git/t/t4011-diff-symlink.sh
Junio C Hamano b3f01ff29f diff -p: squelch "diff --git" header for stat-dirty paths
The plumbing "diff" commands look at the working tree files without
refreshing the index themselves for performance reasons (the calling
script is expected to do that upfront just once, before calling one or
more of them).  In the early days of git, they showed the "diff --git"
header before they actually ask the xdiff machinery to produce patches,
and ended up showing only these headers if the real contents are the same
and the difference they noticed was only because the stat info cached in
the index did not match that of the working tree. It was too late for the
implementation to take the header that it already emitted back.

But 3e97c7c (No diff -b/-w output for all-whitespace changes, 2009-11-19)
introduced necessary logic to keep the meta-information headers in a
strbuf and delay their output until the xdiff machinery noticed actual
changes. This was primarily in order to generate patches that ignore
whitespaces. When operating under "-w" mode, we wouldn't know if the
header is needed until we actually look at the resulting patch, so it was
a sensible thing to do, but we did not realize that the same reasoning
applies to stat-dirty paths.

Later, 296c6bb (diff: fix "git show -C -C" output when renaming a binary
file, 2010-05-26) generalized this machinery and added must_show_header
toggle.  This is turned on when the header must be shown even when there
is no patch to be produced, e.g. only the mode was changed, or the path
was renamed, without changing the contents.  However, when it did so, it
still kept the special case for the "-w" mode, which meant that the
plumbing would keep showing these phantom changes.

This corrects this historical inconsistency by allowing the plumbing to
omit paths that are only stat-dirty from its output in the same way as it
handles whitespace only changes under "-w" option.

The change in the behaviour can be seen in the updated test.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-03-01 12:00:01 -08:00

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#!/bin/sh
#
# Copyright (c) 2005 Johannes Schindelin
#
test_description='Test diff of symlinks.
'
. ./test-lib.sh
. "$TEST_DIRECTORY"/diff-lib.sh
test_expect_success SYMLINKS 'diff new symlink and file' '
cat >expected <<-\EOF &&
diff --git a/frotz b/frotz
new file mode 120000
index 0000000..7c465af
--- /dev/null
+++ b/frotz
@@ -0,0 +1 @@
+xyzzy
\ No newline at end of file
diff --git a/nitfol b/nitfol
new file mode 100644
index 0000000..7c465af
--- /dev/null
+++ b/nitfol
@@ -0,0 +1 @@
+xyzzy
EOF
ln -s xyzzy frotz &&
echo xyzzy >nitfol &&
git update-index &&
tree=$(git write-tree) &&
git update-index --add frotz nitfol &&
GIT_DIFF_OPTS=--unified=0 git diff-index -M -p $tree >current &&
compare_diff_patch expected current
'
test_expect_success SYMLINKS 'diff unchanged symlink and file' '
tree=$(git write-tree) &&
git update-index frotz nitfol &&
test -z "$(git diff-index --name-only $tree)"
'
test_expect_success SYMLINKS 'diff removed symlink and file' '
cat >expected <<-\EOF &&
diff --git a/frotz b/frotz
deleted file mode 120000
index 7c465af..0000000
--- a/frotz
+++ /dev/null
@@ -1 +0,0 @@
-xyzzy
\ No newline at end of file
diff --git a/nitfol b/nitfol
deleted file mode 100644
index 7c465af..0000000
--- a/nitfol
+++ /dev/null
@@ -1 +0,0 @@
-xyzzy
EOF
mv frotz frotz2 &&
mv nitfol nitfol2 &&
git diff-index -M -p $tree >current &&
compare_diff_patch expected current
'
test_expect_success SYMLINKS 'diff identical, but newly created symlink and file' '
>expected &&
rm -f frotz nitfol &&
echo xyzzy >nitfol &&
test-chmtime +10 nitfol &&
ln -s xyzzy frotz &&
git diff-index -M -p $tree >current &&
compare_diff_patch expected current &&
>expected &&
git diff-index -M -p -w $tree >current &&
compare_diff_patch expected current
'
test_expect_success SYMLINKS 'diff different symlink and file' '
cat >expected <<-\EOF &&
diff --git a/frotz b/frotz
index 7c465af..df1db54 120000
--- a/frotz
+++ b/frotz
@@ -1 +1 @@
-xyzzy
\ No newline at end of file
+yxyyz
\ No newline at end of file
diff --git a/nitfol b/nitfol
index 7c465af..df1db54 100644
--- a/nitfol
+++ b/nitfol
@@ -1 +1 @@
-xyzzy
+yxyyz
EOF
rm -f frotz &&
ln -s yxyyz frotz &&
echo yxyyz >nitfol &&
git diff-index -M -p $tree >current &&
compare_diff_patch expected current
'
test_expect_success SYMLINKS 'diff symlinks with non-existing targets' '
ln -s narf pinky &&
ln -s take\ over brain &&
test_must_fail git diff --no-index pinky brain >output 2>output.err &&
grep narf output &&
! test -s output.err
'
test_expect_success SYMLINKS 'setup symlinks with attributes' '
echo "*.bin diff=bin" >>.gitattributes &&
echo content >file.bin &&
ln -s file.bin link.bin &&
git add -N file.bin link.bin
'
test_expect_success SYMLINKS 'symlinks do not respect userdiff config by path' '
cat >expect <<-\EOF &&
diff --git a/file.bin b/file.bin
index e69de29..d95f3ad 100644
Binary files a/file.bin and b/file.bin differ
diff --git a/link.bin b/link.bin
index e69de29..dce41ec 120000
--- a/link.bin
+++ b/link.bin
@@ -0,0 +1 @@
+file.bin
\ No newline at end of file
EOF
git config diff.bin.binary true &&
git diff file.bin link.bin >actual &&
test_cmp expect actual
'
test_done