Cannot get Magit to show the commit signatures in the log

Question

In order to prove that I had a signature on a commit I needed to use a this command line command:

   $ git log --show-signature -1

I could not get Magit to display the signature I tried to use the Magit Key (l) and the -S switch.

But could not see the signature details.

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Addressing questions to the answer from the magit author

I ran out of space in my comment so I edited my question to reply.

So I validated that each commit was signed using git log --show-signature| cat in my shell in Emacs. Then I redid the command above and looked at individual rows to see the signature - but even when I hit RET as you say above, the signature still did not show up. I could also not see any evidence when all of the signatures were applied that any of them were signed.

How do I configure the expanded view of the signature so that the RET key will cause the details of the signature as the --show-signature flag requires? I most want to be able to drill in with RET and see exactly the text that is needed. I am concerned that I am missing details in magit that the shell shows properly.

Update 2020-06-29

magit-20200617.2306 is installed in the ~/.emacs.d/elpa/. directory

The signature now shows up in magit as a bright green color on the subject line of the commit message text

What remains is to add the details of the signature when a long form of the log message is used.

@tarsius I am fine with the signature details being omitted in the normal case when just one line is shown.

The bright green color is very useful to show that the commit is signed.

Answer 1

The --show-signature argument can be selected in the log popup but it is not actually passed to git log. Instead %G? is added to the value of the --format= argument.

That (%G?) causes some letter to be printed for each commit and the code that parses the log output detects that letter and uses it to determine what face should be used to display the commit message summary. The faces are named magit-signature-.... By default commits with "unproblematic" signatures are displayed the same way as regular text (i.e. like the default face), while other commits are displayed using some flashy color and therefore easily detected.

The reason the signatures are not shown in the log buffer is that Magit usually displays each commit on a single line. Displaying each commits signature on multiple lines would mess that up.

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To actually find out what is wrong about the signature you will have to visit the commit itself by pressing RET while point is on that commit in the log.

By default the revision buffer also does not show the signature. To show the signature you have to enable the --show-signature argument for the revision buffer also. To do so visit the revision buffer as usual. Then type D to change the diff arguments used in the current buffer. Then enable the respective argument using = g and finally save that as the default while also refreshing the current buffer using w.