Re: [PATCH 2/2] tests: make forging GPG signed commits and tags more robust

> On rare occasions the given pattern occurs not only in the commit
> message but in the GPG signature as well, and after it's replaced in
> the signature the resulting signature becomes invalid, GPG will report
> CRC error and that it couldn't find any signature, which will then
> ultimately cause the test failure.

> Since in all three cases the pattern to be replaced during the forgery
> is the first word of the commit message's subject line, and since the
> GPG signature in the commit object is indented by a space, let's just
> anchor those patterns to the beginning of the line to prevent this
> issue.
> 
> The test script 't7030-verify-tag.sh' creates a forged signed tag
> object in a similar way by replacing the pattern "seventh", but the
> GPG signature in tag objects is not indented by a space, so the above
> solution is not applicable in this case.  However, in the tag object
> in question the pattern "seventh" occurs not only in the tag message
> but in the 'tag' header as well.  To create a forged tag object it's
> sufficient to replace only one of the two occurences, so modify the
> sed script to limit the pattern to the 'tag' header (i.e. a line
> beginning with "tag ", which, because of the space character, can
> never occur in the base64-encoded GPG signature).
> 
> Note that the forgery in 't7004-tag.sh' is not affected by this issue:
> while 't7004' does create a forged signed tag kind of the same way,
> it replaces "signed-tag" in the tag object, which, because of the '-'
> character, can never occur in the base64-encoded GPG signarute.