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git grep broken in Fedora 21 update?

Subject: git grep broken in Fedora 21 update?

## tl;dr

5 messages between Sep 4, 2015 and Sep 4, 2015.

replies: 4people: 4as markdown or json

Rustad, Mark D· Sep 4, 2015, 00:04 UTC · lore

I just found a case where grep and git grep yield different results. Inside the ixgbe directory of the Linux kernel I did:

$ grep enter_lplu *.[ch]

And got the following:

ixgbe_main.c: if (adapter->hw.phy.ops.enter_lplu) { ixgbe_main.c: adapter->hw.phy.ops.enter_lplu(&adapter->hw); ixgbe_type.h: s32 (*enter_lplu)(struct ixgbe_hw *); ixgbe_x550.c:/** ixgbe_enter_lplu_x550em - Transition to low power states ixgbe_x550.c:static s32 ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw) ixgbe_x550.c: phy->ops.enter_lplu = ixgbe_enter_lplu_t_x550em;

But when I did:

$ git grep enter_lplu

I got:

You can see that git grep missed the line in ixgbe_x550.c that had two hits on the string.

This was with git 2.1.0 in Fedora 21. I use git grep a lot and never noticed a problem before. I just updated my Fedora 21 system yesterday, so I have to figure that has something to do with it. I checked and git didn't get updated, so I figure it must be a library that is really broken.

I see in my update log that pcre was updated to:

pcre.x86_64 0:8.35-12.fc21 pcre-devel.x86_64 0:8.35-12.fc21

Yet the grep command is unaffected.

-- Mark Rustad, Networking Division, Intel Corporation

Jacob Keller· Sep 4, 2015, 04:55 UTC · re: Rustad, Mark D · lore

Re: git grep broken in Fedora 21 update?

On Thu, Sep 3, 2015 at 5:04 PM, Rustad, Mark D <mark.d.rustad@intel.com> wrote:

Show 39 quoted lines

> I just found a case where grep and git grep yield different results. Inside the ixgbe directory of the Linux kernel I did:
>
> $ grep enter_lplu *.[ch]
>
> And got the following:
>
> ixgbe_main.c:   if (adapter->hw.phy.ops.enter_lplu) {
> ixgbe_main.c:           adapter->hw.phy.ops.enter_lplu(&adapter->hw);
> ixgbe_type.h:   s32 (*enter_lplu)(struct ixgbe_hw *);
> ixgbe_x550.c:/** ixgbe_enter_lplu_x550em - Transition to low power states
> ixgbe_x550.c:static s32 ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw)
> ixgbe_x550.c:                   phy->ops.enter_lplu = ixgbe_enter_lplu_t_x550em;
>
> But when I did:
>
> $ git grep enter_lplu
>
> I got:
>
> ixgbe_main.c:   if (adapter->hw.phy.ops.enter_lplu) {
> ixgbe_main.c:           adapter->hw.phy.ops.enter_lplu(&adapter->hw);
> ixgbe_type.h:   s32 (*enter_lplu)(struct ixgbe_hw *);
> ixgbe_x550.c:/** ixgbe_enter_lplu_x550em - Transition to low power states
> ixgbe_x550.c:static s32 ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw)
>
> You can see that git grep missed the line in ixgbe_x550.c that had two hits on the string.
>
> This was with git 2.1.0 in Fedora 21. I use git grep a lot and never noticed a problem before. I just updated my Fedora 21 system yesterday, so I have to figure that has something to do with it. I checked and git didn't get updated, so I figure it must be a library that is really broken.
>
> I see in my update log that pcre was updated to:
>
> pcre.x86_64 0:8.35-12.fc21
> pcre-devel.x86_64 0:8.35-12.fc21
>
> Yet the grep command is unaffected.
>
> --
> Mark Rustad, Networking Division, Intel Corporation
>

I don't know if command line grep uses pcre?

Does git-grep by default ignore changes not yet committed? That was my first thought but I am not very familiar with the tool.

Regards, Jake

Michael J Gruber· Sep 4, 2015, 13:34 UTC · re: Jacob Keller · lore

Re: git grep broken in Fedora 21 update?

Jacob Keller venit, vidit, dixit 04.09.2015 06:55:

Show 49 quoted lines

> On Thu, Sep 3, 2015 at 5:04 PM, Rustad, Mark D <mark.d.rustad@intel.com> wrote:
>> I just found a case where grep and git grep yield different results. Inside the ixgbe directory of the Linux kernel I did:
>>
>> $ grep enter_lplu *.[ch]
>>
>> And got the following:
>>
>> ixgbe_main.c:   if (adapter->hw.phy.ops.enter_lplu) {
>> ixgbe_main.c:           adapter->hw.phy.ops.enter_lplu(&adapter->hw);
>> ixgbe_type.h:   s32 (*enter_lplu)(struct ixgbe_hw *);
>> ixgbe_x550.c:/** ixgbe_enter_lplu_x550em - Transition to low power states
>> ixgbe_x550.c:static s32 ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw)
>> ixgbe_x550.c:                   phy->ops.enter_lplu = ixgbe_enter_lplu_t_x550em;
>>
>> But when I did:
>>
>> $ git grep enter_lplu
>>
>> I got:
>>
>> ixgbe_main.c:   if (adapter->hw.phy.ops.enter_lplu) {
>> ixgbe_main.c:           adapter->hw.phy.ops.enter_lplu(&adapter->hw);
>> ixgbe_type.h:   s32 (*enter_lplu)(struct ixgbe_hw *);
>> ixgbe_x550.c:/** ixgbe_enter_lplu_x550em - Transition to low power states
>> ixgbe_x550.c:static s32 ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw)
>>
>> You can see that git grep missed the line in ixgbe_x550.c that had two hits on the string.
>>
>> This was with git 2.1.0 in Fedora 21. I use git grep a lot and never noticed a problem before. I just updated my Fedora 21 system yesterday, so I have to figure that has something to do with it. I checked and git didn't get updated, so I figure it must be a library that is really broken.
>>
>> I see in my update log that pcre was updated to:
>>
>> pcre.x86_64 0:8.35-12.fc21
>> pcre-devel.x86_64 0:8.35-12.fc21
>>
>> Yet the grep command is unaffected.
>>
>> --
>> Mark Rustad, Networking Division, Intel Corporation
>>
> 
> I don't know if command line grep uses pcre?
> 
> Does git-grep by default ignore changes not yet committed? That was my
> first thought but I am not very familiar with the tool.
> 
> Regards,
> Jake
>

Can you downgrade pcre and check whether that's the reason?

Also, -14 in testing contains a few fixes.

Michael

Jeff King· Sep 4, 2015, 14:03 UTC · re: Rustad, Mark D · lore

Re: git grep broken in Fedora 21 update?

On Fri, Sep 04, 2015 at 12:04:38AM +0000, Rustad, Mark D wrote:

Show 14 quoted lines

> You can see that git grep missed the line in ixgbe_x550.c that had two hits on the string.
> 
> This was with git 2.1.0 in Fedora 21. I use git grep a lot and never
> noticed a problem before. I just updated my Fedora 21 system
> yesterday, so I have to figure that has something to do with it. I
> checked and git didn't get updated, so I figure it must be a library
> that is really broken.
> 
> I see in my update log that pcre was updated to:
> 
> pcre.x86_64 0:8.35-12.fc21
> pcre-devel.x86_64 0:8.35-12.fc21
> 
> Yet the grep command is unaffected.

I don't think "git grep" should be using pcre unless you specified "-P" on the command line (which might be an interesting experiment, to see if it improves the result).

It shouldn't be affected by your working tree state. "git grep" without arguments searches the working tree, just like grep. It might omit a file that is not tracked, but given that the missing line is from a file which _does_ have other results, that's clearly not the problem.

Is it possible that git _is_ producing the hit, but it is getting eaten by the pager or something like that? Does "git --no-pager grep enter_lplu" produce the same results?

I don't think there have been any git bugs in this area for quite a while. In your position I'd try building from source to see if a freshly built version has the same problem.

-Peff

Rustad, Mark D· Sep 4, 2015, 16:18 UTC · re: Jeff King · lore

Re: git grep broken in Fedora 21 update?

Show 5 quoted lines

> On Sep 4, 2015, at 7:03 AM, Jeff King <peff@peff.net> wrote:
> 
> Is it possible that git _is_ producing the hit, but it is getting eaten
> by the pager or something like that? Does "git --no-pager grep
> enter_lplu" produce the same results?

Well what do you know. Adding --no-pager gave me the right results. I wonder if the output isn't getting flushed to the pipe or something. In any case, I can add --no-pager to the alias I normally use and I'll be happy. The root cause will just gnaw at me for a while...

Hmm. Doing git grep enter_lplu | cat - also worked.

-- Mark Rustad, Networking Division, Intel Corporation