+	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
 
@@ -127,7 +127,7 @@ test_expect_success 'diff with rename detection batches blobs' '
 	# only 1 "done" line sent. ("done" marks the end of negotiation.)
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff --raw -M HEAD^ HEAD >out &&
 	grep ":100644 100644.*R[0-9][0-9][0-9].*b.*c" out &&
-	grep "git> done" trace >done_lines &&
+	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
 
@@ -175,7 +175,7 @@ test_expect_success 'diff --break-rewrites fetches only if necessary, and batche
 	# 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 --break-rewrites --raw -M HEAD^ HEAD &&
-	grep "git> done" trace >done_lines &&
+	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
 
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 3d6a93343a..392201cabd 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -528,7 +528,7 @@ test_expect_success 'prefetch objects' '
 	TWO=$(git -C server rev-parse three_branch^) &&
 	git -C client fetch --filter=blob:none origin "$TWO" &&
 	GIT_TRACE_PACKET=$(pwd)/trace git -C client push origin "$TWO":refs/heads/two_branch &&
-	grep "git> done" trace >donelines &&
+	grep "fetch> done" trace >donelines &&
 	test_line_count = 1 donelines
 '
 
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 2a1abe91f0..759aec9305 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -543,16 +543,18 @@ test_expect_success 'fetch into the current branch with --update-head-ok' '
 
 '
 
-test_expect_success 'fetch --dry-run does not touch FETCH_HEAD' '
-	rm -f .git/FETCH_HEAD &&
-	git fetch --dry-run . &&
-	! test -f .git/FETCH_HEAD
+test_expect_success 'fetch --dry-run does not touch FETCH_HEAD, but still prints what would be written' '
+	rm -f .git/FETCH_HEAD err &&
+	git fetch --dry-run . 2>err &&
+	! test -f .git/FETCH_HEAD &&
+	grep FETCH_HEAD err
 '
 
-test_expect_success '--no-write-fetch-head does not touch FETCH_HEAD' '
-	rm -f .git/FETCH_HEAD &&
-	git fetch --no-write-fetch-head . &&
-	! test -f .git/FETCH_HEAD
+test_expect_success '--no-write-fetch-head does not touch FETCH_HEAD, and does not print what would be written' '
+	rm -f .git/FETCH_HEAD err &&
+	git fetch --no-write-fetch-head . 2>err &&
+	! test -f .git/FETCH_HEAD &&
+	! grep FETCH_HEAD err
 '
 
 test_expect_success '--write-fetch-head gets defeated by --dry-run' '
diff --git a/t/t5554-noop-fetch-negotiator.sh b/t/t5554-noop-fetch-negotiator.sh
new file mode 100755
index 0000000000..2ac7b5859e
--- /dev/null
+++ b/t/t5554-noop-fetch-negotiator.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+test_description='test noop fetch negotiator'
+. ./test-lib.sh
+
+test_expect_success 'noop negotiator does not emit any "have"' '
+	rm -f trace &&
+
+	test_create_repo server &&
+	test_commit -C server to_fetch &&
+
+	test_create_repo client &&
+	test_commit -C client we_have &&
+
+	test_config -C client fetch.negotiationalgorithm noop &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch "$(pwd)/server" &&
+
+	! grep "fetch> have" trace &&
+	grep "fetch> done" trace
+'
+
+test_done
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index eb9a093e25..15fb64c18d 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -704,7 +704,7 @@ test_expect_success 'batch missing blob request during checkout' '
 	# Ensure that there is only one negotiation by checking that there is
 	# only "done" line sent. ("done" marks the end of negotiation.)
 	GIT_TRACE_PACKET="$(pwd)/trace" git -C client checkout HEAD^ &&
-	grep "git> done" trace >done_lines &&
+	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
 
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 5a01466db4..f4d49d8335 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -433,6 +433,26 @@ test_expect_success 'fetch lazy-fetches only to resolve deltas, protocol v2' '
 	grep "want $(cat hash)" trace
 '
 
+test_expect_success 'fetch does not lazy-fetch missing targets of its refs' '
+	rm -rf server client trace &&
+
+	test_create_repo server &&
+	test_config -C server uploadpack.allowfilter 1 &&
+	test_config -C server uploadpack.allowanysha1inwant 1 &&
+	test_commit -C server foo &&
+
+	git clone --filter=blob:none "file://$(pwd)/server" client &&
+	# Make all refs point to nothing by deleting all objects.
+	rm client/.git/objects/pack/* &&
+
+	test_commit -C server bar &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client fetch \
+		--no-tags --recurse-submodules=no \
+		origin refs/tags/bar &&
+	FOO_HASH=$(git -C server rev-parse foo) &&
+	! grep "want $FOO_HASH" trace
+'
+
 # The following two tests must be in this order. It is important that
 # the srv.bare repository did not have tags during clone, but has tags
 # in the fetch.