# [PATCH 3/4] update-hook: parse the tag header in preparation to use the tag type 4 messages from 2007-03-20 to 2007-03-20. Participants: Andy Parkins, Shawn O. Pearce. Thread: https://gitlist.dev/t/7329 ## Andy Parkins, 2007-03-20 10:58 Subject: [PATCH 3/4] update-hook: parse the tag header in preparation to use the tag type Message-ID: <200703201058.42753.andyparkins@gmail.com> URL: https://gitlist.dev/e/200703201058.42753.andyparkins%40gmail.com ``` The tag header is parsed with a while loop and read command. I'm not entirely sure how portable it is, as it had to use the following unusual heredoc format: while read field value do # .. done <<< "$(some command)" This was necessary because piping the output to a while doesn't work because the pipe is run in a separate process and hence setting variables inside it has no effect in the main script process. This "<<<" heredoc notation works around that problem, but I have no idea how widely supported it is. The alternative (should it be necessary) is to wastefully make multiple "git-cat-file | sed" calls - yuck. This patch also updates the user/time extraction from the "tagger" field to use the variable $tagger, rather than the "git-cat-file | sed" call used previously. Signed-off-by: Andy Parkins --- templates/hooks--update | 24 +++++++++++++++++++++--- 1 files changed, 21 insertions(+), 3 deletions(-) diff --git a/templates/hooks--update b/templates/hooks--update index 31e72ca..fd4c081 100644 --- a/templates/hooks--update +++ b/templates/hooks--update @@ -215,15 +215,33 @@ case "$refname_type" in echo " from $oldrev" fi + # Read the tag header + while read field value + do + case "$field" in + object) + tagobject="$value" + ;; + type) + tagtype="$value" + ;; + tag) + # Confirm that this tag has the right name? Nah + ;; + tagger) + tagger="$value" + ;; + esac + done <<< "$(git cat-file tag $newrev | head -q -n 4)" + # If this tag succeeds another, then show which tag it replaces prevtag=$(git describe --abbrev=0 $newrev^ 2>/dev/null) if [ -n "$prevtag" ]; then echo " replaces $prevtag" fi - # Read the tag details - eval $(git cat-file tag $newrev | \ - sed -n '4s/tagger \([^>]*>\)[^0-9]*\([0-9]*\).*/tagger="\1" ts="\2"/p') + # Extract user and time from tagger variable + eval $(sed -n 's/\([^>]*>\)[^0-9]*\([0-9]*\).*/tagger="\1" ts="\2"/p' <<< "$tagger") tagged=$(date --date="1970-01-01 00:00:00 +0000 $ts seconds" +"$DATEFORMAT") echo " tagged by $tagger" -- 1.5.0.3.402.g0c48 ``` ## Shawn O. Pearce, 2007-03-20 14:38 Subject: Re: [PATCH 3/4] update-hook: parse the tag header in preparation to use the tag type Message-ID: <20070320143844.GA1750@spearce.org> URL: https://gitlist.dev/e/20070320143844.GA1750%40spearce.org In-Reply-To: <200703201058.42753.andyparkins@gmail.com> ``` Andy Parkins wrote: > The tag header is parsed with a while loop and read command. I'm not > entirely sure how portable it is, as it had to use the following unusual > heredoc format: > > while read field value > do > # .. > done <<< "$(some command)" To bad you can't use for-each-ref. ;-) The problem of course is the update hook is running before a ref is created to point at the tag. If you used post-receive hook on the other hand... Oh, right, that has its own problems too! -- Shawn. ``` ## Andy Parkins, 2007-03-20 15:24 Subject: Re: [PATCH 3/4] update-hook: parse the tag header in preparation to use the tag type Message-ID: <200703201524.04282.andyparkins@gmail.com> URL: https://gitlist.dev/e/200703201524.04282.andyparkins%40gmail.com In-Reply-To: <20070320143844.GA1750@spearce.org> ``` On Tuesday 2007 March 20 14:38, Shawn O. Pearce wrote: > The problem of course is the update hook is running before a ref > is created to point at the tag. If you used post-receive hook > on the other hand... Oh, right, that has its own problems too! I've obviously not described the problem very well; as I don't understand how your comment relates to this patch. All I'm doing is pulling the individual fields out of $ git cat-file -p v1.5.0 object 437b1b20df4b356c9342dac8d38849f24ef44f27 type commit tag v1.5.0 tagger Junio C Hamano Wed Feb 14 00:00:00 2007 +0000 And putting them in their own variables. I'm not sure how for-each-ref or in fact, any ref-based tool would help me do this. At this point it's nothing to do with git, it's a standard shell script problem. git cat-file -p $newrev | while read field value do variable = "found" done echo $variable Doesn't work, because the right half of the pipe is run in its own process and so setting "variable" has no effect once the while loop is over. I found that "<<<" heredoc thing in the bash manual, which is almost like having a reverse pipe and allows the while loop to run in the main process. Andy -- Dr Andy Parkins, M Eng (hons), MIET andyparkins@gmail.com ``` ## Shawn O. Pearce, 2007-03-20 15:38 Subject: Re: [PATCH 3/4] update-hook: parse the tag header in preparation to use the tag type Message-ID: <20070320153815.GD1750@spearce.org> URL: https://gitlist.dev/e/20070320153815.GD1750%40spearce.org In-Reply-To: <200703201524.04282.andyparkins@gmail.com> ``` Andy Parkins wrote: > On Tuesday 2007 March 20 14:38, Shawn O. Pearce wrote: > > > The problem of course is the update hook is running before a ref > > is created to point at the tag. If you used post-receive hook > > on the other hand... Oh, right, that has its own problems too! > > I've obviously not described the problem very well; as I don't understand how > your comment relates to this patch. > eval `git for-each-ref --format='taggername=%(taggername) taggerdate=%(taggerdate)' thetag` Then you have $taggername and $taggerdate available. ;-) The problem is, there is no ref to for-each over. :-( -- Shawn. ```