do not overwrite untracked during merge from unborn branch
In case HEAD does not point to a valid commit yet, merge is implemented as a hard reset. This will cause untracked files to be overwritten. Instead, assume the empty tree for HEAD and do a regular merge. An untracked file will cause the merge to abort and do nothing. If no conflicting files are present, the merge will have the same effect as a hard reset. Signed-off-by: Clemens Buchacher <drizzd@aon.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Clemens Buchacher committed
Nov 14, 2010 at 23:07 UTC
172b6428d06ff4eb0812f087a497d50b6c878fe1
2 files changed
+35
-1
builtin/merge.c
+19
-1
@@ -231,6 +231,24 @@ static void save_state(void)
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die("not a valid object: %s", buffer.buf);
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}
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+static void read_empty(unsigned const char *sha1, int verbose)
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+{
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+ int i = 0;
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+ const char *args[7];
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+
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+ args[i++] = "read-tree";
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+ if (verbose)
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+ args[i++] = "-v";
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+ args[i++] = "-m";
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+ args[i++] = "-u";
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+ args[i++] = EMPTY_TREE_SHA1_HEX;
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+ args[i++] = sha1_to_hex(sha1);
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+ args[i] = NULL;
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+
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+ if (run_command_v_opt(args, RUN_GIT_CMD))
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+ die("read-tree failed");
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+}
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+
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static void reset_hard(unsigned const char *sha1, int verbose)
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{
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int i = 0;
@@ -979,7 +997,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
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die("%s - not something we can merge", argv[0]);
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update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
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DIE_ON_ERR);
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- reset_hard(remote_head->sha1, 0);
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+ read_empty(remote_head->sha1, 0);
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return 0;
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} else {
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struct strbuf merge_names = STRBUF_INIT;
t/t7607-merge-overwrite.sh
+16
@@ -84,4 +84,20 @@ test_expect_success 'will not overwrite removed file with staged changes' '
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test_cmp important c1.c
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'
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+cat >expect <<\EOF
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+error: Untracked working tree file 'c0.c' would be overwritten by merge.
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+fatal: read-tree failed
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+EOF
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+
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+test_expect_success 'will not overwrite untracked file on unborn branch' '
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+ git reset --hard c0 &&
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+ git rm -fr . &&
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+ git checkout --orphan new &&
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+ cp important c0.c &&
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+ test_must_fail git merge c0 2>out &&
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+ test_cmp out expect &&
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+ test_path_is_missing .git/MERGE_HEAD &&
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+ test_cmp important c0.c
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+'
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+
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test_done