Merge branch 'pb/ort-make-submodule-conflict-message-an-advice'

When a merge conflicted at a submodule, merge-ort backend used to
unconditionally give a lengthy message to suggest how to resolve
it.  Now the message can be squelched as an advice message.

* pb/ort-make-submodule-conflict-message-an-advice:
  merge-ort: turn submodule conflict suggestions into an advice

Documentation/config/advice.txt

@@ -129,6 +129,9 @@ advice.*::
 	submoduleAlternateErrorStrategyDie::
 		Advice shown when a submodule.alternateErrorStrategy option
 		configured to "die" causes a fatal error.
+	submoduleMergeConflict::
+		Advice shown when a non-trivial submodule merge conflict is
+		encountered.
 	submodulesNotUpdated::
 		Advice shown when a user runs a submodule command that fails
 		because `git submodule update --init` was not run.

advice.c

@@ -79,6 +79,7 @@ static struct {
 	[ADVICE_STATUS_U_OPTION]			= { "statusUoption" },
 	[ADVICE_SUBMODULES_NOT_UPDATED] 		= { "submodulesNotUpdated" },
 	[ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE] = { "submoduleAlternateErrorStrategyDie" },
+	[ADVICE_SUBMODULE_MERGE_CONFLICT]               = { "submoduleMergeConflict" },
 	[ADVICE_SUGGEST_DETACHING_HEAD]			= { "suggestDetachingHead" },
 	[ADVICE_UPDATE_SPARSE_PATH]			= { "updateSparsePath" },
 	[ADVICE_WAITING_FOR_EDITOR]			= { "waitingForEditor" },

advice.h

@@ -47,6 +47,7 @@ enum advice_type {
 	ADVICE_STATUS_U_OPTION,
 	ADVICE_SUBMODULES_NOT_UPDATED,
 	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
+	ADVICE_SUBMODULE_MERGE_CONFLICT,
 	ADVICE_SUGGEST_DETACHING_HEAD,
 	ADVICE_UPDATE_SPARSE_PATH,
 	ADVICE_WAITING_FOR_EDITOR,

merge-ort.c

@@ -18,6 +18,7 @@
 #include "merge-ort.h"
 
 #include "alloc.h"
+#include "advice.h"
 #include "attr.h"
 #include "cache-tree.h"
 #include "commit.h"
@@ -4556,7 +4557,7 @@ static void print_submodule_conflict_suggestion(struct string_list *csub) {
 		      " - commit the resulting index in the superproject\n"),
 		    tmp.buf, subs.buf);
 
-	printf("%s", msg.buf);
+	advise_if_enabled(ADVICE_SUBMODULE_MERGE_CONFLICT, "%s", msg.buf);
 
 	strbuf_release(&subs);
 	strbuf_release(&tmp);

t/t6437-submodule-merge.sh

@@ -113,7 +113,7 @@ test_expect_success 'merging should conflict for non fast-forward' '
 	 git checkout -b test-nonforward-a b &&
 	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	  then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c 2>actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
 		grep "$sub_expect" actual
 	  else
@@ -154,9 +154,9 @@ test_expect_success 'merging should conflict for non fast-forward (resolution ex
 	  git rev-parse --short sub-d > ../expect) &&
 	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	  then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c >actual 2>sub-actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-		grep "$sub_expect" actual
+		grep "$sub_expect" sub-actual
 	  else
 		test_must_fail git merge c 2> actual
 	  fi &&
@@ -181,9 +181,9 @@ test_expect_success 'merging should fail for ambiguous common parent' '
 	 ) &&
 	 if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	 then
-		test_must_fail git merge c >actual &&
+		test_must_fail git merge c >actual 2>sub-actual &&
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
-		grep "$sub_expect" actual
+		grep "$sub_expect" sub-actual
 	 else
 		test_must_fail git merge c 2> actual
 	 fi &&
@@ -227,7 +227,7 @@ test_expect_success 'merging should fail for changes that are backwards' '
 	git commit -a -m "f" &&
 
 	git checkout -b test-backward e &&
-	test_must_fail git merge f >actual &&
+	test_must_fail git merge f 2>actual &&
 	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
     then
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-d)" &&
@@ -535,7 +535,7 @@ test_expect_success 'merging should fail with no merge base' '
 	git checkout -b b init &&
 	git add sub &&
 	git commit -m "b" &&
-	test_must_fail git merge a >actual &&
+	test_must_fail git merge a 2>actual &&
 	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
     then
 		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short HEAD^1)" &&

t/t7402-submodule-rebase.sh

@@ -116,7 +116,7 @@ test_expect_success 'rebasing submodule that should conflict' '
 	test_tick &&
 	git commit -m fourth &&
 
-	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 >actual_output &&
+	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 2>actual_output &&
 	git ls-files -s submodule >actual &&
 	(
 		cd submodule &&