filter-branch: introduce convenience function "skip_commit"

With this function, a commit filter can leave out unwanted commits
(such as temporary commits).  It does _not_ undo the changeset
corresponding to that commit, but it _skips_ the revision.  IOW
no tree object is changed by this.

If you like to commit early and often, but want to filter out all
intermediate commits, marked by "@@@" in the commit message, you can
now do this with

git filter-branch --commit-filter '
if git cat-file commit $GIT_COMMIT | grep '@@@' > /dev/null;
then
skip_commit "$@";
else
git commit-tree "$@";
fi' newbranch

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index 456d52bb2490ded4552bb3ea2a00e30d27b73770..29bb8cec0c34709ef0fab7523be3b0b43c4c43c7 100644 (file)
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -112,6 +112,11 @@ OPTIONS
 As a special extension, the commit filter may emit multiple
 commit ids; in that case, ancestors of the original commit will
 have all of them as parents.
 As a special extension, the commit filter may emit multiple
 commit ids; in that case, ancestors of the original commit will
 have all of them as parents.

++
+You can use the 'map' convenience function in this filter, and other
+convenience functions, too.  For example, calling 'skip_commit "$@"'
+will leave out the current commit (but not its changes! If you want
+that, use gitlink:git-rebase[1] instead).

 
 --tag-name-filter <command>::
        This is the filter for rewriting tag names. When passed,
 
 --tag-name-filter <command>::
        This is the filter for rewriting tag names. When passed,


@@ -209,24 +214,39 @@ To remove commits authored by "Darl McBribe" from the history:
 git filter-branch --commit-filter '
        if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ];
        then
 git filter-branch --commit-filter '
        if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ];
        then

-               shift;
-               while [ -n "$1" ];
-               do
-                       shift;
-                       echo "$1";
-                       shift;
-               done;
+               skip_commit "$@";

        else
                git commit-tree "$@";
        fi' HEAD
 ------------------------------------------------------------------------------
 
        else
                git commit-tree "$@";
        fi' HEAD
 ------------------------------------------------------------------------------
 

+Note that the changes introduced by the commits, and not reverted by
+subsequent commits, will still be in the rewritten branch. If you want
+to throw out _changes_ together with the commits, you should use the
+interactive mode of gitlink:git-rebase[1].
+
+The function 'skip_commits' is defined as follows:
+
+--------------------------
+skip_commit()
+{
+       shift;
+       while [ -n "$1" ];
+       do
+               shift;
+               map "$1";
+               shift;
+       done;
+}
+--------------------------
+

 The shift magic first throws away the tree id and then the -p
 parameters.  Note that this handles merges properly! In case Darl
 committed a merge between P1 and P2, it will be propagated properly
 and all children of the merge will become merge commits with P1,P2
 as their parents instead of the merge commit.
 
 The shift magic first throws away the tree id and then the -p
 parameters.  Note that this handles merges properly! In case Darl
 committed a merge between P1 and P2, it will be propagated properly
 and all children of the merge will become merge commits with P1,P2
 as their parents instead of the merge commit.
 

+

 To restrict rewriting to only part of the history, specify a revision
 range in addition to the new branch name.  The new branch name will
 point to the top-most revision that a 'git rev-list' of this range
 To restrict rewriting to only part of the history, specify a revision
 range in addition to the new branch name.  The new branch name will
 point to the top-most revision that a 'git rev-list' of this range

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 3b041d81efd7e96a49c40eba0e23fc0b18508c82..a4b6577bd496819232754c1275b7c1e798b0470c 100755 (executable)
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -23,6 +23,20 @@ map()
        fi
 }
 
        fi
 }
 

+# if you run 'skip_commit "$@"' in a commit filter, it will print
+# the (mapped) parents, effectively skipping the commit.
+
+skip_commit()
+{
+       shift;
+       while [ -n "$1" ];
+       do
+               shift;
+               map "$1";
+               shift;
+       done;
+}
+

 # override die(): this version puts in an extra line break, so that
 # the progress is still visible
 
 # override die(): this version puts in an extra line break, so that
 # the progress is still visible
 

diff --git a/t/t7003-filter-branch.sh b/t/t7003-filter-branch.sh
index c79853d986ab31da6813576fe003f8a5885e0b64..e935b2000ac6589a4940f585616f8bf3be95223b 100755 (executable)
--- a/t/t7003-filter-branch.sh
+++ b/t/t7003-filter-branch.sh
@@ -138,13 +138,7 @@ test_expect_success "remove a certain author's commits" '
        git-filter-branch -f --commit-filter "\
                if [ \"\$GIT_AUTHOR_NAME\" = \"B V Uips\" ];\
                then\
        git-filter-branch -f --commit-filter "\
                if [ \"\$GIT_AUTHOR_NAME\" = \"B V Uips\" ];\
                then\

-                       shift;\
-                       while [ -n \"\$1\" ];\
-                       do\
-                               shift;\
-                               echo \"\$1\";\
-                               shift;\
-                       done;\
+                       skip_commit \"\$@\";

                else\
                        git commit-tree \"\$@\";\
                fi" removed-author &&
                else\
                        git commit-tree \"\$@\";\
                fi" removed-author &&