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[PATCH] gitk: to run in a bare repository (was: gitk can't be run from non-worktree folders)

From
Junio C Hamano <gitster@pobox.com>
Date
Jan 23, 2020, 19:20 UTC
Message-ID
<xmqqk15i3rp7.fsf_-_@gitster-ct.c.googlers.com>
In-Reply-To
<xmqqpnfa3sj1.fsf@gitster-ct.c.googlers.com>
[This message is designed to be readable by "git am -c".]
Junio C Hamano <gitster@pobox.com> writes:
Show 33 quoted lines
> Eric Sunshine <sunshine@sunshineco.com> writes:
>
>> It's a new regression introduced by 2d92ab32fd (rev-parse: make
>> --show-toplevel without a worktree an error, 2019-11-19), as far as I
>> can tell. I have many times used gitk on bare repositories as an
>> interactive replacement for git-log, so this is a unfortunate bit of
>> fallout from that change. That's not to say that 2d92ab32fd should be
>> reverted, though... perhaps gitk itself needs a bit of a fix.
>
> Curious.
>
> There is a "proc gitworktree" that does use --show-toplevel but it
> is fairly conservative and assumes these calls can fail.
>
>     ...
>     if {[catch {set _gitworktree [exec git rev-parse --show-toplevel]}]} {
>         if {[catch { set _gitworktree $env(GIT_WORK_TREE) }]} {
> 	    catch {set _gitworktree [exec git config --get core.worktree]}
> 	    if {$_gitworktree eq ""} {
> 		set _gitworktree [file normalize ./[exec git rev-parse --show-cdup]]
> 	    }
>
> However, there is this call
>
>     set worktree [exec git rev-parse --show-toplevel]
>
> at the top-level of the code.  I wonder if the obvious and minimum
> fix would be sufficient, i.e.
>
>     -set worktree [exec git rev-parse --show-toplevel]
>     +set worktree [gitworktree]
>
> around l.12546

I've read 784b7e2f ("gitk: Fix "External diff" with separate work tree", 2011-04-04) again and am reasonably convinced that the above single liner would be "sufficient". The external_diff_get_one_file proc is written, with or without the "fix external diff" patch, to work ONLY in a non-bare repository (it used to find and use the parent directory of ".git" as the top-level of the working tree before 784b7e2f, which changed it to use $worktree global obtained by calling "rev-parse --show-toplevel") and does not work in a bare repository anyway, if I am reading the code correctly.

-- >8 --
Subject: [PATCH] gitk: be prepared to be run in a bare repository

784b7e2f ("gitk: Fix "External diff" with separate work tree", 2011-04-04) added an unconditional call to "git rev-parse --show-toplevel" to set up a global variable quite early in the course of the program, so that the location of the working tree can later be known if/when the user chooses to run the external diff via the external_diff_get_one_file proc. Before that change, the external diff code used to assume that the parent directory of ".git" directory is the top-level of the working tree.

Recent versions of git however notices that "rev-parse --show-toplevel" executed in a bare repository is an error, which makes gitk stop, even before the user could attempt to run external diff.

Use the gitworktree helper introduced in 65bb0bda ("gitk: Fix the display of files when filtered by path", 2011-12-13), which is prepared to see failures from "rev-parse --show-toplevel" and other means it tries to find the top-level of the working tree instead to work around this issue. The resulting value in $worktree global, when run in a bare repository, is bogus, but the code is not prepared to run external diff correctly without a working tree anyway ;-)

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 gitk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gitk b/gitk
index abe4805ade..1483bf5ed5 100755
--- a/gitk
+++ b/gitk
@@ -12599,7 +12599,7 @@ set cdup {}
 if {[expr {[exec git rev-parse --is-inside-work-tree] == "true"}]} {
     set cdup [exec git rev-parse --show-cdup]
 }
-set worktree [exec git rev-parse --show-toplevel]
+set worktree [gitworktree]
 setcoords
 makewindow
 catch {
Previous: Junio C HamanoNext: Eric Sunshine
Message 7 of 15 in “[REGRESSION] gitk can't be run from non-worktree folders”
  1. chJan 23, 2020
  2. SZEDER GáborJan 23, 2020
  3. Eric SunshineJan 23, 2020
  4. SZEDER GáborJan 23, 2020
  5. SZEDER GáborJan 23, 2020
  6. Junio C HamanoJan 23, 2020
  7. gitk: to run in a bare repository (was: gitk can't be run from non-worktree folders)Junio C Hamano, Jan 23, 2020
  8. Eric SunshineJan 23, 2020
  9. Jeff KingJan 23, 2020
  10. chMar 30, 2020
  11. Eric SunshineOct 11, 2020
  12. chOct 13, 2020
  13. Pratyush YadavOct 13, 2020
  14. chApr 2, 2020
  15. Junio C HamanoApr 2, 2020

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