#178 parsing of pretty=format:"%an %ad" causes fatal: bad revision '%ad'

Hi,

I’m very new to ‘git’ github. I reported the #178 issue in github and the issue has been closed, I believe this means no further discussion.

There are a three additional comments, thank you to the contributors. The advise was to discuss upstream which meant nothing to me (again thanks to another contributor for clarification).

Summary ------------ The issue reported is (in my opinion) a defect in argument processing (happens on Windows and Linux (as per another contributor)).

The issue (in my opinion) is a defect for argument processing by Git. The decision (agreement or otherwise) I guess is for this upstream discussion.

I appreciate the open-source git and its usage to the community. But this is owned by the discussion group and I doubt my involvement is wanted. So this will be my last communication on this issue.

Context ---------- Over many years, I’ve used command-line on Unix/Linux/Windows in both hobby and professional modes. In the latter case the processing of arguments with spaces has often been the cause of defects (none expected behaviour) for newly introduced products.

I’ve found no documentation about the pretty=format behaviour as described by the #178 issue. Also, there are many (but incomplete) google-it second-hand documents(?) about. So a document fix in the internet age is not necessarily the approach to solve an issue, as all those google-it items create fog.

For this issue I was processing a git command to run in a GUI and happened upon it. The GUI (original design by me) allows interfacing with CVS, SVN, HG and maybe now GIT in a similar manner. The GUI holds the interfacing and access information and concatenates it onto the VCS command/sub-commands as appropriate for a request. Thus, the concatenated VCS request may be processed for copy-paste onto a command line window/terminal or (for my GUI) executed via a programming language’s command-line-execution class/function (Perl, Java, C,.....).

With the argument being further processed within git, it behaves in a manner that wasn’t expected.

Thx Dave

the Issue as reported

Getting a fatal failure when using the following --pretty=format:"%an %ad" via a programmed execution from within a programming language. (Java using the execution capabilities puts the ' --pretty=format:"%an %ad" ' as an argument). This is reproduced on a Windows command-line entry by putting double-quotes around the argument. (see below for various examples of pass, fail and testing around).

The git argument parser appears to perform a split on spaces within the arguments passed to it also. This is not a normal behaviour for any parsing. Also, the split is happening within a string quote, it would appear ("%an %ad"). Even tried %20 to represent the space.

Thx

G:\ws_test_env\GIT_TESTBED_TMP\fest-swing-1.x>git log --all --pretty=format:"%an %ad" -- pom.xml xxxx xxxx Mon Nov 23 03:09:17 2009 +0000 xxxx xxxx Mon Nov 23 02:42:24 2009 +0000

G:\ws_test_env\GIT_TESTBED_TMP\fest-swing-1.x>git log --all "--pretty=format:"%an %ad"" -- pom.xml fatal: bad revision '%ad'

G:\ws_test_env\GIT_TESTBED_TMP\fest-swing-1.x>git log --all "--pretty=format:"%an" "%ad"" -- pom.xml xxxx xxxx Mon Nov 23 03:09:17 2009 +0000 xxxx xxxx Mon Nov 23 02:42:24 2009 +0000

G:\ws_test_env\GIT_TESTBED_TMP\fest-swing-1.x>git log --all "--pretty=format:"%an" " %ad"" -- pom.xml fatal: bad revision '%ad'

G:\ws_test_env\GIT_TESTBED_TMP\fest-swing-1.x>git log --all "--pretty=format:"%an" "%ad"" -- pom.xml xxxx xxxx Mon Nov 23 03:09:17 2009 +0000 xxxx xxxx Mon Nov 23 02:42:24 2009 +0000

On Fri, May 2, 2014 at 1:50 PM, Dave Bradley <dbradley2@bell.net> wrote:

When you say "the #178 issue in github", you really mean "issue #178 for Git for Windows on GitHub", available at https://github.com/msysgit/git/issues/178 for those interested.

That issue tracker is for the Windows port of Git for Windows. It's intended to track breakages in Git for Windows compared to Git on, say Linux. It's not a general issue tracker for problems with Git. Still, it seems a lot of people think "I downloaded Git for Windows, and here's something that didn't work the way I expected it to, I'll file a bug". Those kinds of bug-reports usually gets closed quickly, as it's outside the scope of Git for Windows to decide how Git should behave - we try to make it behave consistently between Windows and Unixy-platforms.

This is indeed the right forum to address your issue. So thank you for moving the discussion here.

Erik Faye-Lund <kusmabite@gmail.com> writes:

Hmmmmmm, everything you said in the earlier paragraphs is correct, but I am having a feeling that this is either an issue specific to the Windows port, or more likely a user error, depending on who is giving the extra dq quoting. From the command line:

    $ git show --pretty='format:"%an %ad"'
    "Junio C Hamano Wed Apr 30 11:01:42 2014 -0700"

Because the 'format:' specifier requests to put dq around these two, we respond by putting dq around these two, just as we were asked to do. The way to ask %an followed by SP followed by %ad and nothing else is

    $ git show --pretty='format:%an %ad'
    Junio C Hamano Wed Apr 30 11:01:42 2014 -0700

Especially this part from the original tells me that this is a user error and there is nothing wrong in either the generic Git or in the Windows port.

    G:\w....x>git log --all "--pretty=format:"%an %ad"" -- pom.xml
    fatal: bad revision '%ad'

Separating the tokens on that command line, we would get:

    git
    log
    --all
    --pretty=format:%an
    %ad
    --
    pom.xml

So it told git to run the log subcommand with arguments that tells it to "include all tips of refs to the starting set", "show them using a custom format %an", "include %ad to the starting set", "everything that follows are not revs but pathspecs", and then finally "pom.xml is the pathspec to limit to paths the user is interested in". "%ad is not a rev" is perfectly valid.

You cannot take --pretty=format:"%ad %an" that you see in tutorials and random web pages too literally. The double quotes you see in that example is our way to tell that "--pretty=format:%ad %an" (what is inside these dq) is expected to be fed to Git as a single argument.

The examples you see typically follow the convention to show what you _would_ give to shell to achieve that, and shell's command line parser needs these dq to make sure that the SP between %an and %ad is not taken as an argument separator.

Your custom front-end may take a different approach to let you specify what individual arguments are on your command line, and you would have to follow its convention. The user needs to be careful about how shell quoting works on his/her command line, and that is all, I would think.

Visiting an earlier part of the original issue report:

    Getting a fatal failure when using the following
    --pretty=format:"%an %ad" via a programmed execution from within
    a programming language. (Java using the execution capabilities
    puts the ' --pretty=format:"%an %ad" ' as an argument).

I take that "Java using ..." to mean that the user wants to see his machinery eventually do an equivalent to:

	execl('git', 'git', 'log', '--pretty=format:%an %ad', ...);

but it somehow is getting

	execl('git', 'git', 'log', '--pretty=format:%an', '%ad', ...);

due to reason unknown to us that is not in the report.

Without knowing what the end-user input to the front-end that calls into that "Java" machinery is and what the argument separating convention that is employed by the front-end is, I cannot tell where the single argument is split into two. The problem may either be in that front-end program and not in the end-user input. Or the problem may be in Windows port letting the Windows library split command line at a funny point. In any case, it does not sound like it is a problem in Git. If the command fed to the equivalent to execl() above were not 'git' but any program, it will suffer from the same issue.

Hi Dave,

Dave Bradley wrote:

On Linux, this example gets passed to git as six arguments:

	log
	--all
	--pretty=format:%an
	%ad
	--
	pom.xml

I think the intent was instead to pass five arguments (the third being '--pretty=format:%an %ad'). That means you shouldn't unquote before the space, or in other words that the space should be part of a quoted argument.

On Windows, I believe the argument passing convention is more complicated. Programs can inspect the entire command line if they want to. But there's still an ambiguity in the command you passed: if I look at space-separated or double-quoted parts of the command line, it looks like

	git
	log
	--all
	"--pretty=format:"
	(no space)
	%an
	%ad
	(no space)
	""
	--
	pom.xml

What's the right way to parse this? How can git tell whether %an %ad were meant to be separate arguments or not? In absence of a stronger convention I suspect the simplest rule is to mimic what a Unix shell does, where they are separate arguments because the space is not quoted.

Cc-ing Windows folks in case they have more insight.

Thanks and hope that helps, Jonathan

(resending with the correct address for the Git for Windows developers. Sorry for the noise.) Hi Dave,

Dave Bradley wrote:

On Linux, this example gets passed to git as six arguments:

	log
	--all
	--pretty=format:%an
	%ad
	--
	pom.xml

I think the intent was instead to pass five arguments (the third being '--pretty=format:%an %ad'). That means you shouldn't unquote before the space, or in other words that the space should be part of a quoted argument.

On Windows, I believe the argument passing convention is more complicated. Programs can inspect the entire command line if they want to. But there's still an ambiguity in the command you passed: if I look at space-separated or double-quoted parts of the command line, it looks like

	git
	log
	--all
	"--pretty=format:"
	(no space)
	%an
	%ad
	(no space)
	""
	--
	pom.xml

What's the right way to parse this? How can git tell whether %an %ad were meant to be separate arguments or not? In absence of a stronger convention I suspect the simplest rule is to mimic what a Unix shell does, where they are separate arguments because the space is not quoted.

Cc-ing Windows folks in case they have more insight.

Thanks and hope that helps, Jonathan

On Fri, May 2, 2014 at 7:23 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

As does it on Windows.

Hi,

Interesting discussion. However, the example below of three-spaces between "%an" and "%ad" in the example below resulted in the formatting of the output with the three spaces, but no dq's.

This added to my confusion as by right dq within dq should be formatted. (Yea right, these days its needs to be escaped. But haven't tried that.)

In summary so far, it would appear that the --pretty......... needs to be contained in double-quotes as a whole. This was the solution I applied to my problem.

In the discussions I've seen more information requested as to the arguments provided to the execution class. I solved this issue as I made it work by experiment. I format the argument as a whole and don't have the space. IE. "pretty=format:"name:%an%nauthor:%ad%n"".

Regards

-----Original Message----- 
From: Erik Faye-Lund
Sent: Friday, May 02, 2014 2:23 PM
To: Jonathan Nieder
Cc: Dave Bradley ; GIT Mailing-list ; msysGit
Subject: Re: [msysGit] Re: #178 parsing of pretty=format:"%an %ad" causes 
fatal: bad revision '%ad'

On Fri, May 2, 2014 at 7:23 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

As does it on Windows. 

Dave Bradley <dbradley2@bell.net> writes:

I do not see any dq within dq here. Perhaps you need to count again to see which one pairs with which one.

What I see are these three strings concatenated together:

        --pretty=format: (which does not need any dq)
        %an"   "%ad     (the dq protects 3 SPs inside)
                        (an empty string inside the final dq pair)

So the single parameter that begins with --pretty given to "git log" is exactly the same as what is inside the single dq pair in the following:

	"--pretty=format:%an   %ad"

A more conventional way to spell it may however be one of:

	--pretty=format:"%an   %ad"
	--pretty="format:%an   %ad"