Re: [PATCH] difftool: add support for an extended revision syntax

> Documentation/git-difftool.txt | 55 ++++++++++++++++++- > git-difftool.perl | 119 ++++++++++++++++++++++++++++++++++++++-- > t/t7800-difftool.sh | 43 ++++++++++++++ > 3 files changed, 210 insertions(+), 7 deletions(-) > > diff --git a/Documentation/git-difftool.txt b/Documentation/git-difftool.txt > index 5ae02f8..2911b84 100644 > --- a/Documentation/git-difftool.txt > +++ b/Documentation/git-difftool.txt > @@ -7,7 +7,9 @@ git-difftool - Show changes using common diff tools > > SYNOPSIS > -------- > -'git difftool' [--tool=<tool>] [--no-prompt] [<'git diff' options>] > +'git difftool' [--tool=<tool>] [--no-prompt] > + [<'git diff' options>] > + [<extended revision syntax>] > > DESCRIPTION > ----------- > @@ -54,6 +56,57 @@ with custom merge tool commands and has the same value as `$LOCAL`. > > See linkgit:git-diff[1] for the full list of supported options. > > +EXTENDED REVISION SYNTAX > +------------------------ > +'git-difftool' understands an extended syntax for specifying revisions. > + > +* A suffix '{tilde}' to a file means the previous commit that touched file. > + > +* A suffix '{tilde}<n>' to a file means the <n>th previous commit that > +touched file. E.g. 'file\~3' is equivalent to 'file\~\~\~'. > + > +* A revision suffixed with an exclamation mark '!' expands to > +'revision\~..revision', i.e. the commit diff for that revision. > + > +'git-difftool' recognizes this syntax and passes the corresponding > +commits to 'git-diff'. > + > +Examples > +~~~~~~~~ > + > +--------------------------------------------------- > +# File Revision Specifiers > +$ git difftool Makefile~2 <1> > +$ git difftool Makefile~4 Makefile~2 <2> > +$ git difftool Makefile~~~~ Makefile~~ <3> > + > +# Commit Diff Specifiers > +$ git difftool origin/next~! <4> > +$ git difftool HEAD! <5> > +$ git difftool ! <6> > +--------------------------------------------------- > + > +<1> compare 'Makefile' in the worktree against 'Makefile' > +as it existed two `versions` ago. `Versions` here means > +"changes to Makefile" such that only commits that touch > +'Makefile' are considered when finding commits. > + > +<2> compare 'Makefile' as it existed four versions ago to > +'Makefile' as it existed two versions ago. > + > +<3> equivalent to example 2 and illustrates what happens when > +multiple '{tilde}' characters are used. > + > +<4> show the commit diff for 'origin/next\~'. > +Specifying '!' expands 'origin/next\~' to > +'origin/next\~\~..origin/next\~'. > + > +<5> show the commit diff for the most recent commit. > +'HEAD!' is equivalent to 'HEAD\~..HEAD'. > + > +<6> '!' is a shorthand for 'HEAD!' and is equivalent to example 5. > + > + > CONFIG VARIABLES > ---------------- > 'git-difftool' falls back to 'git-mergetool' config variables when the > diff --git a/git-difftool.perl b/git-difftool.perl > index 0deda3a..4845f9b 100755 > --- a/git-difftool.perl > +++ b/git-difftool.perl > @@ -12,13 +12,17 @@ use warnings; > use Cwd qw(abs_path); > use File::Basename qw(dirname); > > +binmode(STDOUT, ":raw"); > + > my $DIR = abs_path(dirname(__PLACEHOLDER__1_)); > > > sub usage > { > print << 'USAGE'; > -usage: git difftool [--tool=<tool>] [--no-prompt] ["git diff" options] > +usage: git difftool [--tool=<tool>] [--no-prompt] > + [<'git diff' options>] > + [<extended revision specifier>] > USAGE > exit 1; > } > @@ -33,12 +37,18 @@ sub setup_environment > sub exe > { > my $exe = shift; > - return defined $ENV{COMSPEC} ? "$exe.exe" : $exe; > + if ($^O eq 'MSWin32' || $^O eq 'msys') { > + return "$exe.exe"; > + } > + return $exe; > } > > sub generate_command > { > + # Generate a git-diff command line and set environment > + # variables recognized by git-difftool-helper > my @command = (exe('git'), 'diff'); > + my @args = (); > my $skip_next = 0; > my $idx = -1; > for my $arg (@ARGV) { > @@ -47,7 +57,7 @@ sub generate_command > $skip_next = 0; > next; > } > - if ($arg eq '-t' or $arg eq '--tool') { > + if ($arg eq '-t' || $arg eq '--tool') { > usage() if $#ARGV <= $idx; > $ENV{GIT_DIFF_TOOL} = $ARGV[$idx + 1]; > $skip_next = 1; > @@ -61,12 +71,109 @@ sub generate_command > $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true'; > next; > } > - if ($arg eq '-h' or $arg eq '--help') { > + if ($arg eq '-h' || $arg eq '--help') { > usage(); > } > - push @command, $arg; > + push @args, $arg; > + } > + return (@command, interpolate_args(@args)); > +} > + > + > +sub interpolate_args > +{ > + # Interpolates arguments that should be expanded out to > + # corresponding commits, e.g. 'file~3' or 'master!'. > + my @args = @_; > + my $file = undef; > + my @command = (); > + for my $arg (@args) { > + if (defined $file && $arg eq $file) { > + # This allows 'git difftool file~ file' > + next; > + } > + if ($arg =~ /^(.+?)(~+\d*)$/) { > + # This arg might be a file-revision specifier > + my $cur_file = ; > + my $rev_spec = ; > + if (defined $file && $file ne $cur_file) { > + # We don't currently support comparing > + # file~ to other_file~ > + usage(); > + } > + if (!-e $cur_file) { > + # This arg is a revision parameter and should > + # be passed along to git-diff as-is > + push @command, $arg; > + next; > + } > + # This arg is a file-revision specifier so find the > + # corresponding commits > + $file = $cur_file; > + push @command, > + find_commit_for_file($cur_file, $rev_spec); > + } > + elsif ($arg =~ /^(.*?)!$/) { > + # Expand 'sha1!' to 'sha1~ sha1' > + my $head = ; > + if (length($head) == 0) { > + # Expand '!' to 'HEAD~ HEAD' > + $head = 'HEAD'; > + } > + push @command, $head.'~'; > + push @command, $head; > + } > + else { > + # This is a regular arg so just pass it along > + push @command, $arg; > + } > + } > + if (defined $file) { > + # We're using a 'file~' revision specifier so > + # automatically limit git-diff to just a single file > + $ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true'; > + push @command, '--', $file; > + } > + return @command; > +} > + > +sub find_commit_for_file > +{ > + # Searches back in $file's history according to $rev_spec > + # and finds the corresponding commits. > + # $rev_spec usually looks like '~' or '~2'. > + my ($file, $rev_spec) = @_; > + my $num = 0; > + if ($rev_spec =~ /^(~+)(\d+)$/) { > + $num = length(); > + $num += ; > + } > + else { > + $num = 1; > + $num += length($rev_spec); > + } > + my @cmd = (exe('git'), 'log'); > + my @opts = ('--reverse', '--pretty=format:%H', '--max-count='.$num); > + my @args = ('--', $file); > + return read_first_line(@cmd, @opts, @args); > +} > + > +sub read_first_line > +{ > + # Runs a command in a child process and returns the first line > + my @command = @_; > + my $pid = open(CHILD, '-|'); > + if ($pid) { > + # Grab the first line and loop over stdout until we're done > + my $line = <CHILD>; > + while(<CHILD>) {}; > + close(CHILD); > + chomp $line; > + return $line; > + } else { > + # Execute the command and pipe output to our parent > + exec(@command) or exit 1; > } > - return @command > } > > setup_environment(); > diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh > index c7cd2b1..88af30a 100755 > --- a/t/t7800-difftool.sh > +++ b/t/t7800-difftool.sh > @@ -136,4 +136,47 @@ test_expect_success 'difftool + mergetool config variables' ' > restore_test_defaults > ' > > +test_expect_success 'extended file revision syntax' ' > + git checkout branch && > + > + diff=$(git difftool file~) && > + test "$diff" = "master" && > + > + diff=$(git difftool file~ file) && > + test "$diff" = "master" && > + > + echo branch 2 >file && > + git commit -a -m "branch changes again" && > + > + diff=$(git difftool file~~ file) && > + test "$diff" = "master" && > + > + diff=$(git difftool file~2 file) && > + test "$diff" = "master" && > + > + git reset --hard HEAD~ && > + git checkout master > +' > + > +test_expect_success 'extended commit-ish revision syntax' ' > + git checkout branch && > + > + diff=$(git difftool --no-prompt HEAD!) && > + test "$diff" = "master" && > + > + diff=$(git difftool --no-prompt !) && > + test "$diff" = "master" && > + > + echo branch again >file && > + git commit -a -m "branch again" && > + git checkout master && > + > + diff=$(git difftool --no-prompt branch!) && > + test "$diff" = "branch" && > + > + git checkout branch && > + git reset --hard HEAD~ && > + git checkout master > +' > + > test_done


linux-kernel:
Greg KH	Og dreams of kernels
Jens Axboe	[PATCH 31/33] Fusion: sg chaining support
Arnd Bergmann	Re: finding your own dead "CONFIG_" variables
Mark Brown	[PATCH 2/2] Subject: natsemi: Allow users to disable workaround for DspCfg reset
Tony Breeds	[LGUEST] Look in object dir for .config
git:
Brian Downing	Re: Git in a Nutshell guide
John Benes	Re: master has some toys
Matthias Lederhofer	[PATCH 4/7] introduce GIT_WORK_TREE to specify the work tree
Alexander Sulfrian	[RFC/PATCH] RE: git calls SSH_ASKPASS even if DISPLAY is not set
Junio C Hamano	Re: Rss produced by git is not valid xml?
git-commits-head:
Linux Kernel Mailing List	iSeries: fix section mismatch in iseries_veth
Linux Kernel Mailing List	ixbge: remove TX lock and redo TX accounting.
Linux Kernel Mailing List	ixgbe: fix several counter register errata