Merge branch 'jk/utf8-switch-between-nfd-and-nfc'

Document a known breakage with a test.

* jk/utf8-switch-between-nfd-and-nfc:
t3910: show failure of core.precomposeunicode with decomposed filenames

diff --combined t/t3910-mac-os-precompose.sh
index 96941e94cc3b50d0f65a441316e577dee2adc7e2,23aa61ef0904457ab97a5d132218464905783a7c..831935665e012c04bbe4c57feee92c0310df5c04
--- 1/t/t3910-mac-os-precompose.sh
--- 2/t/t3910-mac-os-precompose.sh
+++ b/t/t3910-mac-os-precompose.sh
@@@ -14,13 -14,13 +14,13 @@@ the
  fi
  
  # create utf-8 variables
 -Adiarnfc=`printf '\303\204'`
 -Adiarnfd=`printf 'A\314\210'`
 +Adiarnfc=$(printf '\303\204')
 +Adiarnfd=$(printf 'A\314\210')
  
 -Odiarnfc=`printf '\303\226'`
 -Odiarnfd=`printf 'O\314\210'`
 -AEligatu=`printf '\303\206'`
 -Invalidu=`printf '\303\377'`
 +Odiarnfc=$(printf '\303\226')
 +Odiarnfd=$(printf 'O\314\210')
 +AEligatu=$(printf '\303\206')
 +Invalidu=$(printf '\303\377')
  
  
  #Create a string with 255 bytes (decomposed)
@@@ -35,7 -35,7 +35,7 @@@ Alongc=$Alongc$Alongc$Alongc$Alongc$Alo
  Alongc=$Alongc$AEligatu$AEligatu                     #254 Byte
  
  test_expect_success "detect if nfd needed" '
 -      precomposeunicode=`git config core.precomposeunicode` &&
 +      precomposeunicode=$(git config core.precomposeunicode) &&
        test "$precomposeunicode" = true &&
        git config core.precomposeunicode true
  '
@@@ -140,13 -140,23 +140,23 @@@ test_expect_success "Add long precompos
        git add * &&
        git commit -m "Long filename"
  '
+ 
+ test_expect_failure 'handle existing decomposed filenames' '
+       echo content >"verbatim.$Adiarnfd" &&
+       git -c core.precomposeunicode=false add "verbatim.$Adiarnfd" &&
+       git commit -m "existing decomposed file" &&
+       >expect &&
+       git ls-files --exclude-standard -o "verbatim*" >untracked &&
+       test_cmp expect untracked
+ '
+ 
  # Test if the global core.precomposeunicode stops autosensing
  # Must be the last test case
  test_expect_success "respect git config --global core.precomposeunicode" '
        git config --global core.precomposeunicode true &&
        rm -rf .git &&
        git init &&
 -      precomposeunicode=`git config core.precomposeunicode` &&
 +      precomposeunicode=$(git config core.precomposeunicode) &&
        test "$precomposeunicode" = "true"
  '