Merge branch 'mh/fetch-tags-in-addition-to-normal-refs'

The "--tags" option to "git fetch" used to be literally a synonym to
a "refs/tags/*:refs/tags/*" refspec, which meant that (1) as an
explicit refspec given from the command line, it silenced the lazy
"git fetch" default that is configured, and (2) also as an explicit
refspec given from the command line, it interacted with "--prune"
to remove any tag that the remote we are fetching from does not
have.

This demotes it to an option; with it, we fetch all tags in
addition to what would be fetched without the option, and it does
not interact with the decision "--prune" makes to see what
remote-tracking refs the local has are missing the remote
counterpart.

* mh/fetch-tags-in-addition-to-normal-refs: (23 commits)
  fetch: improve the error messages emitted for conflicting refspecs
  handle_duplicate(): mark error message for translation
  ref_remote_duplicates(): extract a function handle_duplicate()
  ref_remove_duplicates(): simplify loop logic
  t5536: new test of refspec conflicts when fetching
  ref_remove_duplicates(): avoid redundant bisection
  git-fetch.txt: improve description of tag auto-following
  fetch-options.txt: simplify ifdef/ifndef/endif usage
  fetch, remote: properly convey --no-prune options to subprocesses
  builtin/remote.c:update(): use struct argv_array
  builtin/remote.c: reorder function definitions
  query_refspecs(): move some constants out of the loop
  fetch --prune: prune only based on explicit refspecs
  fetch --tags: fetch tags *in addition to* other stuff
  fetch: only opportunistically update references based on command line
  get_expanded_map(): avoid memory leak
  get_expanded_map(): add docstring
  builtin/fetch.c: reorder function definitions
  get_ref_map(): rename local variables
  api-remote.txt: correct section "struct refspec"
  ...

5 files changed, 148 insertions, 13 deletions

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 1f0f8e6827..5d4581dac8 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -88,7 +88,7 @@ test_expect_success 'fetch --prune on its own works as expected' '
 	cd "$D" &&
 	git clone . prune &&
 	cd prune &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune origin &&
 	test_must_fail git rev-parse origin/extrabranch
@@ -98,7 +98,7 @@ test_expect_success 'fetch --prune with a branch name keeps branches' '
 	cd "$D" &&
 	git clone . prune-branch &&
 	cd prune-branch &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune origin master &&
 	git rev-parse origin/extrabranch
@@ -113,25 +113,45 @@ test_expect_success 'fetch --prune with a namespace keeps other namespaces' '
 	git rev-parse origin/master
 '
 
-test_expect_success 'fetch --prune --tags does not delete the remote-tracking branches' '
+test_expect_success 'fetch --prune --tags prunes branches but not tags' '
 	cd "$D" &&
 	git clone . prune-tags &&
 	cd prune-tags &&
-	git fetch origin refs/heads/master:refs/tags/sometag &&
+	git tag sometag master &&
+	# Create what looks like a remote-tracking branch from an earlier
+	# fetch that has since been deleted from the remote:
+	git update-ref refs/remotes/origin/fake-remote master &&
 
 	git fetch --prune --tags origin &&
 	git rev-parse origin/master &&
-	test_must_fail git rev-parse somebranch
+	test_must_fail git rev-parse origin/fake-remote &&
+	git rev-parse sometag
 '
 
-test_expect_success 'fetch --prune --tags with branch does not delete other remote-tracking branches' '
+test_expect_success 'fetch --prune --tags with branch does not prune other things' '
 	cd "$D" &&
 	git clone . prune-tags-branch &&
 	cd prune-tags-branch &&
-	git fetch origin refs/heads/master:refs/remotes/origin/extrabranch &&
+	git tag sometag master &&
+	git update-ref refs/remotes/origin/extrabranch master &&
 
 	git fetch --prune --tags origin master &&
-	git rev-parse origin/extrabranch
+	git rev-parse origin/extrabranch &&
+	git rev-parse sometag
+'
+
+test_expect_success 'fetch --prune --tags with refspec prunes based on refspec' '
+	cd "$D" &&
+	git clone . prune-tags-refspec &&
+	cd prune-tags-refspec &&
+	git tag sometag master &&
+	git update-ref refs/remotes/origin/foo/otherbranch master &&
+	git update-ref refs/remotes/origin/extrabranch master &&
+
+	git fetch --prune --tags origin refs/heads/foo/*:refs/remotes/origin/foo/* &&
+	test_must_fail git rev-parse refs/remotes/origin/foo/otherbranch &&
+	git rev-parse origin/extrabranch &&
+	git rev-parse sometag
 '
 
 test_expect_success 'fetch tags when there is no tags' '
diff --git a/t/t5515/fetch.br-unconfig_--tags_.._.git b/t/t5515/fetch.br-unconfig_--tags_.._.git
index 1669cc4af0..0f70f66c70 100644
--- a/t/t5515/fetch.br-unconfig_--tags_.._.git
+++ b/t/t5515/fetch.br-unconfig_--tags_.._.git
@@ -1,4 +1,5 @@
 # br-unconfig --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5515/fetch.master_--tags_.._.git b/t/t5515/fetch.master_--tags_.._.git
index 8a7493537b..ab473a6e1f 100644
--- a/t/t5515/fetch.master_--tags_.._.git
+++ b/t/t5515/fetch.master_--tags_.._.git
@@ -1,4 +1,5 @@
 # master --tags ../.git
+0567da4d5edd2ff4bb292a465ba9e64dcad9536b		../
 6c9dec2b923228c9ff994c6cfe4ae16c12408dc5	not-for-merge	tag 'tag-master' of ../
 8e32a6d901327a23ef831511badce7bf3bf46689	not-for-merge	tag 'tag-one' of ../
 22feea448b023a2d864ef94b013735af34d238ba	not-for-merge	tag 'tag-one-tree' of ../
diff --git a/t/t5525-fetch-tagopt.sh b/t/t5525-fetch-tagopt.sh
index 4fbf7a120f..45815f7378 100755
--- a/t/t5525-fetch-tagopt.sh
+++ b/t/t5525-fetch-tagopt.sh
@@ -8,7 +8,8 @@ setup_clone () {
 	git clone --mirror . $1 &&
 	git remote add remote_$1 $1 &&
 	(cd $1 &&
-	git tag tag_$1)
+	git tag tag_$1 &&
+	git branch branch_$1)
 }
 
 test_expect_success setup '
@@ -21,21 +22,33 @@ test_expect_success setup '
 
 test_expect_success "fetch with tagopt=--no-tags does not get tag" '
 	git fetch remote_one &&
-	test_must_fail git show-ref tag_one
+	test_must_fail git show-ref tag_one &&
+	git show-ref remote_one/branch_one
 	'
 
 test_expect_success "fetch --tags with tagopt=--no-tags gets tag" '
+	(
+		cd one &&
+		git branch second_branch_one
+	) &&
 	git fetch --tags remote_one &&
-	git show-ref tag_one
+	git show-ref tag_one &&
+	git show-ref remote_one/second_branch_one
 	'
 
 test_expect_success "fetch --no-tags with tagopt=--tags does not get tag" '
 	git fetch --no-tags remote_two &&
-	test_must_fail git show-ref tag_two
+	test_must_fail git show-ref tag_two &&
+	git show-ref remote_two/branch_two
 	'
 
 test_expect_success "fetch with tagopt=--tags gets tag" '
+	(
+		cd two &&
+		git branch second_branch_two
+	) &&
 	git fetch remote_two &&
-	git show-ref tag_two
+	git show-ref tag_two &&
+	git show-ref remote_two/second_branch_two
 	'
 test_done
diff --git a/t/t5536-fetch-conflicts.sh b/t/t5536-fetch-conflicts.sh
new file mode 100755
index 0000000000..6c5d3a4ce0
--- /dev/null
+++ b/t/t5536-fetch-conflicts.sh
@@ -0,0 +1,100 @@
+#!/bin/sh
+
+test_description='fetch handles conflicting refspecs correctly'
+
+. ./test-lib.sh
+
+D=$(pwd)
+
+setup_repository () {
+	git init "$1" && (
+		cd "$1" &&
+		git config remote.origin.url "$D" &&
+		shift &&
+		for refspec in "$@"
+		do
+			git config --add remote.origin.fetch "$refspec"
+		done
+	)
+}
+
+verify_stderr () {
+	cat >expected &&
+	# We're not interested in the error
+	# "fatal: The remote end hung up unexpectedly":
+	grep -E '^(fatal|warning):' <error | grep -v 'hung up' >actual | sort &&
+	test_cmp expected actual
+}
+
+test_expect_success 'setup' '
+	git commit --allow-empty -m "Initial" &&
+	git branch branch1 &&
+	git tag tag1 &&
+	git commit --allow-empty -m "First" &&
+	git branch branch2 &&
+	git tag tag2
+'
+
+test_expect_success 'fetch with no conflict' '
+	setup_repository ok "+refs/heads/*:refs/remotes/origin/*" && (
+		cd ok &&
+		git fetch origin
+	)
+'
+
+test_expect_success 'fetch conflict: config vs. config' '
+	setup_repository ccc \
+		"+refs/heads/branch1:refs/remotes/origin/branch1" \
+		"+refs/heads/branch2:refs/remotes/origin/branch1" && (
+		cd ccc &&
+		test_must_fail git fetch origin 2>error &&
+		verify_stderr <<-\EOF
+		fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
+		EOF
+	)
+'
+
+test_expect_success 'fetch duplicate: config vs. config' '
+	setup_repository dcc \
+		"+refs/heads/*:refs/remotes/origin/*" \
+		"+refs/heads/branch1:refs/remotes/origin/branch1" && (
+		cd dcc &&
+		git fetch origin
+	)
+'
+
+test_expect_success 'fetch conflict: arg overrides config' '
+	setup_repository aoc \
+		"+refs/heads/*:refs/remotes/origin/*" && (
+		cd aoc &&
+		git fetch origin refs/heads/branch2:refs/remotes/origin/branch1
+	)
+'
+
+test_expect_success 'fetch conflict: arg vs. arg' '
+	setup_repository caa && (
+		cd caa &&
+		test_must_fail git fetch origin \
+			refs/heads/*:refs/remotes/origin/* \
+			refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
+		verify_stderr <<-\EOF
+		fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
+		EOF
+	)
+'
+
+test_expect_success 'fetch conflict: criss-cross args' '
+	setup_repository xaa \
+		"+refs/heads/*:refs/remotes/origin/*" && (
+		cd xaa &&
+		git fetch origin \
+			refs/heads/branch1:refs/remotes/origin/branch2 \
+			refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
+		verify_stderr <<-\EOF
+		warning: refs/remotes/origin/branch1 usually tracks refs/heads/branch1, not refs/heads/branch2
+		warning: refs/remotes/origin/branch2 usually tracks refs/heads/branch2, not refs/heads/branch1
+		EOF
+	)
+'
+
+test_done