tests: add a test to demonstrate a bug in `hg diff --git` (issue6486)

Issue url: https://bz.mercurial-scm.org/show_bug.cgi?id=6486
This will be fixed in next patch.

Differential Revision: https://phab.mercurial-scm.org/D10000

tests/test-diff-unified.t

@@ -1,458 +1,481 b''
   $ hg init repo
   $ cd repo
   $ cat > a <<EOF
   > c
   > c
   > a
   > a
   > b
   > a
   > a
   > c
   > c
   > EOF
   $ hg ci -Am adda
   adding a
 
   $ cat > a <<EOF
   > c
   > c
   > a
   > a
   > dd
   > a
   > a
   > c
   > c
   > EOF
 
 default context
 
   $ hg diff --nodates
   diff -r cf9f4ba66af2 a
   --- a/a
   +++ b/a
   @@ -2,7 +2,7 @@
    c
    a
    a
   -b
   +dd
    a
    a
    c
 
 invalid --unified
 
   $ hg diff --nodates -U foo
   abort: diff context lines count must be an integer, not 'foo'
   [255]
 
 
   $ hg diff --nodates -U 2
   diff -r cf9f4ba66af2 a
   --- a/a
   +++ b/a
   @@ -3,5 +3,5 @@
    a
    a
   -b
   +dd
    a
    a
 
   $ hg --config diff.unified=2 diff --nodates
   diff -r cf9f4ba66af2 a
   --- a/a
   +++ b/a
   @@ -3,5 +3,5 @@
    a
    a
   -b
   +dd
    a
    a
 
   $ hg diff --nodates -U 1
   diff -r cf9f4ba66af2 a
   --- a/a
   +++ b/a
   @@ -4,3 +4,3 @@
    a
   -b
   +dd
    a
 
 invalid diff.unified
 
   $ hg --config diff.unified=foo diff --nodates
   abort: diff context lines count must be an integer, not 'foo'
   [255]
 
 noprefix config and option
 
   $ hg --config diff.noprefix=True diff --nodates
   diff -r cf9f4ba66af2 a
   --- a
   +++ a
   @@ -2,7 +2,7 @@
    c
    a
    a
   -b
   +dd
    a
    a
    c
   $ hg diff --noprefix --nodates
   diff -r cf9f4ba66af2 a
   --- a
   +++ a
   @@ -2,7 +2,7 @@
    c
    a
    a
   -b
   +dd
    a
    a
    c
 
 noprefix config disabled in plain mode, but option still enabled
 
   $ HGPLAIN=1 hg --config diff.noprefix=True diff --nodates
   diff -r cf9f4ba66af2 a
   --- a/a
   +++ b/a
   @@ -2,7 +2,7 @@
    c
    a
    a
   -b
   +dd
    a
    a
    c
   $ HGPLAIN=1 hg diff --noprefix --nodates
   diff -r cf9f4ba66af2 a
   --- a
   +++ a
   @@ -2,7 +2,7 @@
    c
    a
    a
   -b
   +dd
    a
    a
    c
 
   $ cd ..
 
 
 0 lines of context hunk header matches gnu diff hunk header
 
   $ hg init diffzero
   $ cd diffzero
   $ cat > f1 << EOF
   > c2
   > c4
   > c5
   > EOF
   $ hg commit -Am0
   adding f1
 
   $ cat > f2 << EOF
   > c1
   > c2
   > c3
   > c4
   > EOF
   $ mv f2 f1
   $ hg diff -U0 --nodates
   diff -r 55d8ff78db23 f1
   --- a/f1
   +++ b/f1
   @@ -0,0 +1,1 @@
   +c1
   @@ -1,0 +3,1 @@
   +c3
   @@ -3,1 +4,0 @@
   -c5
 
   $ hg diff -U0 --nodates --git
   diff --git a/f1 b/f1
   --- a/f1
   +++ b/f1
   @@ -0,0 +1,1 @@
   +c1
   @@ -1,0 +3,1 @@
   +c3
   @@ -3,1 +4,0 @@
   -c5
 
   $ hg diff -U0 --nodates -p
   diff -r 55d8ff78db23 f1
   --- a/f1
   +++ b/f1
   @@ -0,0 +1,1 @@
   +c1
   @@ -1,0 +3,1 @@ c2
   +c3
   @@ -3,1 +4,0 @@ c4
   -c5
 
   $ echo a > f1
   $ hg ci -m movef2
 
 Test diff headers terminating with TAB when necessary (issue3357)
 Regular diff --nodates, file creation
 
   $ hg mv f1 'f 1'
   $ echo b > 'f 1'
   $ hg diff --nodates 'f 1'
   diff -r 7574207d0d15 f 1
   --- /dev/null
   +++ b/f 1	
   @@ -0,0 +1,1 @@
   +b
 
 Git diff, adding space
 
   $ hg diff --git
   diff --git a/f1 b/f 1
   rename from f1
   rename to f 1
   --- a/f1
   +++ b/f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
 Git diff, adding extended headers
 
   $ hg diff --git --config experimental.extendedheader.index=7 --config experimental.extendedheader.similarity=True
   diff --git a/f1 b/f 1
   similarity index 0%
   rename from f1
   rename to f 1
   index 7898192..6178079 100644
   --- a/f1
   +++ b/f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
   $ hg diff --git --config experimental.extendedheader.index=-1
   invalid length for extendedheader.index: '-1'
   diff --git a/f1 b/f 1
   rename from f1
   rename to f 1
   --- a/f1
   +++ b/f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
   $ hg diff --git --config experimental.extendedheader.index=whatever
   invalid value for extendedheader.index: 'whatever'
   diff --git a/f1 b/f 1
   rename from f1
   rename to f 1
   --- a/f1
   +++ b/f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
 Git diff with noprefix
 
   $ hg --config diff.noprefix=True diff --git --nodates
   diff --git f1 f 1
   rename from f1
   rename to f 1
   --- f1
   +++ f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
 noprefix config disabled in plain mode, but option still enabled
 
   $ HGPLAIN=1 hg --config diff.noprefix=True diff --git --nodates
   diff --git a/f1 b/f 1
   rename from f1
   rename to f 1
   --- a/f1
   +++ b/f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
   $ HGPLAIN=1 hg diff --git --noprefix --nodates
   diff --git f1 f 1
   rename from f1
   rename to f 1
   --- f1
   +++ f 1	
   @@ -1,1 +1,1 @@
   -a
   +b
 
 Regular diff --nodates, file deletion
 
   $ hg ci -m addspace
   $ hg mv 'f 1' f1
   $ echo a > f1
   $ hg diff --nodates 'f 1'
   diff -r ca50fe67c9c7 f 1
   --- a/f 1	
   +++ /dev/null
   @@ -1,1 +0,0 @@
   -b
 
 Git diff, removing space
 
   $ hg diff --git
   diff --git a/f 1 b/f1
   rename from f 1
   rename to f1
   --- a/f 1	
   +++ b/f1
   @@ -1,1 +1,1 @@
   -b
   +a
 
 showfunc diff
   $ cat > f1 << EOF
   > int main() {
   >     int a = 0;
   >     int b = 1;
   >     int c = 2;
   >     int d = 3;
   >     return a + b + c + d;
   > }
   > EOF
   $ hg commit -m addfunction
   $ cat > f1 << EOF
   > int main() {
   >     int a = 0;
   >     int b = 1;
   >     int c = 2;
   >     int e = 3;
   >     return a + b + c + e;
   > }
   > EOF
   $ hg diff --git
   diff --git a/f1 b/f1
   --- a/f1
   +++ b/f1
   @@ -2,6 +2,6 @@
        int a = 0;
        int b = 1;
        int c = 2;
   -    int d = 3;
   -    return a + b + c + d;
   +    int e = 3;
   +    return a + b + c + e;
    }
   $ hg diff --config diff.showfunc=True --git
   diff --git a/f1 b/f1
   --- a/f1
   +++ b/f1
   @@ -2,6 +2,6 @@ int main() {
        int a = 0;
        int b = 1;
        int c = 2;
   -    int d = 3;
   -    return a + b + c + d;
   +    int e = 3;
   +    return a + b + c + e;
    }
 
 If [diff] git is set to true, but the user says --no-git, we should
 *not* get git diffs
   $ hg diff --nodates --config diff.git=1 --no-git
   diff -r f2c7c817fa55 f1
   --- a/f1
   +++ b/f1
   @@ -2,6 +2,6 @@
        int a = 0;
        int b = 1;
        int c = 2;
   -    int d = 3;
   -    return a + b + c + d;
   +    int e = 3;
   +    return a + b + c + e;
    }
 
   $ cd ..
 
 Long function names should be abbreviated, but multi-byte character shouldn't
 be broken up
 
   $ hg init longfunc
   $ cd longfunc
 
   >>> with open('a', 'wb') as f:
   ...     f.write(b'a' * 39 + b'bb' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 0 b\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b'a' * 39 + b'\xc3\xa0' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 0 a with grave (single code point)\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b'a' * 39 + b'a\xcc\x80' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 0 a with grave (composition)\n') and None
   ...     f.write(b' .\n' * 3) and None
   $ hg ci -qAm0
 
   >>> with open('a', 'wb') as f:
   ...     f.write(b'a' * 39 + b'bb' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 1 b\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b'a' * 39 + b'\xc3\xa0' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 1 a with grave (single code point)\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b'a' * 39 + b'a\xcc\x80' + b'\n') and None
   ...     f.write(b' .\n' * 3) and None
   ...     f.write(b' 1 a with grave (composition)\n') and None
   ...     f.write(b' .\n' * 3) and None
   $ hg ci -m1
 
   $ hg diff -c1 --nodates --show-function
   diff -r 3e92dd6fa812 -r a256341606cb a
   --- a/a
   +++ b/a
   @@ -2,7 +2,7 @@ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab
     .
     .
     .
   - 0 b
   + 1 b
     .
     .
     .
   @@ -10,7 +10,7 @@ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\xc3\xa0 (esc)
     .
     .
     .
   - 0 a with grave (single code point)
   + 1 a with grave (single code point)
     .
     .
     .
   @@ -18,7 +18,7 @@ aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\xcc\x80 (esc)
     .
     .
     .
   - 0 a with grave (composition)
   + 1 a with grave (composition)
     .
     .
     .
 
   $ cd ..
+
+Make sure `hg diff --git` differentiate "file did not exists" and "file is empty"
+for git blob oids
+
+  $ hg init bloboids
+  $ cd bloboids
+
+  $ touch a
+  $ hg ci -Am "empty a"
+  adding a
+  $ hg diff -c 0 --git --config experimental.extendedheader.index=full | grep index
+  index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 100644
+
+Make sure `hg diff --git` differentiate "file was empty" and "file is removed"
+for git blob oids
+
+  $ rm a
+  $ hg ci -Am "removed a"
+  removing a
+  $ hg diff -c 1 --git --config experimental.extendedheader.index=full | grep index
+  index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 100644
+
+  $ cd ..