apply: notice creation/removal patches produced by GNU diff

Unified context patch generated by GNU diff has UNIX epoch timestamp
on the side that does not exist when the patch is about a creation or
a deletion event.  Notice this convention when reading a non-git diff.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-apply.c b/builtin-apply.c
index dc0ff5e08ae73f2832fd4451cce2e849c88be5a8..39dc96ae0237235eb429b504ec28c9d66c32f4e1 100644 (file)
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -457,6 +457,76 @@ static int guess_p_value(const char *nameline)
        return val;
 }
 
+/*
+ * Does the ---/+++ line has the POSIX timestamp after the last HT?
+ * GNU diff puts epoch there to signal a creation/deletion event.  Is
+ * this such a timestamp?
+ */
+static int has_epoch_timestamp(const char *nameline)
+{
+       /*
+        * We are only interested in epoch timestamp; any non-zero
+        * fraction cannot be one, hence "(\.0+)?" in the regexp below.
+        * For the same reason, the date must be either 1969-12-31 or
+        * 1970-01-01, and the seconds part must be "00".
+        */
+       const char stamp_regexp[] =
+               "^(1969-12-31|1970-01-01)"
+               " "
+               "[0-2][0-9]:[0-5][0-9]:00(\\.0+)?"
+               " "
+               "([-+][0-2][0-9][0-5][0-9])\n";
+       const char *timestamp = NULL, *cp;
+       static regex_t *stamp;
+       regmatch_t m[10];
+       int zoneoffset;
+       int hourminute;
+       int status;
+
+       for (cp = nameline; *cp != '\n'; cp++) {
+               if (*cp == '\t')
+                       timestamp = cp + 1;
+       }
+       if (!timestamp)
+               return 0;
+       if (!stamp) {
+               stamp = xmalloc(sizeof(*stamp));
+               if (regcomp(stamp, stamp_regexp, REG_EXTENDED)) {
+                       warning("Cannot prepare timestamp regexp %s",
+                               stamp_regexp);
+                       return 0;
+               }
+       }
+
+       status = regexec(stamp, timestamp, ARRAY_SIZE(m), m, 0);
+       if (status) {
+               if (status != REG_NOMATCH)
+                       warning("regexec returned %d for input: %s",
+                               status, timestamp);
+               return 0;
+       }
+
+       zoneoffset = strtol(timestamp + m[3].rm_so + 1, NULL, 10);
+       zoneoffset = (zoneoffset / 100) * 60 + (zoneoffset % 100);
+       if (timestamp[m[3].rm_so] == '-')
+               zoneoffset = -zoneoffset;
+
+       /*
+        * YYYY-MM-DD hh:mm:ss must be from either 1969-12-31
+        * (west of GMT) or 1970-01-01 (east of GMT)
+        */
+       if ((zoneoffset < 0 && memcmp(timestamp, "1969-12-31", 10)) ||
+           (0 <= zoneoffset && memcmp(timestamp, "1970-01-01", 10)))
+               return 0;
+
+       hourminute = (strtol(timestamp + 11, NULL, 10) * 60 +
+                     strtol(timestamp + 14, NULL, 10) -
+                     zoneoffset);
+
+       return ((zoneoffset < 0 && hourminute == 1440) ||
+               (0 <= zoneoffset && !hourminute));
+}
+
 /*
  * Get the name etc info from the ---/+++ lines of a traditional patch header
  *
@@ -493,7 +563,17 @@ static void parse_traditional_patch(const char *first, const char *second, struc
        } else {
                name = find_name(first, NULL, p_value, TERM_SPACE | TERM_TAB);
                name = find_name(second, name, p_value, TERM_SPACE | TERM_TAB);
-               patch->old_name = patch->new_name = name;
+               if (has_epoch_timestamp(first)) {
+                       patch->is_new = 1;
+                       patch->is_delete = 0;
+                       patch->new_name = name;
+               } else if (has_epoch_timestamp(second)) {
+                       patch->is_new = 0;
+                       patch->is_delete = 1;
+                       patch->old_name = name;
+               } else {
+                       patch->old_name = patch->new_name = name;
+               }
        }
        if (!name)
                die("unable to find filename in patch at line %d", linenr);

diff --git a/t/t4132-apply-removal.sh b/t/t4132-apply-removal.sh
new file mode 100755 (executable)
index 0000000..bb1ffe3
--- /dev/null
+++ b/t/t4132-apply-removal.sh
@@ -0,0 +1,95 @@
+#!/bin/sh
+#
+# Copyright (c) 2009 Junio C Hamano
+
+test_description='git-apply notices removal patches generated by GNU diff'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+       cat <<-EOF >c &&
+       diff -ruN a/file b/file
+       --- a/file      TS0
+       +++ b/file      TS1
+       @@ -0,0 +1 @@
+       +something
+       EOF
+
+       cat <<-EOF >d &&
+       diff -ruN a/file b/file
+       --- a/file      TS0
+       +++ b/file      TS1
+       @@ -1 +0,0 @@
+       -something
+       EOF
+
+       timeWest="1982-09-16 07:00:00.000000000 -0800" &&
+        timeGMT="1982-09-16 15:00:00.000000000 +0000" &&
+       timeEast="1982-09-17 00:00:00.000000000 +0900" &&
+
+       epocWest="1969-12-31 16:00:00.000000000 -0800" &&
+        epocGMT="1970-01-01 00:00:00.000000000 +0000" &&
+       epocEast="1970-01-01 09:00:00.000000000 +0900" &&
+
+       sed -e "s/TS0/$epocWest/" -e "s/TS1/$timeWest/" <c >createWest.patch &&
+       sed -e "s/TS0/$epocEast/" -e "s/TS1/$timeEast/" <c >createEast.patch &&
+       sed -e "s/TS0/$epocGMT/" -e "s/TS1/$timeGMT/" <c >createGMT.patch &&
+
+       sed -e "s/TS0/$timeWest/" -e "s/TS1/$timeWest/" <c >addWest.patch &&
+       sed -e "s/TS0/$timeEast/" -e "s/TS1/$timeEast/" <c >addEast.patch &&
+       sed -e "s/TS0/$timeGMT/" -e "s/TS1/$timeGMT/" <c >addGMT.patch &&
+
+       sed -e "s/TS0/$timeWest/" -e "s/TS1/$timeWest/" <d >emptyWest.patch &&
+       sed -e "s/TS0/$timeEast/" -e "s/TS1/$timeEast/" <d >emptyEast.patch &&
+       sed -e "s/TS0/$timeGMT/" -e "s/TS1/$timeGMT/" <d >emptyGMT.patch &&
+
+       sed -e "s/TS0/$timeWest/" -e "s/TS1/$epocWest/" <d >removeWest.patch &&
+       sed -e "s/TS0/$timeEast/" -e "s/TS1/$epocEast/" <d >removeEast.patch &&
+       sed -e "s/TS0/$timeGMT/" -e "s/TS1/$epocGMT/" <d >removeGMT.patch &&
+
+       echo something >something &&
+       >empty
+'
+
+for patch in *.patch
+do
+       test_expect_success "test $patch" '
+               rm -f file .git/index &&
+               case "$patch" in
+               create*)
+                       # must be able to create
+                       git apply --index $patch &&
+                       test_cmp file something &&
+                       # must notice the file is already there
+                       >file &&
+                       git add file &&
+                       test_must_fail git apply $patch
+                       ;;
+               add*)
+                       # must be able to create or patch
+                       git apply $patch &&
+                       test_cmp file something &&
+                       >file &&
+                       git apply $patch &&
+                       test_cmp file something
+                       ;;
+               empty*)
+                       # must leave an empty file
+                       cat something >file &&
+                       git add file &&
+                       git apply --index $patch &&
+                       test -f file &&
+                       test_cmp empty file
+                       ;;
+               remove*)
+                       # must remove the file
+                       cat something >file &&
+                       git add file &&
+                       git apply --index $patch &&
+                       ! test -f file
+                       ;;
+               esac
+       '
+done
+
+test_done