[Vm-dev] git bites again

[Eliot Miranda]

Hi Jakob, Hi Fabio,

On Tue, Feb 20, 2018 at 11:43 PM, Fabio Niephaus <lists at fniephaus.com>
wrote:

>
> Hi all,
>
> On Wed, Feb 21, 2018 at 8:17 AM Alistair Grant <akgrant0710 at gmail.com>
> wrote:
>
>>
>> Hi Tim & Eliot,
>>
>> On 21 February 2018 at 04:11, Eliot Miranda <eliot.miranda at gmail.com>
>> wrote:
>> >
>> > Hi Tim,
>> >
>> > On Tue, Feb 20, 2018 at 6:29 PM, tim Rowledge <tim at rowledge.org> wrote:
>> >>
>> >>
>> >> OK, I know that the entire point of git is to drive people insane but
>> this is an especially silly problem.
>> >>
>> >> clone the repository with
>> >> git clone https://github.com/OpenSmalltalk/opensmalltalk-vm.git
>> >> wait...
>> >> cd opensmalltalk-vm/
>> >> ./scripts/updateSCCSVersions ->
>> >> fatal: Not a git repository: '.git'
>> >> fatal: unrecognized input
>> >>
>> >> What?
>>
>
> As part of the transition from SVN to Git, we had to add a script that
> runs after certain Git commands and inserts a timestamp into the code which
> is then compiled into the VM as a part of its version string. This approach
> does not only sound hacky, it actually is hacky, but a Git commit hash was
> not good enough. Unfortunately, there are many ways to work with Git
> repositories (e.g. submodules), so Jakob proposed a change that seemed to
> fix things for some use cases while apparently breaking things for other
> users.
>
>
>> >> The annoying part is that it worked (at least, so far as I remember)
>> last time I loaded up a clone of the vm repo.
>>
>
> I've reverted Jakob's change, so please try again.
>

Thanks.  It's good to know what the change is :-).

So we're talking about this change, right? :

diff --git a/scripts/updateSCCSVersions b/scripts/updateSCCSVersions
index 179b008..8593f2f 100755
--- a/scripts/updateSCCSVersions
+++ b/scripts/updateSCCSVersions
@@ -3,15 +3,13 @@
 # platforms/Cross/vm/sqSCCSVersion.h to be checked-in so that its version
 # info reflects that of the current check-in.

-if [ -d `dirname $0`/../.git ]; then
-       hooks_dir="`git rev-parse --git-dir`/hooks"
-    mkdir -p $hooks_dir
-    cp -f $0 $hooks_dir/post-commit
-    cp -f $0 $hooks_dir/post-merge
-    cp -f $0 $hooks_dir/post-checkout
-    cd `dirname $0`/..
+if [ "$(cd "$(dirname $0)" && git rev-parse --is-inside-git-dir)" = false
]; then
+    hooks_dir="`git rev-parse --git-dir`/hooks"
+    mkdir -p "$hooks_dir"
+    cp -f "$0" "$hooks_dir/post-commit"
+    cp -f "$0" "$hooks_dir/post-merge"
+    cp -f "$0" "$hooks_dir/post-checkout"
 else
-    cd `dirname $0`/../..
     if [[ "$(basename $0)" == "post-checkout" ]]; then
         prevHEAD=$1
         newHEAD=$2

Jakob, my understanding is that in shell if one wants to evaluate something
enc capture its output one must use backpacks.  e.g. using the dirname $0
example above one can say either `dirname $0` or "`dirname $0`", the
difference being that the first can expand to multiple tokens but the last
will be considered a single then.  I don't understand what the intent of
"$(cd "$(dirname $0)" && git rev-parse --is-inside-git-dir)" = false is.
But in any case if "$(cd "$(dirname $0)" did work the same as "`cd
\`dirname $0\` `", it would;t have the desired effect because the command
is evaluated in a sub-shell and hence doesn't change the working directory
for the git rev-parse --is-inside-git-dir command.  I think you need to say
something like

if (cd `dirname $0`; git rev-parse --is-inside-git-dir); then

This evaluates the cd in a sub-shell established by the parentheses, and
hence also changes the current directory for the git rev-parse
--is-inside-git-dir command.  Since "if" takes a command ( /bin/[ is merely
a link to /bin/test ) one doesn't need the sub-shell evaluation and can run
the git command directly.  If we were in the right directory then we could
write

if git rev-parse --is-inside-git-dir; then

The next issue is to get rid of the "fatal: not a git directory" output.
You can redirect stderr to /dev/null.  hence what I *think* you want to
write is

if (cd `dirname $0`; git rev-parse --is-inside-git-dir 2>/dev/null); then

HTH

And Jakob, I hope you're not offended!  The request to revert was not in
any way a criticism of you.  We all make mistakes and often those who make
most mistakes are contributing the most.


> Agreed.  It is incumbent upon whoever made the change to fix this.  "you
>> break it, you fix it".  so please, step up :-)
>> >
>> > _,,,^..^,,,_
>> > best, Eliot
>> >
>>
>> The offending commit is 0458c6a92651fc8d0bf86158a0407f87470ade50 from
>> 6 Feb.  I'm not familiar enough with git to easily fix it, but backing
>> out the change should be straightforward.
>>
>
> Thanks for looking into this, Alistair.
>
>
>>
>> Cheers,
>> Alistair
>>
>

_,,,^..^,,,_
best, Eliot
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