git-cvsexportcommit.perl

   1 #!/usr/bin/perl -w
   2
   3 # Known limitations:
   4 # - cannot add or remove binary files
   5 # - does not propagate permissions
   6 # - tells "ready for commit" even when things could not be completed
   7 #   (eg addition of a binary file)
   8
   9 use strict;
  10 use Getopt::Std;
  11 use File::Temp qw(tempdir);
  12 use Data::Dumper;
  13 use File::Basename qw(basename dirname);
  14
  15 unless ($ENV{GIT_DIR} && -r $ENV{GIT_DIR}){
  16     die "GIT_DIR is not defined or is unreadable";
  17 }
  18
  19 our ($opt_h, $opt_p, $opt_v, $opt_c, $opt_f, $opt_a, $opt_m );
  20
  21 getopts('hpvcfam:');
  22
  23 $opt_h && usage();
  24
  25 die "Need at least one commit identifier!" unless @ARGV;
  26
  27 # setup a tempdir
  28 our ($tmpdir, $tmpdirname) = tempdir('git-cvsapplycommit-XXXXXX',
  29                                      TMPDIR => 1,
  30                                      CLEANUP => 1);
  31
  32 # resolve target commit
  33 my $commit;
  34 $commit = pop @ARGV;
  35 $commit = safe_pipe_capture('git-rev-parse', '--verify', "$commit^0");
  36 chomp $commit;
  37 if ($?) {
  38     die "The commit reference $commit did not resolve!";
  39 }
  40
  41 # resolve what parent we want
  42 my $parent;
  43 if (@ARGV) {
  44     $parent = pop @ARGV;
  45     $parent =  safe_pipe_capture('git-rev-parse', '--verify', "$parent^0");
  46     chomp $parent;
  47     if ($?) {
  48         die "The parent reference did not resolve!";
  49     }
  50 }
  51
  52 # find parents from the commit itself
  53 my @commit  = safe_pipe_capture('git-cat-file', 'commit', $commit);
  54 my @parents;
  55 my $committer;
  56 my $author;
  57 my $stage = 'headers'; # headers, msg
  58 my $title;
  59 my $msg = '';
  60
  61 foreach my $line (@commit) {
  62     chomp $line;
  63     if ($stage eq 'headers' && $line eq '') {
  64         $stage = 'msg';
  65         next;
  66     }
  67
  68     if ($stage eq 'headers') {
  69         if ($line =~ m/^parent (\w{40})$/) { # found a parent
  70             push @parents, $1;
  71         } elsif ($line =~ m/^author (.+) \d+ \+\d+$/) {
  72             $author = $1;
  73         } elsif ($line =~ m/^committer (.+) \d+ \+\d+$/) {
  74             $committer = $1;
  75         }
  76     } else {
  77         $msg .= $line . "\n";
  78         unless ($title) {
  79             $title = $line;
  80         }
  81     }
  82 }
  83
  84 if ($parent) {
  85     my $found;
  86     # double check that it's a valid parent
  87     foreach my $p (@parents) {
  88         if ($p eq $parent) {
  89             $found = 1;
  90             last;
  91         }; # found it
  92     }
  93     die "Did not find $parent in the parents for this commit!" if !$found;
  94 } else { # we don't have a parent from the cmdline...
  95     if (@parents == 1) { # it's safe to get it from the commit
  96         $parent = $parents[0];
  97     } else { # or perhaps not!
  98         die "This commit has more than one parent -- please name the parent you want to use explicitly";
  99     }
 100 }
 101
 102 $opt_v && print "Applying to CVS commit $commit from parent $parent\n";
 103
 104 # grab the commit message
 105 open(MSG, ">.msg") or die "Cannot open .msg for writing";
 106 if ($opt_m) {
 107     print MSG $opt_m;
 108 }
 109 print MSG $msg;
 110 if ($opt_a) {
 111     print MSG "\n\nAuthor: $author\n";
 112     if ($author ne $committer) {
 113         print MSG "Committer: $committer\n";
 114     }
 115 }
 116 close MSG;
 117
 118 my (@afiles, @dfiles, @mfiles, @dirs);
 119 my @files = safe_pipe_capture('git-diff-tree', '-r', $parent, $commit);
 120 #print @files;
 121 $? && die "Error in git-diff-tree";
 122 foreach my $f (@files) {
 123     chomp $f;
 124     my @fields = split(m!\s+!, $f);
 125     if ($fields[4] eq 'A') {
 126         my $path = $fields[5];
 127         push @afiles, $path;
 128         # add any needed parent directories
 129         $path = dirname $path;
 130         while (!-d $path and ! grep { $_ eq $path } @dirs) {
 131             unshift @dirs, $path;
 132             $path = dirname $path;
 133         }
 134     }
 135     if ($fields[4] eq 'M') {
 136         push @mfiles, $fields[5];
 137     }
 138     if ($fields[4] eq 'D') {
 139         push @dfiles, $fields[5];
 140     }
 141 }
 142 $opt_v && print "The commit affects:\n ";
 143 $opt_v && print join ("\n ", @afiles,@mfiles,@dfiles) . "\n\n";
 144 undef @files; # don't need it anymore
 145
 146 # check that the files are clean and up to date according to cvs
 147 my $dirty;
 148 foreach my $d (@dirs) {
 149     if (-e $d) {
 150         $dirty = 1;
 151         warn "$d exists and is not a directory!\n";
 152     }
 153 }
 154 foreach my $f (@afiles) {
 155     # This should return only one value
 156     my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 157     if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 158     if (-d dirname $f and $status[0] !~ m/Status: Unknown$/
 159         and $status[0] !~ m/^File: no file /) {
 160         $dirty = 1;
 161         warn "File $f is already known in your CVS checkout -- perhaps it has been added by another user. Or this may indicate that it exists on a different branch. If this is the case, use -f to force the merge.\n";
 162         warn "Status was: $status[0]\n";
 163     }
 164 }
 165 foreach my $f (@mfiles, @dfiles) {
 166     # TODO:we need to handle removed in cvs
 167     my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 168     if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 169     unless ($status[0] =~ m/Status: Up-to-date$/) {
 170         $dirty = 1;
 171         warn "File $f not up to date in your CVS checkout!\n";
 172     }
 173 }
 174 if ($dirty) {
 175     if ($opt_f) {       warn "The tree is not clean -- forced merge\n";
 176         $dirty = 0;
 177     } else {
 178         die "Exiting: your CVS tree is not clean for this merge.";
 179     }
 180 }
 181
 182 ###
 183 ### NOTE: if you are planning to die() past this point
 184 ###       you MUST call cleanupcvs(@files) before die()
 185 ###
 186
 187
 188 print "Creating new directories\n";
 189 foreach my $d (@dirs) {
 190     unless (mkdir $d) {
 191         warn "Could not mkdir $d: $!";
 192         $dirty = 1;
 193     }
 194     `cvs add $d`;
 195     if ($?) {
 196         $dirty = 1;
 197         warn "Failed to cvs add directory $d -- you may need to do it manually";
 198     }
 199 }
 200
 201 print "'Patching' binary files\n";
 202
 203 my @bfiles = grep(m/^Binary/, safe_pipe_capture('git-diff-tree', '-p', $parent, $commit));
 204 @bfiles = map { chomp } @bfiles;
 205 foreach my $f (@bfiles) {
 206     # check that the file in cvs matches the "old" file
 207     # extract the file to $tmpdir and compare with cmp
 208     my $tree = safe_pipe_capture('git-rev-parse', "$parent^{tree}");
 209     chomp $tree;
 210     my $blob = `git-ls-tree $tree "$f" | cut -f 1 | cut -d ' ' -f 3`;
 211     chomp $blob;
 212     `git-cat-file blob $blob > $tmpdir/blob`;
 213     if (system('cmp', '-s', $f, "$tmpdir/blob")) {
 214         warn "Binary file $f in CVS does not match parent.\n";
 215         $dirty = 1;
 216         next;
 217     }
 218
 219     # replace with the new file
 220      `git-cat-file blob $blob > $f`;
 221
 222     # TODO: something smart with file modes
 223
 224 }
 225 if ($dirty) {
 226     cleanupcvs(@files);
 227     die "Exiting: Binary files in CVS do not match parent";
 228 }
 229
 230 ## apply non-binary changes
 231 my $fuzz = $opt_p ? 0 : 2;
 232
 233 print "Patching non-binary files\n";
 234 print `(git-diff-tree -p $parent -p $commit | patch -p1 -F $fuzz ) 2>&1`;
 235
 236 my $dirtypatch = 0;
 237 if (($? >> 8) == 2) {
 238     cleanupcvs(@files);
 239     die "Exiting: Patch reported serious trouble -- you will have to apply this patch manually";
 240 } elsif (($? >> 8) == 1) { # some hunks failed to apply
 241     $dirtypatch = 1;
 242 }
 243
 244 foreach my $f (@afiles) {
 245     system('cvs', 'add', $f);
 246     if ($?) {
 247         $dirty = 1;
 248         warn "Failed to cvs add $f -- you may need to do it manually";
 249     }
 250 }
 251
 252 foreach my $f (@dfiles) {
 253     system('cvs', 'rm', '-f', $f);
 254     if ($?) {
 255         $dirty = 1;
 256         warn "Failed to cvs rm -f $f -- you may need to do it manually";
 257     }
 258 }
 259
 260 print "Commit to CVS\n";
 261 print "Patch: $title\n";
 262 my $commitfiles = join(' ', @afiles, @mfiles, @dfiles);
 263 my $cmd = "cvs commit -F .msg $commitfiles";
 264
 265 if ($dirtypatch) {
 266     print "NOTE: One or more hunks failed to apply cleanly.\n";
 267     print "Resolve the conflicts and then commit using:\n";
 268     print "\n    $cmd\n\n";
 269     exit(1);
 270 }
 271
 272
 273 if ($opt_c) {
 274     print "Autocommit\n  $cmd\n";
 275     print safe_pipe_capture('cvs', 'commit', '-F', '.msg', @afiles, @mfiles, @dfiles);
 276     if ($?) {
 277         cleanupcvs(@files);
 278         die "Exiting: The commit did not succeed";
 279     }
 280     print "Committed successfully to CVS\n";
 281 } else {
 282     print "Ready for you to commit, just run:\n\n   $cmd\n";
 283 }
 284 sub usage {
 285         print STDERR <<END;
 286 Usage: GIT_DIR=/path/to/.git ${\basename $0} [-h] [-p] [-v] [-c] [-f] [-m msgprefix] [ parent ] commit
 287 END
 288         exit(1);
 289 }
 290
 291 # ensure cvs is clean before we die
 292 sub cleanupcvs {
 293     my @files = @_;
 294     foreach my $f (@files) {
 295         system('cvs', '-q', 'update', '-C', $f);
 296         if ($?) {
 297             warn "Warning! Failed to cleanup state of $f\n";
 298         }
 299     }
 300 }
 301
 302 # An alternative to `command` that allows input to be passed as an array
 303 # to work around shell problems with weird characters in arguments
 304 # if the exec returns non-zero we die
 305 sub safe_pipe_capture {
 306     my @output;
 307     if (my $pid = open my $child, '-|') {
 308         @output = (<$child>);
 309         close $child or die join(' ',@_).": $! $?";
 310     } else {
 311         exec(@_) or die "$! $?"; # exec() can fail the executable can't be found
 312     }
 313     return wantarray ? @output : join('',@output);
 314 }