# [BUG?] trailer command with multiple keys 2 messages from 2016-06-06 to 2016-06-06. Participants: Michael J Gruber, Christian Couder. Thread: https://gitlist.dev/t/42537 ## Michael J Gruber, 2016-06-06 12:27 Subject: [BUG?] trailer command with multiple keys Message-ID: URL: https://gitlist.dev/e/b94e1666-2f89-619b-112c-023f72002d9d%40drmicha.warpmail.net ``` The command printf "body\n\ntest: foo\ntest: froz\n" | git -c trailer.test.key=tested -c trailer.test.command="echo by \$ARG" interpret-trailers gives: body tested: foo tested: froz tested: by froz I expected the command to be run on each "test" key, resulting in the output: body: tested: by foo tested: by froz (In a real life scenario, I would use ifexists replace.)[*] Maybe my expectation is wrong? The code breaks out of the loop after the first matching in_tok, apparently intentionally so. But I'm not sure - the key is replaced for both instances. Simply replacing that "return 1" by a "ret = 1" etc. runs into problems with the way the freeing of in_tok and arg_tok is arranged there :| Basically, I expected the trailer command to work "grep/sed-like" on all key value pairs that have matching keys, passing the value to the command, and using the (each) command's output as the new value for each of these pairs. Michael [*] My prime use case: fill in reported-by etc. with short author names, completed the same way we complete --author=jun using a trailer command (interpret-trailers in the commit-msg hook): $ git help author `git author' is aliased to `!f() { a=$(git log -1 --all -i --format="%aN <%aE>" --author "$1"); echo ${a:-$1}; }; f' $ cat .git/hooks/commit-msg #!/bin/sh git interpret-trailers --in-place "$1" $ git config --get-regexp trailer trailer.report.key Reported-by trailer.report.command git author '$ARG' trailer.report.ifexists replace trailer.report.ifmissing doNothing ``` ## Christian Couder, 2016-06-06 17:07 Subject: Re: [BUG?] trailer command with multiple keys Message-ID: URL: https://gitlist.dev/e/CAP8UFD3ZE3XooL02DNEvDO85uBK_%2BFpTiqb%2Bcx5hZ83tWassNg%40mail.gmail.com In-Reply-To: ``` On Mon, Jun 6, 2016 at 2:27 PM, Michael J Gruber wrote: > The command > > printf "body\n\ntest: foo\ntest: froz\n" | git -c > trailer.test.key=tested -c trailer.test.command="echo by \$ARG" > interpret-trailers > > gives: > > body > > tested: foo > tested: froz > tested: by froz > > I expected the command to be run on each "test" key, resulting in the > output: > > body: > > tested: by foo > tested: by froz > > (In a real life scenario, I would use ifexists replace.)[*] > > Maybe my expectation is wrong? I wouldn't say that it is wrong, but for now trailer configuration applies mostly to trailer passed as argument to `git interpret-trailers`. So you could perhaps get something close to what you want with: -------- $ printf "body\n\n" | git -c trailer.test.key=tested -c trailer.test.command="/home/christian/git/test/interpret-trailers/trailer-script.sh \$ARG" interpret-trailers --trim-empty --trailer='test: foo' --trailer='test: frotz' body tested: by foo tested: by frotz -------- and: -------- $ cat /home/christian/git/test/interpret-trailers/trailer-script.sh #!/bin/sh test -n "$1" && echo "by $1" : -------- > The code breaks out of the loop after the > first matching in_tok, apparently intentionally so. But I'm not sure - > the key is replaced for both instances. > > Simply replacing that "return 1" by a "ret = 1" etc. runs into problems > with the way the freeing of in_tok and arg_tok is arranged there :| > > Basically, I expected the trailer command to work "grep/sed-like" on all > key value pairs that have matching keys, passing the value to the > command, and using the (each) command's output as the new value for each > of these pairs. Yeah, it could have been designed like that. The problem is that something like: $ git config trailer.sign.key "Signed-off-by: " $ git config trailer.sign.ifmissing add $ git config trailer.sign.ifexists doNothing $ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"' and piping any commit message into "git interpret-trailers" should work too. In short it's not very natural to have both of the following by default: - a configured command should run once to get a chance to add a new trailer, even it doesn't exist in the input file - a configured command should run once per trailer in the input file (especially because as I said above for now configuration applies mostly to trailers on the command line). One solution could be to add support for a new trailer..commandMode config option that could take values like "onceAnyway", "oncePerMatchingTrailerInInputFile", "oncePerMatchingTrailerOnCommandLine" and it should be possible to use one or more of those modes, like for example: trailer.stuff.commandMode=onceAnyway,oncePerMatchingTrailerInInputFile > [*] My prime use case: fill in reported-by etc. with short author names, > completed the same way we complete --author=jun using a trailer command > (interpret-trailers in the commit-msg hook): > > $ git help author > `git author' is aliased to `!f() { a=$(git log -1 --all -i --format="%aN > <%aE>" --author "$1"); echo ${a:-$1}; }; f' > > $ cat .git/hooks/commit-msg > #!/bin/sh > git interpret-trailers --in-place "$1" > > $ git config --get-regexp trailer > trailer.report.key Reported-by > trailer.report.command git author '$ARG' > trailer.report.ifexists replace > trailer.report.ifmissing doNothing Yeah, it would be nice to be able to have things like that. ```