Use prerequisite tags to skip tests that depend on symbolic links

Many tests depend on that symbolic links work.  This introduces a check
that sets the prerequisite tag SYMLINKS if the file system supports
symbolic links.  Since so many tests have to check for this prerequisite,
we do the check in test-lib.sh, so that we don't need to repeat the test
in many scripts.

To check for 'ln -s' failures, you can use a FAT partition on Linux:

$ mkdosfs -C git-on-fat 1000000
$ sudo mount -o loop,uid=j6t,gid=users,shortname=winnt git-on-fat /mnt

Clone git to /mnt and

$ GIT_SKIP_TESTS='t0001.1[34] t0010 t1301 t403[34] t4129.[47] t5701.7
          t7701.3 t9100 t9101.26 t9119 t9124.[67] t9200.10 t9600.6' \
        make test

(These additionally skipped tests depend on POSIX permissions that FAT on
Linux does not provide.)

Signed-off-by: Johannes Sixt <j6t@kdbg.org>

t/t0000-basic.sh

@@ -115,12 +115,31 @@ test_expect_success \
     'test "$tree" = 4b825dc642cb6eb9a060e54bf8d69288fbee4904'
 
 # Various types of objects
+# Some filesystems do not support symblic links; on such systems
+# some expected values are different
 mkdir path2 path3 path3/subp3
-for p in path0 path2/file2 path3/file3 path3/subp3/file3
+paths='path0 path2/file2 path3/file3 path3/subp3/file3'
+for p in $paths
 do
     echo "hello $p" >$p
-    ln -s "hello $p" ${p}sym
 done
+if test_have_prereq SYMLINKS
+then
+	for p in $paths
+	do
+		ln -s "hello $p" ${p}sym
+	done
+	expectfilter=cat
+	expectedtree=087704a96baf1c2d1c869a8b084481e121c88b5b
+	expectedptree1=21ae8269cacbe57ae09138dcc3a2887f904d02b3
+	expectedptree2=3c5e5399f3a333eddecce7a9b9465b63f65f51e2
+else
+	expectfilter='grep -v sym'
+	expectedtree=8e18edf7d7edcf4371a3ac6ae5f07c2641db7c46
+	expectedptree1=cfb8591b2f65de8b8cc1020cd7d9e67e7793b325
+	expectedptree2=ce580448f0148b985a513b693fdf7d802cacb44f
+fi
+
 test_expect_success \
     'adding various types of objects with git update-index --add.' \
     'find path* ! -type d -print | xargs git update-index --add'
@@ -130,7 +149,7 @@ test_expect_success \
     'showing stage with git ls-files --stage' \
     'git ls-files --stage >current'
 
-cat >expected <<\EOF
+$expectfilter >expected <<\EOF
 100644 f87290f8eb2cbbea7857214459a0739927eab154 0	path0
 120000 15a98433ae33114b085f3eb3bb03b832b3180a01 0	path0sym
 100644 3feff949ed00a62d9f7af97c15cd8a30595e7ac7 0	path2/file2
@@ -149,7 +168,7 @@ test_expect_success \
     'tree=$(git write-tree)'
 test_expect_success \
     'validate object ID for a known tree.' \
-    'test "$tree" = 087704a96baf1c2d1c869a8b084481e121c88b5b'
+    'test "$tree" = "$expectedtree"'
 
 test_expect_success \
     'showing tree with git ls-tree' \
@@ -160,7 +179,7 @@ cat >expected <<\EOF
 040000 tree 58a09c23e2ca152193f2786e06986b7b6712bdbe	path2
 040000 tree 21ae8269cacbe57ae09138dcc3a2887f904d02b3	path3
 EOF
-test_expect_success \
+test_expect_success SYMLINKS \
     'git ls-tree output for a known tree.' \
     'test_cmp expected current'
 
@@ -169,7 +188,7 @@ test_expect_success \
 test_expect_success \
     'showing tree with git ls-tree -r' \
     'git ls-tree -r $tree >current'
-cat >expected <<\EOF
+$expectfilter >expected <<\EOF
 100644 blob f87290f8eb2cbbea7857214459a0739927eab154	path0
 120000 blob 15a98433ae33114b085f3eb3bb03b832b3180a01	path0sym
 100644 blob 3feff949ed00a62d9f7af97c15cd8a30595e7ac7	path2/file2
@@ -200,7 +219,7 @@ cat >expected <<\EOF
 100644 blob 00fb5908cb97c2564a9783c0c64087333b3b464f	path3/subp3/file3
 120000 blob 6649a1ebe9e9f1c553b66f5a6e74136a07ccc57c	path3/subp3/file3sym
 EOF
-test_expect_success \
+test_expect_success SYMLINKS \
     'git ls-tree -r output for a known tree.' \
     'test_cmp expected current'
 
@@ -209,14 +228,14 @@ test_expect_success \
     'ptree=$(git write-tree --prefix=path3)'
 test_expect_success \
     'validate object ID for a known tree.' \
-    'test "$ptree" = 21ae8269cacbe57ae09138dcc3a2887f904d02b3'
+    'test "$ptree" = "$expectedptree1"'
 
 test_expect_success \
     'writing partial tree out with git write-tree --prefix.' \
     'ptree=$(git write-tree --prefix=path3/subp3)'
 test_expect_success \
     'validate object ID for a known tree.' \
-    'test "$ptree" = 3c5e5399f3a333eddecce7a9b9465b63f65f51e2'
+    'test "$ptree" = "$expectedptree2"'
 
 cat >badobjects <<EOF
 100644 blob 1000000000000000000000000000000000000000	dir/file1
@@ -249,7 +268,7 @@ test_expect_success \
      newtree=$(git write-tree) &&
      test "$newtree" = "$tree"'
 
-cat >expected <<\EOF
+$expectfilter >expected <<\EOF
 :100644 100644 f87290f8eb2cbbea7857214459a0739927eab154 0000000000000000000000000000000000000000 M	path0
 :120000 120000 15a98433ae33114b085f3eb3bb03b832b3180a01 0000000000000000000000000000000000000000 M	path0sym
 :100644 100644 3feff949ed00a62d9f7af97c15cd8a30595e7ac7 0000000000000000000000000000000000000000 M	path2/file2
@@ -272,7 +291,7 @@ test_expect_success \
     'git diff-files >current && cmp -s current /dev/null'
 
 ################################################################
-P=087704a96baf1c2d1c869a8b084481e121c88b5b
+P=$expectedtree
 test_expect_success \
     'git commit-tree records the correct tree in a commit.' \
     'commit0=$(echo NO | git commit-tree $P) &&
@@ -308,7 +327,7 @@ test_expect_success 'update-index D/F conflict' '
 	test $numpath0 = 1
 '
 
-test_expect_success 'absolute path works as expected' '
+test_expect_success SYMLINKS 'absolute path works as expected' '
 	mkdir first &&
 	ln -s ../.git first/.git &&
 	mkdir second &&

t/t0055-beyond-symlinks.sh

@@ -4,20 +4,20 @@ test_description='update-index and add refuse to add beyond symlinks'
 
 . ./test-lib.sh
 
-test_expect_success setup '
+test_expect_success SYMLINKS setup '
 	>a &&
 	mkdir b &&
 	ln -s b c &&
 	>c/d &&
 	git update-index --add a b/d
 '
 
-test_expect_success 'update-index --add beyond symlinks' '
+test_expect_success SYMLINKS 'update-index --add beyond symlinks' '
 	test_must_fail git update-index --add c/d &&
 	! ( git ls-files | grep c/d )
 '
 
-test_expect_success 'add beyond symlinks' '
+test_expect_success SYMLINKS 'add beyond symlinks' '
 	test_must_fail git add c/d &&
 	! ( git ls-files | grep c/d )
 '

t/t1004-read-tree-m-u-wf.sh

@@ -157,7 +157,7 @@ test_expect_success '3-way not overwriting local changes (their side)' '
 
 '
 
-test_expect_success 'funny symlink in work tree' '
+test_expect_success SYMLINKS 'funny symlink in work tree' '
 
 	git reset --hard &&
 	git checkout -b sym-b side-b &&
@@ -177,7 +177,7 @@ test_expect_success 'funny symlink in work tree' '
 
 '
 
-test_expect_success 'funny symlink in work tree, un-unlink-able' '
+test_expect_success SYMLINKS 'funny symlink in work tree, un-unlink-able' '
 
 	rm -fr a b &&
 	git reset --hard &&
@@ -189,7 +189,7 @@ test_expect_success 'funny symlink in work tree, un-unlink-able' '
 '
 
 # clean-up from the above test
-chmod a+w a
+chmod a+w a 2>/dev/null
 rm -fr a b
 
 test_expect_success 'D/F setup' '

t/t1020-subdirectory.sh

@@ -126,7 +126,7 @@ test_expect_success 'no file/rev ambiguity check inside a bare repo' '
 	cd foo.git && git show -s HEAD
 '
 
-test_expect_success 'detection should not be fooled by a symlink' '
+test_expect_success SYMLINKS 'detection should not be fooled by a symlink' '
 	cd "$HERE" &&
 	rm -fr foo.git &&
 	git clone -s .git another &&

t/t1300-repo-config.sh

@@ -726,7 +726,7 @@ echo >>result
 
 test_expect_success '--null --get-regexp' 'cmp result expect'
 
-test_expect_success 'symlinked configuration' '
+test_expect_success SYMLINKS 'symlinked configuration' '
 
 	ln -s notyet myconfig &&
 	GIT_CONFIG=myconfig git config test.frotz nitfol &&

t/t2001-checkout-cache-clash.sh

@@ -59,10 +59,10 @@ test_expect_success \
     'git read-tree -m $tree1 && git checkout-index -f -a'
 test_debug 'show_files $tree1'
 
-ln -s path0 path1
-test_expect_success \
+test_expect_success SYMLINKS \
     'git update-index --add a symlink.' \
-    'git update-index --add path1'
+    'ln -s path0 path1 &&
+     git update-index --add path1'
 test_expect_success \
     'writing tree out with git write-tree' \
     'tree3=$(git write-tree)'

t/t2003-checkout-cache-mkdir.sh

@@ -19,7 +19,7 @@ test_expect_success \
     echo rezrov >path1/file1 &&
     git update-index --add path0 path1/file1'
 
-test_expect_success \
+test_expect_success SYMLINKS \
     'have symlink in place where dir is expected.' \
     'rm -fr path0 path1 &&
      mkdir path2 &&
@@ -59,7 +59,7 @@ test_expect_success \
      test ! -f path1/file1'
 
 # Linus fix #1
-test_expect_success \
+test_expect_success SYMLINKS \
     'use --prefix=tmp/orary/ where tmp is a symlink' \
     'rm -fr path0 path1 path2 tmp* &&
      mkdir tmp1 tmp1/orary &&
@@ -71,7 +71,7 @@ test_expect_success \
      test -h tmp'
 
 # Linus fix #2
-test_expect_success \
+test_expect_success SYMLINKS \
     'use --prefix=tmp/orary- where tmp is a symlink' \
     'rm -fr path0 path1 path2 tmp* &&
      mkdir tmp1 &&
@@ -82,7 +82,7 @@ test_expect_success \
      test -h tmp'
 
 # Linus fix #3
-test_expect_success \
+test_expect_success SYMLINKS \
     'use --prefix=tmp- where tmp-path1 is a symlink' \
     'rm -fr path0 path1 path2 tmp* &&
      mkdir tmp1 &&

t/t2004-checkout-cache-temp.sh

@@ -194,7 +194,7 @@ test_expect_success \
  test $(cat ../$s1) = tree1asubdir/path5)
 )'
 
-test_expect_success \
+test_expect_success SYMLINKS \
 'checkout --temp symlink' '
 rm -f path* .merge_* out .git/index &&
 ln -s b a &&

t/t2007-checkout-symlink.sh

@@ -6,6 +6,12 @@ test_description='git checkout to switch between branches with symlink<->dir'
 
 . ./test-lib.sh
 
+if ! test_have_prereq SYMLINKS
+then
+	say "symbolic links not supported - skipping tests"
+	test_done
+fi
+
 test_expect_success setup '
 
 	mkdir frotz &&

t/t2100-update-cache-badpath.sh

@@ -26,7 +26,12 @@ All of the attempts should fail.
 
 mkdir path2 path3
 date >path0
-ln -s xyzzy path1
+if test_have_prereq SYMLINKS
+then
+	ln -s xyzzy path1
+else
+	date > path1
+fi
 date >path2/file2
 date >path3/file3
 
@@ -38,7 +43,12 @@ rm -fr path?
 
 mkdir path0 path1
 date >path2
-ln -s frotz path3
+if test_have_prereq SYMLINKS
+then
+	ln -s frotz path3
+else
+	date > path3
+fi
 date >path0/file0
 date >path1/file1
 

t/t2200-add-update.sh

@@ -80,7 +80,7 @@ test_expect_success 'change gets noticed' '
 
 '
 
-test_expect_success 'replace a file with a symlink' '
+test_expect_success SYMLINKS 'replace a file with a symlink' '
 
 	rm foo &&
 	ln -s top foo &&

t/t2201-add-update-typechange.sh

@@ -11,7 +11,13 @@ test_expect_success setup '
 	_empty=$(git hash-object --stdin <xyzzy) &&
 	>yomin &&
 	>caskly &&
-	ln -s frotz nitfol &&
+	if test_have_prereq SYMLINKS; then
+		ln -s frotz nitfol &&
+		T_letter=T
+	else
+		printf %s frotz > nitfol &&
+		T_letter=M
+	fi &&
 	mkdir rezrov &&
 	>rezrov/bozbar &&
 	git add caskly xyzzy yomin nitfol rezrov/bozbar &&
@@ -29,7 +35,11 @@ test_expect_success modify '
 	>nitfol &&
 	# rezrov/bozbar disappears
 	rm -fr rezrov &&
-	ln -s xyzzy rezrov &&
+	if test_have_prereq SYMLINKS; then
+		ln -s xyzzy rezrov
+	else
+		printf %s xyzzy > rezrov
+	fi &&
 	# xyzzy disappears (not a submodule)
 	mkdir xyzzy &&
 	echo gnusto >xyzzy/bozbar &&
@@ -71,7 +81,7 @@ test_expect_success modify '
 				s/blob/000000/
 			}
 			/	nitfol/{
-				s/	nitfol/ $_z40 T&/
+				s/	nitfol/ $_z40 $T_letter&/
 				s/blob/100644/
 			}
 			/	rezrov.bozbar/{

t/t2300-cd-to-toplevel.sh

@@ -5,7 +5,7 @@ test_description='cd_to_toplevel'
 . ./test-lib.sh
 
 test_cd_to_toplevel () {
-	test_expect_success "$2" '
+	test_expect_success $3 "$2" '
 		(
 			cd '"'$1'"' &&
 			. git-sh-setup &&
@@ -24,14 +24,14 @@ test_cd_to_toplevel repo 'at physical root'
 
 test_cd_to_toplevel repo/sub/dir 'at physical subdir'
 
-ln -s repo symrepo
-test_cd_to_toplevel symrepo 'at symbolic root'
+ln -s repo symrepo 2>/dev/null
+test_cd_to_toplevel symrepo 'at symbolic root' SYMLINKS
 
-ln -s repo/sub/dir subdir-link
-test_cd_to_toplevel subdir-link 'at symbolic subdir'
+ln -s repo/sub/dir subdir-link 2>/dev/null
+test_cd_to_toplevel subdir-link 'at symbolic subdir' SYMLINKS
 
 cd repo
-ln -s sub/dir internal-link
-test_cd_to_toplevel internal-link 'at internal symbolic subdir'
+ln -s sub/dir internal-link 2>/dev/null
+test_cd_to_toplevel internal-link 'at internal symbolic subdir' SYMLINKS
 
 test_done

t/t3000-ls-files-others.sh

@@ -17,7 +17,12 @@ filesystem.
 . ./test-lib.sh
 
 date >path0
-ln -s xyzzy path1
+if test_have_prereq SYMLINKS
+then
+	ln -s xyzzy path1
+else
+	date > path1
+fi
 mkdir path2 path3
 date >path2/file2
 date >path2-junk