Teach read-tree the -n|--dry-run option

The option can be used to check if read-tree with the same set of other
options like "-m" and "-u" would succeed without actually changing either
the index or the working tree.

The relevant tests in the t10?? range were extended to do a read-tree -n
before the real read-tree to make sure neither the index nor any local
files were changed with -n and the same exit code as without -n is
returned. The helper functions added for that purpose reside in the new
t/lib-read-tree.sh file.

The only exception is #13 in t1004 ("unlinking an un-unlink-able
symlink"). As this is an issue of wrong directory permissions it is not
detected with -n.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 41 insertions, 40 deletions

diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index a4a17e0017..a847709a13 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -9,6 +9,7 @@ This is identical to t1001, but uses -u to update the work tree as well.
 
 '
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-read-tree.sh
 
 compare_change () {
 	sed >current \
@@ -56,8 +57,8 @@ test_expect_success \
 test_expect_success \
     '1, 2, 3 - no carry forward' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed --reset -u $treeH &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >1-3.out &&
      cmp M.out 1-3.out &&
      sum bozbar frotz nitfol >actual3.sum &&
@@ -69,11 +70,11 @@ test_expect_success \
 test_expect_success \
     '4 - carry forward local addition.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo "+100644 X 0	yomin" >expected &&
      echo yomin >yomin &&
      git update-index --add yomin &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >4.out || return 1
      git diff -U0 --no-index M.out 4.out >4diff.out
      compare_change 4diff.out expected &&
@@ -87,12 +88,12 @@ test_expect_success \
 test_expect_success \
     '5 - carry forward local addition.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
-     git read-tree -m -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
+     read_tree_u_must_succeed -m -u $treeH &&
      echo yomin >yomin &&
      git update-index --add yomin &&
      echo yomin yomin >yomin &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >5.out || return 1
      git diff -U0 --no-index M.out 5.out >5diff.out
      compare_change 5diff.out expected &&
@@ -107,10 +108,10 @@ test_expect_success \
 test_expect_success \
     '6 - local addition already has the same.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo frotz >frotz &&
      git update-index --add frotz &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >6.out &&
      test_cmp M.out 6.out &&
      check_cache_at frotz clean &&
@@ -123,11 +124,11 @@ test_expect_success \
 test_expect_success \
     '7 - local addition already has the same.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo frotz >frotz &&
      git update-index --add frotz &&
      echo frotz frotz >frotz &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >7.out &&
      test_cmp M.out 7.out &&
      check_cache_at frotz dirty &&
@@ -141,27 +142,27 @@ test_expect_success \
 test_expect_success \
     '8 - conflicting addition.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo frotz frotz >frotz &&
      git update-index --add frotz &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '9 - conflicting addition.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo frotz frotz >frotz &&
      git update-index --add frotz &&
      echo frotz >frotz &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '10 - path removed.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo rezrov >rezrov &&
      git update-index --add rezrov &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >10.out &&
      cmp M.out 10.out &&
      sum bozbar frotz nitfol >actual10.sum &&
@@ -170,28 +171,28 @@ test_expect_success \
 test_expect_success \
     '11 - dirty path removed.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo rezrov >rezrov &&
      git update-index --add rezrov &&
      echo rezrov rezrov >rezrov &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '12 - unmatching local changes being removed.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo rezrov rezrov >rezrov &&
      git update-index --add rezrov &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '13 - unmatching local changes being removed.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo rezrov rezrov >rezrov &&
      git update-index --add rezrov &&
      echo rezrov >rezrov &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 cat >expected <<EOF
 -100644 X 0	nitfol
@@ -201,10 +202,10 @@ EOF
 test_expect_success \
     '14 - unchanged in two heads.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo nitfol nitfol >nitfol &&
      git update-index --add nitfol &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >14.out &&
      test_must_fail git diff -U0 --no-index M.out 14.out >14diff.out &&
      compare_change 14diff.out expected &&
@@ -221,11 +222,11 @@ test_expect_success \
 test_expect_success \
     '15 - unchanged in two heads.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo nitfol nitfol >nitfol &&
      git update-index --add nitfol &&
      echo nitfol nitfol nitfol >nitfol &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >15.out &&
      test_must_fail git diff -U0 --no-index M.out 15.out >15diff.out &&
      compare_change 15diff.out expected &&
@@ -242,27 +243,27 @@ test_expect_success \
 test_expect_success \
     '16 - conflicting local change.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo bozbar bozbar >bozbar &&
      git update-index --add bozbar &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '17 - conflicting local change.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo bozbar bozbar >bozbar &&
      git update-index --add bozbar &&
      echo bozbar bozbar bozbar >bozbar &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 test_expect_success \
     '18 - local change already having a good result.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo gnusto >bozbar &&
      git update-index --add bozbar &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >18.out &&
      test_cmp M.out 18.out &&
      check_cache_at bozbar clean &&
@@ -272,11 +273,11 @@ test_expect_success \
 test_expect_success \
     '19 - local change already having a good result, further modified.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo gnusto >bozbar &&
      git update-index --add bozbar &&
      echo gnusto gnusto >bozbar &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >19.out &&
      test_cmp M.out 19.out &&
      check_cache_at bozbar dirty &&
@@ -292,10 +293,10 @@ test_expect_success \
 test_expect_success \
     '20 - no local change, use new tree.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo bozbar >bozbar &&
      git update-index --add bozbar &&
-     git read-tree -m -u $treeH $treeM &&
+     read_tree_u_must_succeed -m -u $treeH $treeM &&
      git ls-files --stage >20.out &&
      test_cmp M.out 20.out &&
      check_cache_at bozbar clean &&
@@ -305,11 +306,11 @@ test_expect_success \
 test_expect_success \
     '21 - no local change, dirty cache.' \
     'rm -f .git/index nitfol bozbar rezrov frotz &&
-     git read-tree --reset -u $treeH &&
+     read_tree_u_must_succeed --reset -u $treeH &&
      echo bozbar >bozbar &&
      git update-index --add bozbar &&
      echo gnusto gnusto >bozbar &&
-     if git read-tree -m -u $treeH $treeM; then false; else :; fi'
+     if read_tree_u_must_succeed -m -u $treeH $treeM; then false; else :; fi'
 
 # Also make sure we did not break DF vs DF/DF case.
 test_expect_success \
@@ -336,7 +337,7 @@ test_expect_success \
      rm -fr DF &&
      echo DF >DF &&
      git update-index --add DF &&
-     git read-tree -m -u $treeDF $treeDFDF &&
+     read_tree_u_must_succeed -m -u $treeDF $treeDFDF &&
      git ls-files --stage >DFDFcheck.out &&
      test_cmp DFDF.out DFDFcheck.out &&
      check_cache_at DF/DF clean'