Re: [Qemu-devel] [RFC PATCH qemu] git-submodule.sh: Do not try writing to source directory if not necessary

[Alexey Kardashevskiy]

On 25/10/17 17:57, Daniel P. Berrange wrote:
> On Wed, Oct 25, 2017 at 12:45:10PM +1100, Alexey Kardashevskiy wrote:
>> On 25/10/17 03:27, Daniel P. Berrange wrote:
>>> On Tue, Oct 24, 2017 at 07:58:53PM +1100, Alexey Kardashevskiy wrote:
>>>> The new git-submodule.sh script writes .git-submodule-status to
>>>> the source directory every time no matter what. This makes it conditional.
>>>>
>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>>> ---
>>>>
>>>> I compile out of tree on a remote guest system where I mount the
>>>> source directory as "readonly" and build directory as "rw" and
>>>> scripts/git-submodule.sh tries writing to the source directory even when
>>>> I manually update modules on a host machine which is quite annoying.
>>>>
>>>> Is this something acceptable? Or I am missing something here?
>>>
>>> How did you update the modules - did you manually run  'git submodule 
>>> update...'
>>> or did you use the git-submodule.sh script on your host machine ?
>>
>>
>> I run scripts/git-submodule.sh. Which is not thrilling either as I rather
>> expect source tree not to be affected in any way when running "make".
> 
> Oh, did you pass the list of sub-modules to it when running
> 
> eg, ./scripts/git-submodule.sh update ui/keycodemapdb
> 
> the list of submodules you need is printed in the configure output summary.

Sure, otherwise it does nothing.


> 
>>> If you run git-submodule.sh on the host, then it should save the status
>>> file, and then when you run make on the guest system, it should notice
>>> that you're already updated and never even invoke 'git-submodule.sh update'
>>
>>
>> scripts/git-submodule.sh also tries writing to the source directory (I
>> should probably have fixed that branch too) but this failure is not fatal
>> for "make" but makes it want to try "update" and then "make" fails.
> 
> This shouldn't have happened in your case though, if you have already run
> 'git-submodule.sh update ...list of modules...' on the host machine, with
> the same list of modules that the guest 'configure' printed out.

It does not matter if I run git-submodule.sh or not - "git-submodule.sh
status" will try writing to the read only folder anyway and it will fail
and Makefile's  git_module_status will be set to 1.

If I do as below (and that's what I should have done as I said), then
"git-submodule.sh update" is not invoked and we are good. I am not
reposting it yet as 1) my shell skills are crap (need to delete the temp
file or rewrite the whole thing not to use temp file or rewrite it in
python - why do not people use python everywhere?!) 2) I still hope we stop
doing this from Makefile :)



diff --git a/scripts/git-submodule.sh b/scripts/git-submodule.sh
index d8fbc7e47e..ced00b6cae 100755
--- a/scripts/git-submodule.sh
+++ b/scripts/git-submodule.sh
@@ -23,16 +23,20 @@ then
     exit 1
 fi

+substat_tmp=$(mktemp)
+
 case "$command" in
 status)
     test -f "$substat" || exit 1
-    trap "rm -f ${substat}.tmp" EXIT
-    git submodule status $modules > "${substat}.tmp"
-    diff "${substat}" "${substat}.tmp" >/dev/null
+    git submodule status $modules > "$substat_tmp"
+    diff "${substat_tmp}" "${substat}" || mv "${substat_tmp}" "${substat}"
+    ( rm "${substat_tmp}" 2>/dev/null )
     exit $?
     ;;
 update)
     git submodule update --init $modules 1>/dev/null 2>&1
-    git submodule status $modules > "${substat}"
+    git submodule status $modules > "$substat_tmp"
+    diff "${substat_tmp}" "${substat}" || mv "${substat_tmp}" "${substat}"
+    ( rm "${substat_tmp}" 2>/dev/null )
     ;;
 esac



-- 
Alexey