[StGit PATCH 5/5] Add "stg coalesce"

["Karl Hasselström" <kha@treskal.com>]

It coalesces two or more consecutive applied patches, with no need to
touch index/worktree, and no possibiliy of conflicts.

Future improvements could relax the "consecutive" and "applied"
restrictions, by building a new chain of commits just like "stg push"
will do once it's been converted to the new infrastructure.

Signed-off-by: Karl Hasselström <kha@treskal.com>

---

 stgit/commands/coalesce.py |   87 ++++++++++++++++++++++++++++++++++++++++++++
 stgit/main.py              |    2 +
 stgit/utils.py             |   11 ++++++
 t/t2600-coalesce.sh        |   31 ++++++++++++++++
 4 files changed, 131 insertions(+), 0 deletions(-)
 create mode 100644 stgit/commands/coalesce.py
 create mode 100755 t/t2600-coalesce.sh


diff --git a/stgit/commands/coalesce.py b/stgit/commands/coalesce.py
new file mode 100644
index 0000000..11b7b52
--- /dev/null
+++ b/stgit/commands/coalesce.py
@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+
+__copyright__ = """
+Copyright (C) 2007, Karl Hasselström <kha@treskal.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License version 2 as
+published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+"""
+
+from optparse import make_option
+from stgit.out import *
+from stgit import utils
+from stgit.commands import common
+from stgit.lib import git, transaction
+
+help = 'coalesce two or more patches into one'
+usage = """%prog [options] <patches>
+
+Coalesce two or more patches, creating one big patch that contains all
+their changes. The patches must all be applied, and must be
+consecutive."""
+
+directory = common.DirectoryHasRepositoryLib()
+options = [make_option('-n', '--name', help = 'name of coalesced patch'),
+           make_option('-m', '--message',
+                       help = 'commit message of coalesced patch')]
+
+def _coalesce(stack, name, msg, patches):
+    applied = stack.patchorder.applied
+
+    # Make sure the patches are consecutive.
+    applied_ix = dict((applied[i], i) for i in xrange(len(applied)))
+    ixes = list(sorted(applied_ix[p] for p in patches))
+    i0, i1 = ixes[0], ixes[-1]
+    if i1 - i0 + 1 != len(patches):
+        raise common.CmdException('The patches must be consecutive')
+
+    # Make a commit for the coalesced patch.
+    def bad_name(pn):
+        return pn not in patches and stack.patches.exists(pn)
+    if name and bad_name(name):
+        raise common.CmdException('Patch name "%s" already taken')
+    ps = [stack.patches.get(pn) for pn in applied[i0:i1+1]]
+    if msg == None:
+        msg = '\n\n'.join('%s\n\n%s' % (p.name.ljust(70, '-'),
+                                        p.commit.data.message)
+                          for p in ps)
+        msg = utils.edit_string(msg, '.stgit-coalesce.txt').strip()
+    if not name:
+        name = utils.make_patch_name(msg, bad_name)
+    cd = git.Commitdata(tree = ps[-1].commit.data.tree,
+                        parents = ps[0].commit.data.parents, message = msg)
+
+    # Rewrite refs.
+    trans = transaction.StackTransaction(stack, 'coalesce')
+    parent = trans.patches[name] = stack.repository.commit(cd)
+    trans.applied = applied[:i0]
+    trans.applied.append(name)
+    for pn in applied[i0:i1+1]:
+        trans.patches[pn] = None
+    for pn in applied[i1+1:]:
+        p = stack.patches.get(pn)
+        parent = trans.patches[pn] = stack.repository.commit(
+            p.commit.data.set_parent(parent))
+        trans.applied.append(pn)
+    trans.run()
+
+def func(parser, options, args):
+    stack = directory.repository.current_stack
+    applied = set(stack.patchorder.applied)
+    for pn in args:
+        if not pn in applied:
+            raise common.CmdException('%s is not applied' % pn)
+    patches = set(args)
+    if len(patches) < 2:
+        raise common.CmdException('Need at least two patches')
+    _coalesce(stack, options.name, options.message, args)
diff --git a/stgit/main.py b/stgit/main.py
index 9ef6d44..ac46cde 100644
--- a/stgit/main.py
+++ b/stgit/main.py
@@ -65,6 +65,7 @@ commands = Commands({
     'diff':             'diff',
     'clean':            'clean',
     'clone':            'clone',
+    'coalesce':         'coalesce',
     'commit':           'commit',
     'edit':             'edit',
     'export':           'export',
@@ -109,6 +110,7 @@ stackcommands = (
     'assimilate',
     'branch',
     'clean',
+    'coalesce',
     'commit',
     'float',
     'goto',
diff --git a/stgit/utils.py b/stgit/utils.py
index b3f6232..688276c 100644
--- a/stgit/utils.py
+++ b/stgit/utils.py
@@ -189,6 +189,17 @@ def call_editor(filename):
         raise EditorException, 'editor failed, exit code: %d' % err
     out.done()
 
+def edit_string(s, filename):
+    f = file(filename, 'w')
+    f.write(s)
+    f.close()
+    call_editor(filename)
+    f = file(filename)
+    s = f.read()
+    f.close()
+    os.remove(filename)
+    return s
+
 def patch_name_from_msg(msg):
     """Return a string to be used as a patch name. This is generated
     from the top line of the string passed as argument."""
diff --git a/t/t2600-coalesce.sh b/t/t2600-coalesce.sh
new file mode 100755
index 0000000..f13a309
--- /dev/null
+++ b/t/t2600-coalesce.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+test_description='Run "stg coalesce"'
+
+. ./test-lib.sh
+
+test_expect_success 'Initialize StGit stack' '
+    stg init &&
+    for i in 0 1 2 3; do
+        stg new p$i -m "foo $i" &&
+        echo "foo $i" >> foo.txt &&
+        git add foo.txt &&
+        stg refresh
+    done
+'
+
+test_expect_success 'Coalesce some patches' '
+    [ "$(echo $(stg applied))" = "p0 p1 p2 p3" ] &&
+    [ "$(echo $(stg unapplied))" = "" ] &&
+    stg coalesce --name=q0 --message="wee woo" p1 p2 &&
+    [ "$(echo $(stg applied))" = "p0 q0 p3" ] &&
+    [ "$(echo $(stg unapplied))" = "" ]
+'
+
+test_expect_success 'Coalesce at stack top' '
+    stg coalesce --name=q1 --message="wee woo wham" q0 p3 &&
+    [ "$(echo $(stg applied))" = "p0 q1" ] &&
+    [ "$(echo $(stg unapplied))" = "" ]
+'
+
+test_done