Subject: [PATCH] mergetool: Provide an empty file when no base exists

From: David Aguilar <[email-masked]>
Date: Thu, 19 Jan 2012 23:10:53 -0800

Some mergetools cannot cope when $BASE is missing.
This can happen when two branches add the same file.
Provide an empty file to make these tools happy.

Reported-by: Jason Wenger <[email-masked]>
Signed-off-by: David Aguilar <[email-masked]>
---
 git-mergetool.sh     |    6 +++++-
 t/t7610-mergetool.sh |   27 ++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 085e213..0131559 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -224,7 +224,11 @@ merge_file () {
     mv -- "$MERGED" "$BACKUP"
     cp -- "$BACKUP" "$MERGED"
 
-    base_present   && checkout_staged_file 1 "$MERGED" "$BASE"
+    if base_present; then
+	checkout_staged_file 1 "$MERGED" "$BASE"
+    else
+	:>"$BASE"
+    fi
     local_present  && checkout_staged_file 2 "$MERGED" "$LOCAL"
     remote_present && checkout_staged_file 3 "$MERGED" "$REMOTE"
 
diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 4aab2a7..2272743 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -39,6 +39,7 @@ test_expect_success 'setup' '
     echo branch1 change >file1 &&
     echo branch1 newfile >file2 &&
     echo branch1 spaced >"spaced name" &&
+    echo branch1 both added > both &&
     echo branch1 change file11 >file11 &&
     echo branch1 change file13 >file13 &&
     echo branch1 sub >subdir/file3 &&
@@ -50,6 +51,7 @@ test_expect_success 'setup' '
 	git checkout -b submod-branch1
     ) &&
     git add file1 "spaced name" file11 file13 file2 subdir/file3 submod &&
+    git add both &&
     git rm file12 &&
     git commit -m "branch1 changes" &&
 
@@ -58,6 +60,7 @@ test_expect_success 'setup' '
     echo master updated >file1 &&
     echo master new >file2 &&
     echo master updated spaced >"spaced name" &&
+    echo master both added > both &&
     echo master updated file12 >file12 &&
     echo master updated file14 >file14 &&
     echo master new sub >subdir/file3 &&
@@ -69,18 +72,22 @@ test_expect_success 'setup' '
 	git checkout -b submod-master
     ) &&
     git add file1 "spaced name" file12 file14 file2 subdir/file3 submod &&
+    git add both &&
     git rm file11 &&
     git commit -m "master updates" &&
 
     git config merge.tool mytool &&
     git config mergetool.mytool.cmd "cat \"\$REMOTE\" >\"\$MERGED\"" &&
-    git config mergetool.mytool.trustExitCode true
+    git config mergetool.mytool.trustExitCode true &&
+    git config mergetool.mybase.cmd "cat \"\$BASE\" >\"\$MERGED\"" &&
+    git config mergetool.mybase.trustExitCode true
 '
 
 test_expect_success 'custom mergetool' '
     git checkout -b test1 branch1 &&
     git submodule update -N &&
     test_must_fail git merge master >/dev/null 2>&1 &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "" | git mergetool file1 file1 ) &&
     ( yes "" | git mergetool file2 "spaced name" >/dev/null 2>&1 ) &&
     ( yes "" | git mergetool subdir/file3 >/dev/null 2>&1 ) &&
@@ -101,6 +108,7 @@ test_expect_success 'mergetool crlf' '
     ( yes "" | git mergetool file1 >/dev/null 2>&1 ) &&
     ( yes "" | git mergetool file2 >/dev/null 2>&1 ) &&
     ( yes "" | git mergetool "spaced name" >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "" | git mergetool subdir/file3 >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file12 >/dev/null 2>&1 ) &&
@@ -131,6 +139,7 @@ test_expect_success 'mergetool on file in parent dir' '
 	cd subdir &&
 	( yes "" | git mergetool ../file1 >/dev/null 2>&1 ) &&
 	( yes "" | git mergetool ../file2 ../spaced\ name >/dev/null 2>&1 ) &&
+	( yes "" | git mergetool ../both >/dev/null 2>&1 ) &&
 	( yes "d" | git mergetool ../file11 >/dev/null 2>&1 ) &&
 	( yes "d" | git mergetool ../file12 >/dev/null 2>&1 ) &&
 	( yes "l" | git mergetool ../submod >/dev/null 2>&1 ) &&
@@ -212,6 +221,7 @@ test_expect_success 'deleted vs modified submodule' '
     test_must_fail git merge master &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "r" | git mergetool submod ) &&
     rmdir submod && mv submod-movedaside submod &&
@@ -228,6 +238,7 @@ test_expect_success 'deleted vs modified submodule' '
     test_must_fail git merge master &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "l" | git mergetool submod ) &&
     test ! -e submod &&
@@ -241,6 +252,7 @@ test_expect_success 'deleted vs modified submodule' '
     test_must_fail git merge test6 &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "r" | git mergetool submod ) &&
     test ! -e submod &&
@@ -256,6 +268,7 @@ test_expect_success 'deleted vs modified submodule' '
     test_must_fail git merge test6 &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "l" | git mergetool submod ) &&
     test "$(cat submod/bar)" = "master submodule" &&
@@ -279,6 +292,7 @@ test_expect_success 'file vs modified submodule' '
     test_must_fail git merge master &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "r" | git mergetool submod ) &&
     rmdir submod && mv submod-movedaside submod &&
@@ -294,6 +308,7 @@ test_expect_success 'file vs modified submodule' '
     test_must_fail git merge master &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "l" | git mergetool submod ) &&
     git submodule update -N &&
@@ -309,6 +324,7 @@ test_expect_success 'file vs modified submodule' '
     test_must_fail git merge test7 &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both >/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "r" | git mergetool submod ) &&
     test -d submod.orig &&
@@ -324,6 +340,7 @@ test_expect_success 'file vs modified submodule' '
     test_must_fail git merge test7 &&
     test -n "$(git ls-files -u)" &&
     ( yes "" | git mergetool file1 file2 spaced\ name subdir/file3 >/dev/null 2>&1 ) &&
+    ( yes "" | git mergetool both>/dev/null 2>&1 ) &&
     ( yes "d" | git mergetool file11 file12 >/dev/null 2>&1 ) &&
     ( yes "l" | git mergetool submod ) &&
     test "$(cat submod/bar)" = "master submodule" &&
@@ -445,4 +462,12 @@ test_expect_success 'directory vs modified submodule' '
     git submodule update -N
 '
 
+test_expect_success 'file with no base' '
+    git checkout -b test13 branch1 &&
+    test_must_fail git merge master &&
+    git mergetool --no-prompt --tool mybase -- base &&
+    test "$(cat "$MERGED")" = "" &&
+    git reset --hard master >/dev/null 2>&1
+'
+
 test_done
-- 
1.7.9.rc2.1.gdcba7