pull: fast-forward working tree if head is updated
Since b10ac50 (Fix pulling into the same branch., 2005-08-25), git-pull, upon detecting that git-fetch updated the current head, will fast-forward the working tree to the updated head commit. Re-implement this behavior. Signed-off-by: Paul Tan <pyokagan@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Paul Tan committed
Jun 18, 2015 at 18:54 UTC
fe911b8ca0b466697b38880512ea2b28f2699dbd
1 file changed
+30
builtin/pull.c
+30
@@ -412,6 +412,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
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{
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const char *repo, **refspecs;
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struct sha1_array merge_heads = SHA1_ARRAY_INIT;
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+ unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
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if (!getenv("_GIT_USE_BUILTIN_PULL")) {
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const char *path = mkpath("%s/git-pull", git_exec_path());
@@ -435,12 +436,41 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
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if (file_exists(git_path("MERGE_HEAD")))
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die_conclude_merge();
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+ if (get_sha1("HEAD", orig_head))
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+ hashclr(orig_head);
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+
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if (run_fetch(repo, refspecs))
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return 1;
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if (opt_dry_run)
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return 0;
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+ if (get_sha1("HEAD", curr_head))
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+ hashclr(curr_head);
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+
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+ if (!is_null_sha1(orig_head) && !is_null_sha1(curr_head) &&
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+ hashcmp(orig_head, curr_head)) {
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+ /*
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+ * The fetch involved updating the current branch.
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+ *
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+ * The working tree and the index file are still based on
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+ * orig_head commit, but we are merging into curr_head.
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+ * Update the working tree to match curr_head.
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+ */
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+
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+ warning(_("fetch updated the current branch head.\n"
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+ "fast-forwarding your working tree from\n"
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+ "commit %s."), sha1_to_hex(orig_head));
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+
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+ if (checkout_fast_forward(orig_head, curr_head, 0))
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+ die(_("Cannot fast-forward your working tree.\n"
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+ "After making sure that you saved anything precious from\n"
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+ "$ git diff %s\n"
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+ "output, run\n"
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+ "$ git reset --hard\n"
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+ "to recover."), sha1_to_hex(orig_head));
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+ }
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+
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get_merge_heads(&merge_heads);
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if (!merge_heads.nr)