Re: vc-modify-change-comment for "modern" backend fix

["Alfred M. Szmidt" <ams@gnu.org>]

   >     The backend command could be called 'extract-comment'. Which is somewhat
   >     different from "log entry" because the latter seems to include the
   >     headers, in VC parlance.
   > 
   > 
   >     And you haven't explained thus far your plan for implementing
   >     'modify-change-comment' for e.g. Git.
   > 
   > I have no plans on implementing such functionality for git.

   Okay, but how will this work in fossil? Similar to editing a single 
   commit during a rebase?

Fossil has no concept of rebase.  Amending makes a new commit, and the
last commit message is shown when viewing the timeline/log.

~/tt $ fossil timeline -R foo.fossil
=== 2022-05-17 ===
09:42:27 [3b410767c6] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:50:06 [30aa7e8b06] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:33:59 [1c13590b96] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:30:34 [73bf888ab9] zork zork zborkrkrk (user: ams tags: trunk)
07:30:02 [40289e9363] initial empty check-in (user: ams tags: trunk)
+++ no more data (5) +++
~/tt $ fossil amend -m "this is a new message" 40289e9363 -R foo.fossil 
hash:         40289e9363e0e3e1fe5e2df9c9827fe65e51f547 2022-05-17 07:30:02 UTC
tags:         trunk
comment:      this is a new message (user: ams)
~/tt $ fossil timeline -R foo.fossil
=== 2022-05-19 ===
09:56:34 [5a950dc2f6] Edit [40289e9363e0e3e1|40289e9363]: Edit check-in comment. (user: ams)
=== 2022-05-17 ===
09:42:27 [3b410767c6] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:50:06 [30aa7e8b06] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:33:59 [1c13590b96] Edit [73bf888ab97bd2c3|73bf888ab9]: Edit check-in comment. (user: ams)
07:30:34 [73bf888ab9] zork zork zborkrkrk (user: ams tags: trunk)
07:30:02 [40289e9363] this is a new message (user: ams tags: trunk)