This rewrites `git merge-one-file' from shell to C. This port is not
completely straightforward: to save precious cycles by avoiding reading
and flushing the index repeatedly, write temporary files when an
operation can be performed in-memory, or allow other function to use the
rewrite without forking nor worrying about the index, the calls to
external processes are replaced by calls to functions in libgit.a:
- calls to `update-index --add --cacheinfo' are replaced by calls to
add_to_index_cacheinfo();
- calls to `update-index --remove' are replaced by calls to
remove_file_from_index();
- calls to `checkout-index -u -f' are replaced by calls to
checkout_entry();
- calls to `unpack-file' and `merge-files' are replaced by calls to
read_mmblob() and xdl_merge(), respectively, to merge files
in-memory;
- calls to `checkout-index -f --stage=2' are removed, as this is needed
to have the correct permission bits on the merged file from the
script, but not in the C version;
- calls to `update-index' are replaced by calls to add_file_to_index().
The bulk of the rewrite is done in a new file in libgit.a,
merge-strategies.c. This will enable the resolve and octopus strategies
to directly call it instead of forking.
This also fixes a bug present in the original script: instead of
checking if a _regular_ file exists when a file exists in the branch to
merge, but not in our branch, the rewritten version checks if a file of
any kind (ie. a directory, ...) exists. This fixes the tests t6035.14,
where the branch to merge had a new file, `a/b', but our branch had a
directory there; it should have failed because a directory exists, but
it did not because there was no regular file called `a/b'. This test is
now marked as successful.
Signed-off-by: Alban Gruin <alban.gruin@xxxxxxxxx>
---
Makefile | 3 +-
builtin.h | 1 +
builtin/merge-one-file.c | 94 +++++++++++++++++
git-merge-one-file.sh | 167 ------------------------------
git.c | 1 +
merge-strategies.c | 176 ++++++++++++++++++++++++++++++++
merge-strategies.h | 12 +++
t/t6415-merge-dir-to-symlink.sh | 2 +-
8 files changed, 287 insertions(+), 169 deletions(-)
create mode 100644 builtin/merge-one-file.c
delete mode 100755 git-merge-one-file.sh
create mode 100644 merge-strategies.c
create mode 100644 merge-strategies.h
diff --git a/Makefile b/Makefile
index de53954590..6dfdb33cb2 100644
--- a/Makefile
+++ b/Makefile
@@ -601,7 +601,6 @@ SCRIPT_SH += git-bisect.sh
SCRIPT_SH += git-difftool--helper.sh
SCRIPT_SH += git-filter-branch.sh
SCRIPT_SH += git-merge-octopus.sh
-SCRIPT_SH += git-merge-one-file.sh
SCRIPT_SH += git-merge-resolve.sh
SCRIPT_SH += git-mergetool.sh
SCRIPT_SH += git-quiltimport.sh
@@ -909,6 +908,7 @@ LIB_OBJS += match-trees.o
LIB_OBJS += mem-pool.o
LIB_OBJS += merge-blobs.o
LIB_OBJS += merge-recursive.o
+LIB_OBJS += merge-strategies.o
LIB_OBJS += merge.o
LIB_OBJS += mergesort.o
LIB_OBJS += midx.o
@@ -1094,6 +1094,7 @@ BUILTIN_OBJS += builtin/mailsplit.o
BUILTIN_OBJS += builtin/merge-base.o
BUILTIN_OBJS += builtin/merge-file.o
BUILTIN_OBJS += builtin/merge-index.o
+BUILTIN_OBJS += builtin/merge-one-file.o
BUILTIN_OBJS += builtin/merge-ours.o
BUILTIN_OBJS += builtin/merge-recursive.o
BUILTIN_OBJS += builtin/merge-tree.o
diff --git a/builtin.h b/builtin.h
index 53fb290963..4d2cd78856 100644
--- a/builtin.h
+++ b/builtin.h
@@ -178,6 +178,7 @@ int cmd_merge_base(int argc, const char **argv, const char *prefix);
int cmd_merge_index(int argc, const char **argv, const char *prefix);
int cmd_merge_ours(int argc, const char **argv, const char *prefix);
int cmd_merge_file(int argc, const char **argv, const char *prefix);
+int cmd_merge_one_file(int argc, const char **argv, const char *prefix);
int cmd_merge_recursive(int argc, const char **argv, const char *prefix);
int cmd_merge_tree(int argc, const char **argv, const char *prefix);
int cmd_mktag(int argc, const char **argv, const char *prefix);
diff --git a/builtin/merge-one-file.c b/builtin/merge-one-file.c
new file mode 100644
index 0000000000..9c21778e1d
--- /dev/null
+++ b/builtin/merge-one-file.c
@@ -0,0 +1,94 @@
+/*
+ * Builtin "git merge-one-file"
+ *
+ * Copyright (c) 2020 Alban Gruin
+ *
+ * Based on git-merge-one-file.sh, written by Linus Torvalds.
+ *
+ * This is the git per-file merge utility, called with
+ *
+ * argv[1] - original file object name (or empty)
+ * argv[2] - file in branch1 object name (or empty)
+ * argv[3] - file in branch2 object name (or empty)
+ * argv[4] - pathname in repository
+ * argv[5] - original file mode (or empty)
+ * argv[6] - file in branch1 mode (or empty)
+ * argv[7] - file in branch2 mode (or empty)
+ *
+ * Handle some trivial cases. The _really_ trivial cases have been
+ * handled already by git read-tree, but that one doesn't do any merges
+ * that might change the tree layout.
+ */
+
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
+#include "cache.h"
+#include "builtin.h"
+#include "lockfile.h"
+#include "merge-strategies.h"
+
+static const char builtin_merge_one_file_usage[] =
+ "git merge-one-file <orig blob> <our blob> <their blob> <path> "
+ "<orig mode> <our mode> <their mode>\n\n"
+ "Blob ids and modes should be empty for missing files.";
+
+static int read_mode(const char *name, const char *arg, unsigned int *mode)
+{
+ char *last;
+ int ret = 0;
+
+ *mode = strtol(arg, &last, 8);
+
+ if (*last)
+ ret = error(_("invalid '%s' mode: expected nothing, got '%c'"), name, *last);
+ else if (!(S_ISREG(*mode) || S_ISDIR(*mode) || S_ISLNK(*mode)))
+ ret = error(_("invalid '%s' mode: %o"), name, *mode);
+
+ return ret;
+}
+
+int cmd_merge_one_file(int argc, const char **argv, const char *prefix)
+{
+ struct object_id orig_blob, our_blob, their_blob,
+ *p_orig_blob = NULL, *p_our_blob = NULL, *p_their_blob = NULL;
+ unsigned int orig_mode = 0, our_mode = 0, their_mode = 0, ret = 0;
+ struct lock_file lock = LOCK_INIT;
+
+ if (argc != 8)
+ usage(builtin_merge_one_file_usage);
+
+ if (read_cache() < 0)
+ die("invalid index");
+
+ hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
+
+ if (!get_oid_hex(argv[1], &orig_blob)) {
+ p_orig_blob = &orig_blob;
+ ret = read_mode("orig", argv[5], &orig_mode);
+ } else if (!*argv[1] && *argv[5])
+ ret = error(_("no 'orig' object id given, but a mode was still given."));
+
+ if (!get_oid_hex(argv[2], &our_blob)) {
+ p_our_blob = &our_blob;
+ ret = read_mode("our", argv[6], &our_mode);
+ } else if (!*argv[2] && *argv[6])
+ ret = error(_("no 'our' object id given, but a mode was still given."));
+
+ if (!get_oid_hex(argv[3], &their_blob)) {
+ p_their_blob = &their_blob;
+ ret = read_mode("their", argv[7], &their_mode);
+ } else if (!*argv[3] && *argv[7])
+ ret = error(_("no 'their' object id given, but a mode was still given."));
+
+ if (ret)
+ return ret;
+
+ ret = merge_three_way(the_repository, p_orig_blob, p_our_blob, p_their_blob,
+ argv[4], orig_mode, our_mode, their_mode);
+
+ if (ret) {
+ rollback_lock_file(&lock);
+ return !!ret;
+ }
+
+ return write_locked_index(&the_index, &lock, COMMIT_LOCK);
+}
diff --git a/git-merge-one-file.sh b/git-merge-one-file.sh
deleted file mode 100755
index f6d9852d2f..0000000000
--- a/git-merge-one-file.sh
+++ /dev/null
@@ -1,167 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) Linus Torvalds, 2005
-#
-# This is the git per-file merge script, called with
-#
-# $1 - original file SHA1 (or empty)
-# $2 - file in branch1 SHA1 (or empty)
-# $3 - file in branch2 SHA1 (or empty)
-# $4 - pathname in repository
-# $5 - original file mode (or empty)
-# $6 - file in branch1 mode (or empty)
-# $7 - file in branch2 mode (or empty)
-#
-# Handle some trivial cases.. The _really_ trivial cases have
-# been handled already by git read-tree, but that one doesn't
-# do any merges that might change the tree layout.
-
-USAGE='<orig blob> <our blob> <their blob> <path>'
-USAGE="$USAGE <orig mode> <our mode> <their mode>"
-LONG_USAGE="usage: git merge-one-file $USAGE
-
-Blob ids and modes should be empty for missing files."
-
-SUBDIRECTORY_OK=Yes
-. git-sh-setup
-cd_to_toplevel
-require_work_tree
-
-if test $# != 7
-then
- echo "$LONG_USAGE"
- exit 1
-fi
-
-case "${1:-.}${2:-.}${3:-.}" in
-#
-# Deleted in both or deleted in one and unchanged in the other
-#
-"$1.." | "$1.$1" | "$1$1.")
- if { test -z "$6" && test "$5" != "$7"; } ||
- { test -z "$7" && test "$5" != "$6"; }
- then
- echo "ERROR: File $4 deleted on one branch but had its" >&2
- echo "ERROR: permissions changed on the other." >&2
- exit 1
- fi
-
- if test -n "$2"
- then
- echo "Removing $4"
- else
- # read-tree checked that index matches HEAD already,
- # so we know we do not have this path tracked.
- # there may be an unrelated working tree file here,
- # which we should just leave unmolested. Make sure
- # we do not have it in the index, though.
- exec git update-index --remove -- "$4"
- fi
- if test -f "$4"
- then
- rm -f -- "$4" &&
- rmdir -p "$(expr "z$4" : 'z\(.*\)/')" 2>/dev/null || :
- fi &&
- exec git update-index --remove -- "$4"
- ;;
-
-#
-# Added in one.
-#
-".$2.")
- # the other side did not add and we added so there is nothing
- # to be done, except making the path merged.
- exec git update-index --add --cacheinfo "$6" "$2" "$4"
- ;;
-"..$3")
- echo "Adding $4"
- if test -f "$4"
- then
- echo "ERROR: untracked $4 is overwritten by the merge." >&2
- exit 1
- fi
- git update-index --add --cacheinfo "$7" "$3" "$4" &&
- exec git checkout-index -u -f -- "$4"
- ;;
-
-#
-# Added in both, identically (check for same permissions).
-#
-".$3$2")
- if test "$6" != "$7"
- then
- echo "ERROR: File $4 added identically in both branches," >&2
- echo "ERROR: but permissions conflict $6->$7." >&2
- exit 1
- fi
- echo "Adding $4"
- git update-index --add --cacheinfo "$6" "$2" "$4" &&
- exec git checkout-index -u -f -- "$4"
- ;;
-
-#
-# Modified in both, but differently.
-#
-"$1$2$3" | ".$2$3")
-
- case ",$6,$7," in
- *,120000,*)
- echo "ERROR: $4: Not merging symbolic link changes." >&2
- exit 1
- ;;
- *,160000,*)
- echo "ERROR: $4: Not merging conflicting submodule changes." >&2
- exit 1
- ;;
- esac
-
- src1=$(git unpack-file $2)
- src2=$(git unpack-file $3)
- case "$1" in
- '')
- echo "Added $4 in both, but differently."
- orig=$(git unpack-file $(git hash-object /dev/null))
- ;;
- *)
- echo "Auto-merging $4"
- orig=$(git unpack-file $1)
- ;;
- esac
-
- git merge-file "$src1" "$orig" "$src2"
- ret=$?
- msg=
- if test $ret != 0 || test -z "$1"
- then
- msg='content conflict'
- ret=1
- fi
-
- # Create the working tree file, using "our tree" version from the
- # index, and then store the result of the merge.
- git checkout-index -f --stage=2 -- "$4" && cat "$src1" >"$4" || exit 1
- rm -f -- "$orig" "$src1" "$src2"
-
- if test "$6" != "$7"
- then
- if test -n "$msg"
- then
- msg="$msg, "
- fi
- msg="${msg}permissions conflict: $5->$6,$7"
- ret=1
- fi
-
- if test $ret != 0
- then
- echo "ERROR: $msg in $4" >&2
- exit 1
- fi
- exec git update-index -- "$4"
- ;;
-
-*)
- echo "ERROR: $4: Not handling case $1 -> $2 -> $3" >&2
- ;;
-esac
-exit 1
diff --git a/git.c b/git.c
index f1e8b56d99..a4d3f98094 100644
--- a/git.c
+++ b/git.c
@@ -540,6 +540,7 @@ static struct cmd_struct commands[] = {
{ "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
{ "merge-index", cmd_merge_index, RUN_SETUP | NO_PARSEOPT },
{ "merge-ours", cmd_merge_ours, RUN_SETUP | NO_PARSEOPT },
+ { "merge-one-file", cmd_merge_one_file, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
{ "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
{ "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
{ "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
diff --git a/merge-strategies.c b/merge-strategies.c
new file mode 100644
index 0000000000..c5576dc891
--- /dev/null
+++ b/merge-strategies.c
@@ -0,0 +1,176 @@
+#include "cache.h"
+#include "dir.h"
+#include "merge-strategies.h"
+#include "xdiff-interface.h"
+
+static int checkout_from_index(struct index_state *istate, const char *path,
+ struct cache_entry *ce)
+{
+ struct checkout state = CHECKOUT_INIT;
+
+ state.istate = istate;
+ state.force = 1;
+ state.base_dir = "";
+ state.base_dir_len = 0;
+
+ if (checkout_entry(ce, &state, NULL, NULL) < 0)
+ return error(_("%s: cannot checkout file"), path);
+ return 0;
+}
+
+static int merge_one_file_deleted(struct index_state *istate,
+ const struct object_id *our_blob,
+ const struct object_id *their_blob, const char *path,
+ unsigned int orig_mode, unsigned int our_mode, unsigned int their_mode)
+{
+ if ((our_blob && orig_mode != our_mode) ||
+ (their_blob && orig_mode != their_mode))
+ return error(_("File %s deleted on one branch but had its "
+ "permissions changed on the other."), path);
+
+ if (our_blob) {
+ printf(_("Removing %s\n"), path);
+
+ if (file_exists(path))
+ remove_path(path);
+ }
+
+ if (remove_file_from_index(istate, path))
+ return error("%s: cannot remove from the index", path);
+ return 0;
+}
+
+static int do_merge_one_file(struct index_state *istate,
+ const struct object_id *orig_blob,
+ const struct object_id *our_blob,
+ const struct object_id *their_blob, const char *path,
+ unsigned int orig_mode, unsigned int our_mode, unsigned int their_mode)
+{
+ int ret, i, dest;
+ ssize_t written;
+ mmbuffer_t result = {NULL, 0};
+ mmfile_t mmfs[3];
+ xmparam_t xmp = {{0}};
+
+ if (our_mode == S_IFLNK || their_mode == S_IFLNK)
+ return error(_("%s: Not merging symbolic link changes."), path);
+ else if (our_mode == S_IFGITLINK || their_mode == S_IFGITLINK)
+ return error(_("%s: Not merging conflicting submodule changes."), path);
+ else if (our_mode != their_mode)
+ return error(_("permission conflict: %o->%o,%o in %s"),
+ orig_mode, our_mode, their_mode, path);
+
+ if (orig_blob) {
+ printf(_("Auto-merging %s\n"), path);
+ read_mmblob(mmfs + 0, orig_blob);
+ } else {
+ printf(_("Added %s in both, but differently.\n"), path);
+ read_mmblob(mmfs + 0, &null_oid);
+ }
+
+ read_mmblob(mmfs + 1, our_blob);
+ read_mmblob(mmfs + 2, their_blob);
+
+ xmp.level = XDL_MERGE_ZEALOUS_ALNUM;
+ xmp.style = 0;
+ xmp.favor = 0;
+
+ ret = xdl_merge(mmfs + 0, mmfs + 1, mmfs + 2, &xmp, &result);
+
+ for (i = 0; i < 3; i++)
+ free(mmfs[i].ptr);
+
+ if (ret < 0) {
+ free(result.ptr);
+ return error(_("Failed to execute internal merge"));
+ } else if (ret > 0 || !orig_blob) {
+ free(result.ptr);
+ return error(_("content conflict in %s"), path);
+ }
+
+ unlink(path);
+ if ((dest = open(path, O_WRONLY | O_CREAT, our_mode)) < 0) {
+ free(result.ptr);
+ return error_errno(_("failed to open file '%s'"), path);
+ }
+
+ written = write_in_full(dest, result.ptr, result.size);
+ close(dest);
+
+ free(result.ptr);
+
+ if (written < 0)
+ return error_errno(_("failed to write to '%s'"), path);
+
+ return add_file_to_index(istate, path, 0);
+}
+
+int merge_three_way(struct repository *r,
+ const struct object_id *orig_blob,
+ const struct object_id *our_blob,
+ const struct object_id *their_blob, const char *path,
+ unsigned int orig_mode, unsigned int our_mode, unsigned int their_mode)
+{
+ if (orig_blob &&
+ ((!their_blob && our_blob && oideq(orig_blob, our_blob)) ||
+ (!our_blob && their_blob && oideq(orig_blob, their_blob)))) {
+ /* Deleted in both or deleted in one and unchanged in the other. */
+ return merge_one_file_deleted(r->index, our_blob, their_blob, path,
+ orig_mode, our_mode, their_mode);
+ } else if (!orig_blob && our_blob && !their_blob) {
+ /*
+ * Added in one. The other side did not add and we
+ * added so there is nothing to be done, except making
+ * the path merged.
+ */
+ return add_to_index_cacheinfo(r->index, our_mode, our_blob,
+ path, 0, 1, 1, NULL);
+ } else if (!orig_blob && !our_blob && their_blob) {
+ struct cache_entry *ce;
+ printf(_("Adding %s\n"), path);
+
+ if (file_exists(path))
+ return error(_("untracked %s is overwritten by the merge."), path);
+
+ if (add_to_index_cacheinfo(r->index, their_mode, their_blob,
+ path, 0, 1, 1, &ce))
+ return -1;
+ return checkout_from_index(r->index, path, ce);
+ } else if (!orig_blob && our_blob && their_blob &&
+ oideq(our_blob, their_blob)) {
+ struct cache_entry *ce;
+
+ /* Added in both, identically (check for same permissions). */
+ if (our_mode != their_mode)
+ return error(_("File %s added identically in both branches, "
+ "but permissions conflict %o->%o."),
+ path, our_mode, their_mode);
+
+ printf(_("Adding %s\n"), path);
+
+ if (add_to_index_cacheinfo(r->index, our_mode, our_blob,
+ path, 0, 1, 1, &ce))
+ return -1;
+ return checkout_from_index(r->index, path, ce);
+ } else if (our_blob && their_blob) {
+ /* Modified in both, but differently. */
+ return do_merge_one_file(r->index,
+ orig_blob, our_blob, their_blob, path,
+ orig_mode, our_mode, their_mode);
+ } else {
+ char orig_hex[GIT_MAX_HEXSZ] = {0}, our_hex[GIT_MAX_HEXSZ] = {0},
+ their_hex[GIT_MAX_HEXSZ] = {0};
+
+ if (orig_blob)
+ oid_to_hex_r(orig_hex, orig_blob);
+ if (our_blob)
+ oid_to_hex_r(our_hex, our_blob);
+ if (their_blob)
+ oid_to_hex_r(their_hex, their_blob);
+
+ return error(_("%s: Not handling case %s -> %s -> %s"),
+ path, orig_hex, our_hex, their_hex);
+ }
+
+ return 0;
+}
diff --git a/merge-strategies.h b/merge-strategies.h
new file mode 100644
index 0000000000..e624c4f27c
--- /dev/null
+++ b/merge-strategies.h
@@ -0,0 +1,12 @@
+#ifndef MERGE_STRATEGIES_H
+#define MERGE_STRATEGIES_H
+
+#include "object.h"
+
+int merge_three_way(struct repository *r,
+ const struct object_id *orig_blob,
+ const struct object_id *our_blob,
+ const struct object_id *their_blob, const char *path,
+ unsigned int orig_mode, unsigned int our_mode, unsigned int their_mode);
+
+#endif /* MERGE_STRATEGIES_H */
diff --git a/t/t6415-merge-dir-to-symlink.sh b/t/t6415-merge-dir-to-symlink.sh
index 2eddcc7664..5fb74e39a0 100755
--- a/t/t6415-merge-dir-to-symlink.sh
+++ b/t/t6415-merge-dir-to-symlink.sh
@@ -94,7 +94,7 @@ test_expect_success SYMLINKS 'a/b was resolved as symlink' '
test -h a/b
'
-test_expect_failure 'do not lose untracked in merge (resolve)' '
+test_expect_success 'do not lose untracked in merge (resolve)' '
git reset --hard &&
git checkout baseline^0 &&
>a/b/c/e &&
--
2.20.1
