git-cvsexportcommit.perl

   1 #!/usr/bin/perl -w
   2
   3 # Known limitations:
   4 # - cannot add or remove binary files
   5 # - cannot add parent directories when needed
   6 # - does not propagate permissions
   7 # - tells "ready for commit" even when things could not be completed
   8 #   (eg addition of a binary file)
   9
  10 use strict;
  11 use Getopt::Std;
  12 use File::Temp qw(tempdir);
  13 use Data::Dumper;
  14 use File::Basename qw(basename);
  15
  16 unless ($ENV{GIT_DIR} && -r $ENV{GIT_DIR}){
  17     die "GIT_DIR is not defined or is unreadable";
  18 }
  19
  20 our ($opt_h, $opt_p, $opt_v, $opt_c, $opt_f, $opt_m );
  21
  22 getopts('hpvcfm:');
  23
  24 $opt_h && usage();
  25
  26 die "Need at least one commit identifier!" unless @ARGV;
  27
  28 # setup a tempdir
  29 our ($tmpdir, $tmpdirname) = tempdir('git-cvsapplycommit-XXXXXX',
  30                                      TMPDIR => 1,
  31                                      CLEANUP => 1);
  32
  33 print Dumper(@ARGV);
  34 # resolve target commit
  35 my $commit;
  36 $commit = pop @ARGV;
  37 $commit = safe_pipe_capture('git-rev-parse', '--verify', "$commit^0");
  38 chomp $commit;
  39 if ($?) {
  40     die "The commit reference $commit did not resolve!";
  41 }
  42
  43 # resolve what parent we want
  44 my $parent;
  45 if (@ARGV) {
  46     $parent = pop @ARGV;
  47     $parent =  safe_pipe_capture('git-rev-parse', '--verify', "$parent^0");
  48     chomp $parent;
  49     if ($?) {
  50         die "The parent reference did not resolve!";
  51     }
  52 }
  53
  54 # find parents from the commit itself
  55 my @commit  = safe_pipe_capture('git-cat-file', 'commit', $commit);
  56 my @parents;
  57 foreach my $p (@commit) {
  58     if ($p =~ m/^$/) { # end of commit headers, we're done
  59         last;
  60     }
  61     if ($p =~ m/^parent (\w{40})$/) { # found a parent
  62         push @parents, $1;
  63     }
  64 }
  65
  66 if ($parent) {
  67     # double check that it's a valid parent
  68     foreach my $p (@parents) {
  69         my $found;
  70         if ($p eq $parent) {
  71             $found = 1;
  72             last;
  73         }; # found it
  74         die "Did not find $parent in the parents for this commit!";
  75     }
  76 } else { # we don't have a parent from the cmdline...
  77     if (@parents == 1) { # it's safe to get it from the commit
  78         $parent = $parents[0];
  79     } else { # or perhaps not!
  80         die "This commit has more than one parent -- please name the parent you want to use explicitly";
  81     }
  82 }
  83
  84 $opt_v && print "Applying to CVS commit $commit from parent $parent\n";
  85
  86 # grab the commit message
  87 open(MSG, ">.msg") or die "Cannot open .msg for writing";
  88 print MSG $opt_m;
  89 close MSG;
  90
  91 `git-cat-file commit $commit | sed -e '1,/^\$/d' >> .msg`;
  92 $? && die "Error extracting the commit message";
  93
  94 my (@afiles, @dfiles, @mfiles);
  95 my @files = safe_pipe_capture('git-diff-tree', '-r', $parent, $commit);
  96 #print @files;
  97 $? && die "Error in git-diff-tree";
  98 foreach my $f (@files) {
  99     chomp $f;
 100     my @fields = split(m!\s+!, $f);
 101     if ($fields[4] eq 'A') {
 102         push @afiles, $fields[5];
 103     }
 104     if ($fields[4] eq 'M') {
 105         push @mfiles, $fields[5];
 106     }
 107     if ($fields[4] eq 'R') {
 108         push @dfiles, $fields[5];
 109     }
 110 }
 111 $opt_v && print "The commit affects:\n ";
 112 $opt_v && print join ("\n ", @afiles,@mfiles,@dfiles) . "\n\n";
 113 undef @files; # don't need it anymore
 114
 115 # check that the files are clean and up to date according to cvs
 116 my $dirty;
 117 foreach my $f (@afiles) {
 118     # This should return only one value
 119     my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 120     if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 121     unless ($status[0] =~ m/Status: Unknown$/) {
 122         $dirty = 1;
 123         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";
 124     }
 125 }
 126 foreach my $f (@mfiles, @dfiles) {
 127     # TODO:we need to handle removed in cvs
 128     my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 129     if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 130     unless ($status[0] =~ m/Status: Up-to-date$/) {
 131         $dirty = 1;
 132         warn "File $f not up to date in your CVS checkout!\n";
 133     }
 134 }
 135 if ($dirty) {
 136     if ($opt_f) {       warn "The tree is not clean -- forced merge\n";
 137         $dirty = 0;
 138     } else {
 139         die "Exiting: your CVS tree is not clean for this merge.";
 140     }
 141 }
 142
 143 ###
 144 ### NOTE: if you are planning to die() past this point
 145 ###       you MUST call cleanupcvs(@files) before die()
 146 ###
 147
 148
 149 print "'Patching' binary files\n";
 150
 151 my @bfiles = grep(m/^Binary/, safe_pipe_capture('git-diff-tree', '-p', $parent, $commit));
 152 @bfiles = map { chomp } @bfiles;
 153 foreach my $f (@bfiles) {
 154     # check that the file in cvs matches the "old" file
 155     # extract the file to $tmpdir and comparre with cmp
 156     my $tree = safe_pipe_capture('git-rev-parse', "$parent^{tree}");
 157     chomp $tree;
 158     my $blob = `git-ls-tree $tree "$f" | cut -f 1 | cut -d ' ' -f 3`;
 159     chomp $blob;
 160     `git-cat-file blob $blob > $tmpdir/blob`;
 161     if (system('cmp', '-s', $f, "$tmpdir/blob")) {
 162         warn "Binary file $f in CVS does not match parent.\n";
 163         $dirty = 1;
 164         next;
 165     }
 166
 167     # replace with the new file
 168      `git-cat-file blob $blob > $f`;
 169
 170     # TODO: something smart with file modes
 171
 172 }
 173 if ($dirty) {
 174     cleanupcvs(@files);
 175     die "Exiting: Binary files in CVS do not match parent";
 176 }
 177
 178 ## apply non-binary changes
 179 my $fuzz = $opt_p ? 0 : 2;
 180
 181 print "Patching non-binary files\n";
 182 print `(git-diff-tree -p $parent -p $commit | patch -p1 -F $fuzz ) 2>&1`;
 183
 184 my $dirtypatch = 0;
 185 if (($? >> 8) == 2) {
 186     cleanupcvs(@files);
 187     die "Exiting: Patch reported serious trouble -- you will have to apply this patch manually";
 188 } elsif (($? >> 8) == 1) { # some hunks failed to apply
 189     $dirtypatch = 1;
 190 }
 191
 192 foreach my $f (@afiles) {
 193     system('cvs', 'add', $f);
 194     if ($?) {
 195         $dirty = 1;
 196         warn "Failed to cvs add $f -- you may need to do it manually";
 197     }
 198 }
 199
 200 foreach my $f (@dfiles) {
 201     system('cvs', 'rm', '-f', $f);
 202     if ($?) {
 203         $dirty = 1;
 204         warn "Failed to cvs rm -f $f -- you may need to do it manually";
 205     }
 206 }
 207
 208 print "Commit to CVS\n";
 209 my $commitfiles = join(' ', @afiles, @mfiles, @dfiles);
 210 my $cmd = "cvs commit -F .msg $commitfiles";
 211
 212 if ($dirtypatch) {
 213     print "NOTE: One or more hunks failed to apply cleanly.\n";
 214     print "Resolve the conflicts and then commit using:\n";
 215     print "\n    $cmd\n\n";
 216     exit(1);
 217 }
 218
 219
 220 if ($opt_c) {
 221     print "Autocommit\n  $cmd\n";
 222     print safe_pipe_capture('cvs', 'commit', '-F', '.msg', @afiles, @mfiles, @dfiles);
 223     if ($?) {
 224         cleanupcvs(@files);
 225         die "Exiting: The commit did not succeed";
 226     }
 227     print "Committed successfully to CVS\n";
 228 } else {
 229     print "Ready for you to commit, just run:\n\n   $cmd\n";
 230 }
 231 sub usage {
 232         print STDERR <<END;
 233 Usage: GIT_DIR=/path/to/.git ${\basename $0} [-h] [-p] [-v] [-c] [-f] [-m msgprefix] [ parent ] commit
 234 END
 235         exit(1);
 236 }
 237
 238 # ensure cvs is clean before we die
 239 sub cleanupcvs {
 240     my @files = @_;
 241     foreach my $f (@files) {
 242         system('cvs', '-q', 'update', '-C', $f);
 243         if ($?) {
 244             warn "Warning! Failed to cleanup state of $f\n";
 245         }
 246     }
 247 }
 248
 249 # An alterative to `command` that allows input to be passed as an array
 250 # to work around shell problems with weird characters in arguments
 251 # if the exec returns non-zero we die
 252 sub safe_pipe_capture {
 253     my @output;
 254     if (my $pid = open my $child, '-|') {
 255         @output = (<$child>);
 256         close $child or die join(' ',@_).": $! $?";
 257     } else {
 258         exec(@_) or die "$! $?"; # exec() can fail the executable can't be found
 259     }
 260     return wantarray ? @output : join('',@output);
 261 }