[PATCH 4/4] Makefile change and merge-trees script itself.
Show changes to diff +303 −1
Index: Makefile
===================================================================
--- 6767883b330882bc0e9a7c1e4fd999c0ee97ba3a/Makefile (mode:100644 sha1:3a4683454df4ac8f16eca01fe93a787a2ce8f0f4)
+++ 21e5e9f7d7dfa81c6519f0204d5a467236c7fdd5/Makefile (mode:100644 sha1:0384a229456145a763a5316ce301e74d07454f66)
@@ -19,7 +19,7 @@
SCRIPT= parent-id tree-id git gitXnormid.sh gitadd.sh gitaddremote.sh \
gitcommit.sh gitdiff-do gitdiff.sh gitlog.sh gitls.sh gitlsobj.sh \
gitmerge.sh gitpull.sh gitrm.sh gittag.sh gittrack.sh gitexport.sh \
- gitapply.sh gitcancel.sh gitlntree.sh commit-id
+ gitapply.sh gitcancel.sh gitlntree.sh commit-id merge-trees
COMMON= read-cache.o
Index: merge-trees
===================================================================
--- /dev/null (tree:6767883b330882bc0e9a7c1e4fd999c0ee97ba3a)
+++ 21e5e9f7d7dfa81c6519f0204d5a467236c7fdd5/merge-trees (mode:100775 sha1:5da2f8a949aeffa60a400d013222fce34eb7262e)
@@ -0,0 +1,302 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Cwd;
+use Getopt::Long;
+
+my $full_checkout = 0;
+my $partial_checkout = 0;
+my $output_directory = ',,merge~tree';
+
+GetOptions("full-checkout" => \$full_checkout,
+ "partial-checkout" => \$partial_checkout,
+ "output-directory=s" => \$output_directory)
+ or die;
+
+
+if (@ARGV != 3) {
+ die "Usage: $0 -o [output-directory] [-f] [-p] ancestor A B\n";
+}
+
+if ($full_checkout) {
+ $partial_checkout = 1;
+}
+
+################################################################
+# UI helper -- although it is encouraged to give tree ID,
+# it is OK to give commit ID.
+sub possibly_commit_to_tree {
+ my ($commit_or_tree_id) = @_;
+ my $type = read_cat_file_t($commit_or_tree_id);
+ if ($type eq 'tree') { return $commit_or_tree_id }
+ if ($type ne 'commit') {
+ die "Tree ID (or commit ID) required, given $type.";
+ }
+
+ my ($fhi);
+ open $fhi, '-|', 'cat-file', 'commit', $commit_or_tree_id
+ or die "$!: cat-file commit $commit_or_tree_id";
+ my ($tree) = <$fhi>;
+ close $fhi;
+ ($tree =~ s/^tree (.*)$/$1/)
+ or die "$tree: Linus says the first line is guaranteed to be tree.";
+ return $tree;
+}
+
+sub read_cat_file_t {
+ my ($id) = @_;
+ my ($fhi);
+ open $fhi, '-|', 'cat-file', '-t', $id
+ or die "$!: cat-file -t $id";
+ my ($t) = <$fhi>;
+ close $fhi;
+ chomp($t);
+ return $t;
+}
+
+################################################################
+# Reads diff-tree -r output and gives a hash that maps a path
+# to 4-tuple (old-mode new-mode old-oid new-oid).
+# When creating, old-* are undef. When removing, new-* are undef.
+
+sub OLD_MODE () { 0 }
+sub NEW_MODE () { 1 }
+sub OLD_OID () { 2 }
+sub NEW_OID () { 3 }
+
+sub read_diff_tree {
+ my (@tree) = @_;
+ my ($fhi);
+
+ # Regular expression piece for mode
+ my $reM = '[0-7]+';
+
+ # Regular expression piece for object ID.
+ # There is a talk about base-64 so better make it easier to modify...
+ my $reID = '[0-9a-f]{40}';
+
+ local ($_, $/);
+ $/ = "\0";
+ my %path;
+ open $fhi, '-|', 'diff-tree', '-r', @tree
+ or die "$!: diff-tree -r @tree";
+ while (<$fhi>) {
+ chomp;
+ if (/^\*($reM)->($reM)\tblob\t($reID)->($reID)\t(.*)$/so) {
+ $path{$5} = [$1, $2, $3, $4]; # modified
+ }
+ elsif (/^\+($reM)\tblob\t($reID)\t(.*)$/so) {
+ $path{$3} = [undef, $1, undef, $2]; # added
+ }
+ elsif (/^\-($reM)\tblob\t($reID)\t(.*)$/so) {
+ $path{$3} = [$1, undef, $2, undef]; # deleted
+ }
+ else {
+ die "cannot parse diff-tree output: $_";
+ }
+ }
+ close $fhi;
+ return %path;
+}
+
+################################################################
+# Read show-files output to figure out the set of files contained
+# in the tree. This is used to figure out what ancestor had.
+sub read_show_files {
+ my ($fhi);
+ local ($_, $/);
+ $/ = "\0";
+ open $fhi, '-|', 'show-files', '-z', '--cached'
+ or die "$!: show-files -z --cached";
+ my (@path) = map { chomp; $_ } <$fhi>;
+ close $fhi;
+ return @path;
+}
+
+################################################################
+# Given path and info (typically returned from read_diff_tree),
+# create the file in the working directory to match the NEW tree.
+# This does not touch dircache.
+sub checkout_file {
+ my ($path, $info) = @_;
+ my (@elt) = split(/\//, $path);
+ my $j = '';
+ my $tail = pop @elt;
+ my ($fhi, $fho);
+ for (@elt) {
+ mkdir "$j$_";
+ $j = "$j$_/";
+ }
+ open $fho, '>', "$path";
+ open $fhi, '-|', 'cat-file', 'blob', $info->[NEW_OID]
+ or die "$!: cat-file blob $info->[NEW_OID]";
+ while (<$fhi>) {
+ print $fho $_;
+ }
+ close $fhi;
+ close $fho;
+ chmod oct("0$info->[NEW_MODE]"), "$path";
+}
+
+################################################################
+# Given path and info record the file in the dircache without
+# affecting working directory.
+sub record_file {
+ my ($path, $info) = @_;
+ system ('update-cache', '--add', '--cacheinfo',
+ $info->[NEW_MODE], $info->[NEW_OID], $path);
+}
+
+################################################################
+# Merge info from two trees and leave it in path, without
+# affecting dircache.
+sub merge_tree {
+ my ($path, $infoA, $infoB) = @_;
+ checkout_file("$path~A~", $infoA);
+ checkout_file("$path~B~", $infoB);
+ system 'checkout-cache', $path;
+ rename $path, "$path~O~";
+ my ($fhi, $fho);
+ open $fhi, '-|', 'merge', '-p', "$path~A~", "$path~O~", "$path~B~";
+ open $fho, '>', $path;
+ local ($/);
+ while (<$fhi>) { print $fho $_; }
+ close $fhi;
+ close $fho;
+ # There is no reason to prefer infoA over infoB but
+ # we need to pick one.
+ chmod oct("0$infoA->[NEW_MODE]"), $path;
+}
+
+################################################################
+
+# O stands for "the original". A and B are being merged.
+my ($treeO, $treeA, $treeB) = map { possibly_commit_to_tree $_ } @ARGV;
+
+# Create a temporary directory and go there.
+system('rm', '-rf', $output_directory) == 0 &&
+system('mkdir', '-p', "$output_directory/.git") == 0 &&
+symlink(Cwd::getcwd . "/.git/objects", "$output_directory/.git/objects") &&
+chdir $output_directory &&
+system('read-tree', $treeO) == 0
+ or die "$!: Failed to set up merge working area $output_directory";
+
+# Find out edits done in each branch.
+my %treeA = read_diff_tree($treeO, $treeA);
+my %treeB = read_diff_tree($treeO, $treeB);
+
+# The list of files that was in the ancestor.
+my @ancestor_file = read_show_files();
+my %ancestor_file = map { $_ => 1 } @ancestor_file;
+
+# Report output is formated as follows:
+#
+# The first letter shows the origin of the result.
+# O - original
+# A - treeA
+# B - treeB
+# M - both treeA and treeB
+# * - treeA and treeB conflicts; needs human action.
+#
+# The second and third letter shows what each tree did.
+# . - no change
+# A - created
+# M - modified
+# D - deleted
+
+for (@ancestor_file) {
+ if (! exists $treeA{$_} && ! exists $treeB{$_}) {
+ if ($full_checkout) {
+ system 'checkout-cache', $_;
+ }
+ print STDERR "O.. $_\n"; # keep original
+ }
+}
+
+for my $set ([\%treeA, \%treeB, 'A'], [\%treeB, \%treeA, 'B']) {
+ my ($this, $other, $side) = @$set;
+ my $delete_sign = ($side eq 'A') ? 'D.' : '.D';
+ my $create_sign = ($side eq 'A') ? 'A.' : '.A';
+ my $modify_sign = ($side eq 'A') ? 'M.' : '.M';
+ while (my ($path, $info) = each %$this) {
+ # In this loop we do not deal with overlaps.
+ next if (exists $other->{$path});
+
+ if (! defined $info->[NEW_OID]) {
+ # deleted in this tree only.
+ unlink $path;
+ system 'update-cache', '--remove', $path;
+ print STDERR "${side}${delete_sign} $path\n";
+ }
+ else {
+ # modified or created in this tree only.
+ my $create_or_modify =
+ (! defined $info->[OLD_OID]) ? $create_sign : $modify_sign;
+ print STDERR "${side}${create_or_modify} $path\n";
+ if ($partial_checkout) {
+ checkout_file($path, $info);
+ system 'update-cache', '--add', $path;
+ } else {
+ record_file($path, $info);
+ }
+ }
+ }
+}
+
+my @warning = ();
+
+while (my ($path, $infoA) = each %treeA) {
+ # We need to deal only with overlaps.
+ next if (!exists $treeB{$path});
+
+ my $infoB = $treeB{$path};
+ if (! defined $infoA->[NEW_OID]) {
+ # Deleted in tree A.
+ if (! defined $infoB->[NEW_OID]) {
+ # Deleted in both trees (obvious).
+ print STDERR "MDD $path\n";
+ unlink $path;
+ system 'update-cache', '--remove', $path;
+ }
+ else {
+ # TreeA wants to remove but TreeB wants to modify it.
+ print STDERR "*DM $path\n";
+ checkout_file("$path~B~", $infoB);
+ push @warning, $path;
+ }
+ }
+ else {
+ # Modified or created in tree A
+ if (! defined $infoB->[NEW_OID]) {
+ # TreeA wants to modify but treeB wants to remove it.
+ print STDERR "*MD $path\n";
+ checkout_file("$path~A~", $infoA);
+ push @warning, $path;
+ }
+ else {
+ # Modified both in treeA and treeB.
+ # Are they modifying to the same contents?
+ if ($infoA->[NEW_OID] eq $infoB->[NEW_OID]) {
+ # No changes or just the mode.
+ # we prefer TreeA over TreeB for no particular reason.
+ print STDERR "MMM $path\n";
+ record_file($path, $infoA);
+ }
+ else {
+ # Modified in both. Needs merge.
+ print STDERR "*MM $path\n";
+ merge_tree($path, $infoA, $infoB);
+ }
+ }
+ }
+}
+
+if (@warning) {
+ print "\nThere are some files that were deleted in one branch and\n"
+ . "modified in another. Please examine them carefully:\n";
+ for (@warning) {
+ print "$_\n";
+ }
+}
+
+# system 'show-diff', '-q';
Junio C Hamano