I'm using C# and VB.NET.
I often (every days...) add comments to existing source files. When I check-in these files, I would like to have my merge tool to ignore any changes made to comments - I just want to be sure that I did not change the code.
I use WinMerge and Team Foundation Control Server (yes, no chance : Subversion was not an option when I accepted this job :o). Both of them can ignore white spaces but cannot ignore comments. Result : I have to carefully look at all the changes that I have made to each file before checking them in. And this is pretty cumbersome.
(Well, since most of my co-workers do not comment at all -- hey, they use pretty long namespace/class/methods/property/type/constant names that tell it all, guys ! -- it's a lot of work.)
Any suggestions ?
All the best,
Sylvain.
BeyondCompare has a filter for ignoring "unimportant" changes and comments belong to that category by default.
Compare++ has an option "Ignore comment changes" and "Ignore pure formatted changes" which should honor your request.
You said you used WinMerge - well it has the ability to filter out comments.
However it only works for comments that are on a separate line, so for example:
int i; // comment
will be detected as different from
int i;
It sounds like you're using commenting as a tool to understand the code as you work with it. That's an interesting idea, the equivalent of highlighting a book or taking notes. But you need to make sure you strip out all these transient comments before working with others.
Before comparing or promoting, run your source files through a filter program that strips the comment. This could be a one-liner perl script.
To make it easier, use a distinctive pattern for your non-permanent comments, to make them easier to filter out (and to distinguish between these transient comments, and comments you really want to leave in the source). E.g. if you were writing in C++, always comment using
//Sylvain: this is my comment here.
or some other pattern that is even easier to grep for.
If the content of the comments are not something you care about, and do not matter, why not delete them?
If well documented code that is readable and understandable is part of what you create, why not review changes to that meta-data?
Adding comment to your code is smell that your code is hard to read, code should be self describing, like someone has said that , good code is like good joke, it does not need to be explained. It is better to change your variable name, put section of your code into a subroutine. Re factoring is better than commenting. Even you find a tool to solve you commenting problem, it does not solve the real problem that is make you code easy to understand.
Related
For text, not source code, files like LaTeX, markdown, restructuredText, usually single line breaks does not matter for the semantics and they are frequently refilled within 80 columns. When things are changed, the line break might change by quite a lot. So the common line-by-line diff and patch tools do not actually work for them very well. So I am wondering if there already exist good tools for diffing, patching and even merging this kind of changes? wdiff and git diff --color-words does exactly the kind of thing, but they seem to lack the patching and merging capability. Ideally, if we have got a line
He do not owe us nothing.
and one author changed it into
He do not owe us anything.
and another author changed it into
He does not owe us nothing.
then a merge could give
He does not owe us anything.
without conflict. That is the ideal result. Thanks in advance.
Besides meld, you can also use Beyond Compare or WinMerge
I'd like to check hardcoded values in (a lot of) Smartforms and SAPScript forms.
I have found a way to read the source code of both of these, but it seems that i will have to go through a lot of parsing before I get anything reliable.
I've come across function module GET_LITERAL but that doesn't seem to help me much since i have to specify the offset of the value, if i got right what the function is doing in the first place.
I also found RS_LITERAL_LIST but that also doesn't do what i expect.
I also tried searching for reports and methods, but haven't found anything that seemed to help.
A backup plan would be to get some good parsing tool, so do you know of anything like that.
Anyway, any hints would be helpful and appreciated.
[EDIT]
Forgot to mention, the version of my system is 4.6C
If you have a fairly recent version of ABAP, you can use a regex.
Follow the pattern of this example, but use your source as the text and create your own regex. Have it look for any single quotes on the end of a word separated by spaces or any integers with spaces on either side. That's just a start, you might need to work on a better pattern.
String functions count, find, and match
In some code coverage tools you can "hide" certain lines of code from the coverage tool, so that those lines do not count towards the coverage totals. For example, some code might be run only in circumstances that are hard or impossible to test (such as certain hardware failures). Thus, you might get 100% coverage reported even though some code was not exercised.
Setting aside for the moment whether this is wise, is this sort of thing possible with Perl's Devel::Cover?
(Devel::Cover can ignore entire files, but I am interested in ignoring just a few lines in a single file.)
A lot of uncoverable code features have been implemented but they are not documented because I wasn't sure of the interface. However, it's been a few years since anything changed in that area.
Probably the easiest way to see how to use the features is to look at tests/uncoverable in the distribution (see https://github.com/pjcj/Devel--Cover/blob/master/test/uncoverable). If you can't or don't want to change your code you can use the .uncoverable file (see https://github.com/pjcj/Devel--Cover/blob/master/tests/.uncoverable) and the cover options as mentioned by toolic.
If you do this, be sure to use the basic_html report which will mark a construct as in error if you tag it as uncoverable but it gets executed anyway.
I really should get around to tidying everything up and documenting it.
According to the TODO file on CPAN, this capability is not currently supported, but the developers see it as a valuable addition:
Enhancements:
Marking of unreachable code - commandline tool and gui.
The cover script mentions promising options: -add_uncoverable_point and -delete_uncoverable_point.
I'm working on a new weave-based data structure for storing version control history. This will undoubtedly cause some religious wars about whether it's The Right Way Of Doing Things when it comes out, but that isn't my question right now.
My question has to do with what output blame should give. When a line of code has been added, removed, and merged into itself a number of times, it isn't always clear what revision should get blame for it. Notably this means that when a section of code is deleted, all records of it having been there is gone, and there is no blame for the removal. Everyone I've gone over this issue with has said that trying to do better simply isn't worth it. Sometimes people put in the hack that the line after the section which got deleted has its blame changed from whatever it actually was to the revision when the section got deleted. Presumably if the section is at the end then the last line get its blame changed, and if the file winds up empty then the blame really does disappear into the aether, because there's literally nowhere left to put blame information. For various technical reasons I won't be using this hack, but assume that continuing but with this completely undocumented but de facto standard practice will be uncontroversial (but feel free to flame me and get it out of your system).
Moving on to my actual question. Usually in blame for each line you look at the complete history of where it was added and removed in the history and using three-way merge (or, in the case of criss-cross merges, random bullshit) and based on the relationships between those you determine whether the line should have been there based on its history, and if it shouldn't but is then you mark it as new with the current revision. In the case where a line occurs in multiple ancestors with different blames then it picks which one to inherit arbitrarily. Again, I assume that continuing with this completely undocumented but de facto standard practice will be uncontroversial.
Where my new system diverges is that rather than doing a complicated calculation of whether a given line should be in the current revision based on a complex calculation of the whole history, it simply looks at the immediate ancestors, and if the line is in any of them it picks an arbitrary one to inherit the blame from. I'm making this change for largely technical reasons (and it's entirely possible that other blame implementations do the same thing, for similar technical reasons and a lack of caring) but after thinking about it a bit part of me actually prefers the new behavior as being more intuitive and predictable than the old one. What does everybody think?
I actually wrote a one of the blame implementations out there (Subversion's current one I believe, unless someone replaced it in the past year or two). I helped with some others as well.
At least most implementations of blame don't do what you describe:
Usually in blame for each line you look at the complete history of where it was added and removed in the history and using three way merge (or, in the case of criss-cross merges, random bullshit) and based on the relationships between those you determine whether the line should have been there based on its history, and if it shouldn't but is then you mark it as new with the current revision. In the case where a line occurs in multiple ancestors with different blames then it picks which one to inherit arbitrarily. Again, I assume that continuing with this completely undocumented but de facto standard practice will be uncontroversial.
Actually, most blames are significantly less complex than this and don't bother trying to use the relationships at all, but they just walk parents in some arbitrary order, using simple delta structures (usually the same internal structure whatever diff algorithm they have uses before it turns it into textual output) to see if the chunk changed, and if so, blame it, and mark that line as done.
For example, Mercurial just does an iterative depth first search until all lines are blamed. It doesn't try to take into account whether the relationships make it unlikely it blamed the right one.
Git does do something a bit more complicated, but still, not quite like you describe.
Subversion does what Mercurial does, but the history graph is very simple, so it's even easier.
In turn, what you are suggesting is, in fact, what all of them really do:
Pick an arbitrary ancestor and follow that path down the rabbit hole until it's done, and if it doesn't cause you to have blamed all the lines, arbitrarily pick the next ancestor, continue until all blame is assigned.
On a personal level, I prefer your simplified option.
Reason: Blame isn't used very much anyway.
So I don't see a point in wasting a lot of time doing a comprehensive implementation of it.
It's true. Blame has largely turned out to be one of those "pot of gold at the end of the rainbow" features. It looked really cool from those of us standing on the ground, dreaming about a day when we could just click on a file and see who wrote which lines of code. But now that it's widely implemented, most of us have come to realize that it actually isn't very helpful. Check the activity on the blame tag here on Stack Overflow. It is underwhemingly desolate.
I have run across dozens of "blame-worthy" scenarios in recent months alone, and in most cases I have attempted to use blame first, and found it either cumbersome or utterly unhelpful. Instead, I found the information I needed by doing a simple filtered changelog on the file in question. In some cases, I could have found the information using Blame as well, had I been persistent, but it would have taken much longer.
The main problem is code formatting changes. The first-tier blame for almost everything was listed as... me! Why? Because I'm the one responsible for fixing newlines and tabs, re-sorting function order, splitting functions into separate utility modules, fixing comment typos, and improving or simplifying code flow. And if it wasn't me, someone else had done a whitespace or block-move somewhere along-the-way as well. In order to get a meaningful blame on anything dating back to a time before I can already remember without the help of blame, I had to roll back revisions and re-blame. And re-blame again. And again.
So in order for a blame to actually be a useful time saver for more than the most lucky of situations, the blame has to be able to heuristicly make its way past newline, whitespace, and ideally block copy/move changes. That sounds like a very tall order, especially when scouring the changelog for a single file, most of the time, it won't yield many diffs anyway and you can just sift through by hand fairly quickly. (The notable exception being, perhaps, badly engineered source trees where 90% of the code is stuffed in one or two ginormous files... but who these days in a collaborative coding environment does much of that anymore?).
Conclusion: Give it a bare-bones implementation of blame, because some people like to see "it can blame!" on the features list. And then move on to things that matter. Enjoy!
The line-merge algorithm is stupider than the developer. If they disagree, that just indicates that the merger is wrong rather than indicating a decision point. So, the simplified logic should actually be more correct.
What source control products have a "diff" facility that ignores white space, braces, etc., in calculating the difference between checked-in versions? I seem to remember that Clearcase's diff did this but Visual SourceSafe (or at least the version I used) did not.
The reason I ask is probably pretty typical. Four perfectly reasonable developers on a team have four entirely different ways of formatting their code. Upon checking out the code last changed by someone else, each will immediately run some kind of program or editor macro to format things the way they like. They make actual code changes. They check-in their changes. They go on vacation. Two days later that program, which had been running fine for two years, blows up. The developer assigned to the bug does a diff between versions and finds 204 differences, only 3 of which are of any significance, because the diff algorithm is lame.
Yes, you can have coding standards. Most everyone finds them dreadful. A solution where everyone can have their cake and eat it too seems far more preferable.
=========
EDIT: Thanks to everyone for some great suggestions.
What I take away from this is:
(1) A source control system with plug-in type diffs is preferable.
(2) Find a diff with suitable options.
(3) Use a good source formatting program and settle on a check-in standard.
Sounds like a plan. Thanks again.
Git does have these options:
--ignore-space-at-eol
Ignore changes in whitespace at EOL.
-b, --ignore-space-change
Ignore changes in amount of whitespace. This ignores whitespace at line end, and considers all other sequences of one or more
whitespace characters to be equivalent.
-w, --ignore-all-space
Ignore whitespace when comparing lines. This ignores differences even if one line has whitespace where the other line has
none.
I am not sure if brace changes can be ignored using Git's diff.
If it is C/C++ code, you can define Astyle rules and then convert the source code's brace style to the one that you want, using Astyle. A git diff will then produce sane output.
Choose one (dreadful) coding standard, write it down in some official coding standards document, and get on with your life, messing with whitespace is not productive work.
And remember you are a professional developer, it's your job to get the project done, changing anything in the code because of a personal style preference hurts the project - it wont only make diff-ing more difficult, it can also introduce hard to find problems if your source formatter or compiler has bugs (and your fancy diff tool won't save you when two co-worker start fighting over casing).
And if someone just doesn't agree to work with the selected style just remind him (or her) that he is programming as a profession not as an hobby, see http://www.ericsink.com/entries/No_Great_Hackers.html
Maybe you should choose one format and run some indentation tool before checking in so that each person can check out, reformat to his/her own preferences, do the changes, reformat back to the official standard and then check in?
A couple of extra steps but they already use indentation tools when working. Maybe it can be a triggered check-in script?
Edit: this would perhaps also solve the brace problem.
(I haven't tried this solution myself, hence the "perhapes" and "maybes", but I have been in projects with the same problems, and it is a pain to try to go through diffs with hundreds of irrelevant changes that are not limited to whitespace, but includes the formatting itself.)
As explained in Is it possible for git-merge to ignore line-ending differences?, it is more a matter to associate the right diff tool to your favorite VCS, rather than to rely on the right VCS option (even if Git does have some options regarding whitespace, like the one mentioned in Alan's answer, it will always be not as complete as one would like).
DiffMerge is the more complete on those "ignore" options, as it can not only ignore spaces but also other "variations" based on the programming language used in a given file.
Subversion apparently supports this, either natively in the latest versions, or by using an alternate diff like Gnu Diff.
Beyond Compare does this (and much much more) and you can integrate it either in Subversion or Sourcesafe as an external diff tool.