git-p4: fix Git LFS pointer parsing

Git LFS 1.2.0 removed a preamble from the output of the 'git lfs pointer'
command [1] which broke the parsing of this output. Adjust the parser
to support the old and the new format.

Please note that this patch slightly changes the second return parameter
from a list of LF terminated strings to a single string that contains
a number of LF characters.

[1] git-lfs/git-lfs@da2935d

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Helped-by: Sebastian Schuberth <sschuberth@gmail.com>
Helped-by: Ben Woosley <ben.woosley@gmail.com>
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: larsxschneider

git-p4.py

@@ -1064,16 +1064,23 @@ def generatePointer(self, contentFile):
         if pointerProcess.wait():
             os.remove(contentFile)
             die('git-lfs pointer command failed. Did you install the extension?')
-        pointerContents = [i+'\n' for i in pointerFile.split('\n')[2:][:-1]]
-        oid = pointerContents[1].split(' ')[1].split(':')[1][:-1]
+
+        # Git LFS removed the preamble in the output of the 'pointer' command
+        # starting from version 1.2.0. Check for the preamble here to support
+        # earlier versions.
+        # c.f. https://github.com/github/git-lfs/commit/da2935d9a739592bc775c98d8ef4df9c72ea3b43
+        if pointerFile.startswith('Git LFS pointer for'):
+            pointerFile = re.sub(r'Git LFS pointer for.*\n\n', '', pointerFile)
+
+        oid = re.search(r'^oid \w+:(\w+)', pointerFile, re.MULTILINE).group(1)
         localLargeFile = os.path.join(
             os.getcwd(),
             '.git', 'lfs', 'objects', oid[:2], oid[2:4],
             oid,
         )
         # LFS Spec states that pointer files should not have the executable bit set.
         gitMode = '100644'
-        return (gitMode, pointerContents, localLargeFile)
+        return (gitMode, pointerFile, localLargeFile)
 
     def pushFile(self, localLargeFile):
         uploadProcess = subprocess.Popen(

t/t9824-git-p4-git-lfs.sh

@@ -13,6 +13,10 @@ test_file_in_lfs () {
 	FILE="$1" &&
 	SIZE="$2" &&
 	EXPECTED_CONTENT="$3" &&
+	sed -n '1,1 p' "$FILE" | grep "^version " &&
+	sed -n '2,2 p' "$FILE" | grep "^oid " &&
+	sed -n '3,3 p' "$FILE" | grep "^size " &&
+	test_line_count = 3 "$FILE" &&
 	cat "$FILE" | grep "size $SIZE" &&
 	HASH=$(cat "$FILE" | grep "oid sha256:" | sed -e "s/oid sha256://g") &&
 	LFS_FILE=".git/lfs/objects/$(echo "$HASH" | cut -c1-2)/$(echo "$HASH" | cut -c3-4)/$HASH" &&