read-tree -m -u: do not overwrite or remove untracked working tree files.

When a merge results in a creation of a path that did not exist
in HEAD, and if you already have that path on the working tree,
because the index has not been told about the working tree file,
read-tree happily removes it.  The issue was brought up by Santi
Béjar on the list.

Signed-off-by: Junio C Hamano <junkio@cox.net>

4 files changed, 48 insertions, 26 deletions

diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index 4d175d8ea1..8335a63e2e 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -39,7 +39,6 @@ test_expect_success \
      echo nitfol >nitfol &&
      echo bozbar >bozbar &&
      echo rezrov >rezrov &&
-     echo yomin >yomin &&
      git-update-index --add nitfol bozbar rezrov &&
      treeH=`git-write-tree` &&
      echo treeH $treeH &&
@@ -56,7 +55,8 @@ test_expect_success \
 
 test_expect_success \
     '1, 2, 3 - no carry forward' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      git-read-tree -m -u $treeH $treeM &&
      git-ls-files --stage >1-3.out &&
      cmp M.out 1-3.out &&
@@ -66,11 +66,12 @@ test_expect_success \
      check_cache_at frotz clean &&
      check_cache_at nitfol clean'
 
-echo '+100644 X 0	yomin' >expected
-
 test_expect_success \
     '4 - carry forward local addition.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
+     echo "+100644 X 0	yomin" >expected &&
+     echo yomin >yomin &&
      git-update-index --add yomin &&
      git-read-tree -m -u $treeH $treeM &&
      git-ls-files --stage >4.out || return 1
@@ -85,7 +86,9 @@ test_expect_success \
 
 test_expect_success \
     '5 - carry forward local addition.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
+     git-read-tree -m -u $treeH &&
      echo yomin >yomin &&
      git-update-index --add yomin &&
      echo yomin yomin >yomin &&
@@ -103,7 +106,9 @@ test_expect_success \
 
 test_expect_success \
     '6 - local addition already has the same.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
+     echo frotz >frotz &&
      git-update-index --add frotz &&
      git-read-tree -m -u $treeH $treeM &&
      git-ls-files --stage >6.out &&
@@ -117,7 +122,8 @@ test_expect_success \
 
 test_expect_success \
     '7 - local addition already has the same.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo frotz >frotz &&
      git-update-index --add frotz &&
      echo frotz frotz >frotz &&
@@ -134,14 +140,16 @@ test_expect_success \
 
 test_expect_success \
     '8 - conflicting addition.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo frotz frotz >frotz &&
      git-update-index --add frotz &&
      if git-read-tree -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '9 - conflicting addition.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo frotz frotz >frotz &&
      git-update-index --add frotz &&
      echo frotz >frotz &&
@@ -149,7 +157,8 @@ test_expect_success \
 
 test_expect_success \
     '10 - path removed.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo rezrov >rezrov &&
      git-update-index --add rezrov &&
      git-read-tree -m -u $treeH $treeM &&
@@ -160,7 +169,8 @@ test_expect_success \
 
 test_expect_success \
     '11 - dirty path removed.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo rezrov >rezrov &&
      git-update-index --add rezrov &&
      echo rezrov rezrov >rezrov &&
@@ -168,14 +178,16 @@ test_expect_success \
 
 test_expect_success \
     '12 - unmatching local changes being removed.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo rezrov rezrov >rezrov &&
      git-update-index --add rezrov &&
      if git-read-tree -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '13 - unmatching local changes being removed.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo rezrov rezrov >rezrov &&
      git-update-index --add rezrov &&
      echo rezrov >rezrov &&
@@ -188,7 +200,8 @@ EOF
 
 test_expect_success \
     '14 - unchanged in two heads.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo nitfol nitfol >nitfol &&
      git-update-index --add nitfol &&
      git-read-tree -m -u $treeH $treeM &&
@@ -207,7 +220,8 @@ test_expect_success \
 
 test_expect_success \
     '15 - unchanged in two heads.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo nitfol nitfol >nitfol &&
      git-update-index --add nitfol &&
      echo nitfol nitfol nitfol >nitfol &&
@@ -227,14 +241,16 @@ test_expect_success \
 
 test_expect_success \
     '16 - conflicting local change.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo bozbar bozbar >bozbar &&
      git-update-index --add bozbar &&
      if git-read-tree -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '17 - conflicting local change.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo bozbar bozbar >bozbar &&
      git-update-index --add bozbar &&
      echo bozbar bozbar bozbar >bozbar &&
@@ -242,7 +258,8 @@ test_expect_success \
 
 test_expect_success \
     '18 - local change already having a good result.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo gnusto >bozbar &&
      git-update-index --add bozbar &&
      git-read-tree -m -u $treeH $treeM &&
@@ -254,7 +271,8 @@ test_expect_success \
 
 test_expect_success \
     '19 - local change already having a good result, further modified.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo gnusto >bozbar &&
      git-update-index --add bozbar &&
      echo gnusto gnusto >bozbar &&
@@ -273,7 +291,8 @@ test_expect_success \
 
 test_expect_success \
     '20 - no local change, use new tree.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo bozbar >bozbar &&
      git-update-index --add bozbar &&
      git-read-tree -m -u $treeH $treeM &&
@@ -285,7 +304,8 @@ test_expect_success \
 
 test_expect_success \
     '21 - no local change, dirty cache.' \
-    'rm -f .git/index &&
+    'rm -f .git/index nitfol bozbar rezrov frotz &&
+     git-read-tree --reset -u $treeH &&
      echo bozbar >bozbar &&
      git-update-index --add bozbar &&
      echo gnusto gnusto >bozbar &&
@@ -294,7 +314,7 @@ test_expect_success \
 # Also make sure we did not break DF vs DF/DF case.
 test_expect_success \
     'DF vs DF/DF case setup.' \
-    'rm -f .git/index &&
+    'rm -f .git/index
      echo DF >DF &&
      git-update-index --add DF &&
      treeDF=`git-write-tree` &&
diff --git a/t/t3500-cherry.sh b/t/t3500-cherry.sh
index b141f89de2..e83bbee074 100755
--- a/t/t3500-cherry.sh
+++ b/t/t3500-cherry.sh
@@ -30,6 +30,7 @@ test_expect_success \
      git-commit -m "Add C." &&
 
      git-checkout -f master &&
+     rm -f B C &&
 
      echo Third >> A &&
      git-update-index A &&
diff --git a/t/t4002-diff-basic.sh b/t/t4002-diff-basic.sh
index 769274aa51..56eda63fc2 100755
--- a/t/t4002-diff-basic.sh
+++ b/t/t4002-diff-basic.sh
@@ -191,7 +191,7 @@ test_expect_success \
     'rm -fr Z [A-Z][A-Z] &&
      git-read-tree $tree_A &&
      git-checkout-index -f -a &&
-     git-read-tree -m $tree_O || return 1
+     git-read-tree --reset $tree_O || return 1
      git-update-index --refresh >/dev/null ;# this can exit non-zero
      git-diff-files >.test-a &&
      cmp_diff_files_output .test-a .test-recursive-OA'
@@ -201,7 +201,7 @@ test_expect_success \
     'rm -fr Z [A-Z][A-Z] &&
      git-read-tree $tree_B &&
      git-checkout-index -f -a &&
-     git-read-tree -m $tree_O || return 1
+     git-read-tree --reset $tree_O || return 1
      git-update-index --refresh >/dev/null ;# this can exit non-zero
      git-diff-files >.test-a &&
      cmp_diff_files_output .test-a .test-recursive-OB'
@@ -211,7 +211,7 @@ test_expect_success \
     'rm -fr Z [A-Z][A-Z] &&
      git-read-tree $tree_B &&
      git-checkout-index -f -a &&
-     git-read-tree -m $tree_A || return 1
+     git-read-tree --reset $tree_A || return 1
      git-update-index --refresh >/dev/null ;# this can exit non-zero
      git-diff-files >.test-a &&
      cmp_diff_files_output .test-a .test-recursive-AB'
diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
index a2d24b5ca9..5ac25647ab 100755
--- a/t/t6022-merge-rename.sh
+++ b/t/t6022-merge-rename.sh
@@ -111,6 +111,7 @@ test_expect_success 'pull renaming branch into unrenaming one' \
 
 test_expect_success 'pull renaming branch into another renaming one' \
 '
+	rm -f B
 	git reset --hard
 	git checkout red
 	git pull . white && {