Git: discover which commits ever touched a range of lines
I'm having trouble figuring out how to use git blame for getting the set of commits that ever touched a given range of lines. There are similar questions like this one but the accepted answer doesn't bring me much further.
Let's say I have a definition that starts on line 1000 of foo.rb. It's only only 5 lines long, but the number of commits that ever changed those lines is enormous. If I do
git blame foo.rb -L 1000,+5
I get references to (at most) five distinct commits that changed these lines, but I'm also interested in the commits "behind them".
Similarly,
git rev-list HEAD -- foo.rb | xargs git log --oneline
is almost what I want, but I can't specify line ranges to git rev-list
Can I pass a flag to git blame to get the list of commits that ever touched those five lines, or what's the quickest way to build a script that extracts such information? Let's ignore for the moment the possibility that the definition once had more or less than 5 lines.
Answer
Since Git 1.8.4, git log has -L to view the evolution of a range of lines.
For example, suppose you look at git blame's output:
((aa27064...))[mlm@macbook:~/w/mlm/git]
$ git blame -L150,+11 -- git-web--browse.sh
a180055a git-web--browse.sh (Giuseppe Bilotta 2010-12-03 17:47:36 +0100 150) die "The browser $browser is not
a180055a git-web--browse.sh (Giuseppe Bilotta 2010-12-03 17:47:36 +0100 151) fi
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 152) fi
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 153)
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 154) case "$browser" in
81f42f11 git-web--browse.sh (Giuseppe Bilotta 2010-12-03 17:47:38 +0100 155) firefox|iceweasel|seamonkey|iceape)
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 156) # Check version because firefox < 2.0 do
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 157) vers=$(expr "$($browser_path -version)"
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 158) NEWTAB='-new-tab'
5d6491c7 git-browse-help.sh (Christian Couder 2007-12-02 06:07:55 +0100 159) test "$vers" -lt 2 && NEWTAB=''
a0685a4f git-web--browse.sh (Dmitry Potapov 2008-02-09 23:22:22 -0800 160) "$browser_path" $NEWTAB "$@" &
And you want to know the history of what is now line 155.
Then:
((aa27064...))[mlm@macbook:~/w/mlm/git]
$ git log --topo-order --graph -u -L 155,155:git-web--browse.sh
* commit 81f42f11496b9117273939c98d270af273c8a463
| Author: Giuseppe Bilotta <[email protected]>
| Date: Fri Dec 3 17:47:38 2010 +0100
|
| web--browse: support opera, seamonkey and elinks
|
| The list of supported browsers is also updated in the documentation.
|
| Signed-off-by: Giuseppe Bilotta <[email protected]>
| Signed-off-by: Junio C Hamano <[email protected]>
|
| diff --git a/git-web--browse.sh b/git-web--browse.sh
| --- a/git-web--browse.sh
| +++ b/git-web--browse.sh
| @@ -143,1 +143,1 @@
| -firefox|iceweasel)
| +firefox|iceweasel|seamonkey|iceape)
|
* commit a180055a47c6793eaaba6289f623cff32644215b
| Author: Giuseppe Bilotta <[email protected]>
| Date: Fri Dec 3 17:47:36 2010 +0100
|
| web--browse: coding style
|
| Retab and deindent choices in case statements.
|
| Signed-off-by: Giuseppe Bilotta <[email protected]>
| Signed-off-by: Junio C Hamano <[email protected]>
|
| diff --git a/git-web--browse.sh b/git-web--browse.sh
| --- a/git-web--browse.sh
| +++ b/git-web--browse.sh
| @@ -142,1 +142,1 @@
| - firefox|iceweasel)
| +firefox|iceweasel)
|
* commit 5884f1fe96b33d9666a78e660042b1e3e5f9f4d9
Author: Christian Couder <[email protected]>
Date: Sat Feb 2 07:32:53 2008 +0100
Rename 'git-help--browse.sh' to 'git-web--browse.sh'.
Signed-off-by: Christian Couder <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
diff --git a/git-web--browse.sh b/git-web--browse.sh
--- /dev/null
+++ b/git-web--browse.sh
@@ -0,0 +127,1 @@
+ firefox|iceweasel)
If you use this functionality frequently, you might find a git alias useful. To do that, put in your ~/.gitconfig:
[alias]
# Follow evolution of certain lines in a file
# arg1=file, arg2=first line, arg3=last line or blank for just the first line
follow = "!sh -c 'git log --topo-order -u -L $2,${3:-$2}:"$1"'" -
And now you can just do git follow git-web--browse.sh 155.