threads / patch / 42951

patchrebase-interactive: trim leading whitespace from progress count

Subject: [PATCH va/i18n-even-more] rebase-interactive: trim leading whitespace from progress count

## tl;dr

4 messages between Jul 28, 2016 and Jul 28, 2016. Diffs are folded; open one to read it.

replies: 3people: 4as markdown or json

Johannes Sixt· Jul 28, 2016, 17:47 UTC · lore

Interactive rebase uses 'wc -l' to write the current patch number in a progress report. Some implementations of 'wc -l' produce spaces before the number, leading to ugly output such as

  Rebasing (     3/8)
Remove the spaces using a trivial arithmetic evaluation.

Before 9588c52 (i18n: rebase-interactive: mark strings for translation) this was not a problem because printf was used to generate the text. Since that commit, the count is interpolated directly from a shell variable into the text, where the spaces remain. The total number of patches does not have this problem even though it is interpolated from a shell variable in the same manner, because the variable is set by an arithmetic evaluation.

Later in the script, there is a virtually identical case where leading spaces are trimmed, but it uses a pattern substitution:

todocount=$(git stripspace --strip-comments <"$todo" | wc -l) todocount=${todocount##* }

I did not choose this idiom because it adds a line of code, and there is already an arithmetic evaluation in the vicinity of the line that is changed here.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
---
 git-rebase--interactive.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to git-rebase--interactive.sh +1 −1
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index ded4595..e2da524 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -121,7 +121,7 @@ mark_action_done () {
 	sed -e 1q < "$todo" >> "$done"
 	sed -e 1d < "$todo" >> "$todo".new
 	mv -f "$todo".new "$todo"
-	new_count=$(git stripspace --strip-comments <"$done" | wc -l)
+	new_count=$(( $(git stripspace --strip-comments <"$done" | wc -l) ))
 	echo $new_count >"$msgnum"
 	total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
 	echo $total >"$end"

-- 
2.9.0.443.ga8520ad
Eric Sunshine· Jul 28, 2016, 18:22 UTC · re: Johannes Sixt · lore

Re: [PATCH va/i18n-even-more] rebase-interactive: trim leading whitespace from progress count

On Thu, Jul 28, 2016 at 1:47 PM, Johannes Sixt <j6t@kdbg.org> wrote:
Show 25 quoted lines
> Interactive rebase uses 'wc -l' to write the current patch number
> in a progress report. Some implementations of 'wc -l' produce spaces
> before the number, leading to ugly output such as
>
>   Rebasing (     3/8)
>
> Remove the spaces using a trivial arithmetic evaluation.
>
> Before 9588c52 (i18n: rebase-interactive: mark strings for
> translation) this was not a problem because printf was used to
> generate the text. Since that commit, the count is interpolated
> directly from a shell variable into the text, where the spaces
> remain. The total number of patches does not have this problem
> even though it is interpolated from a shell variable in the same
> manner, because the variable is set by an arithmetic evaluation.
>
> Later in the script, there is a virtually identical case where
> leading spaces are trimmed, but it uses a pattern substitution:
>
> todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
> todocount=${todocount##* }
>
> I did not choose this idiom because it adds a line of code, and
> there is already an arithmetic evaluation in the vicinity of the
> line that is changed here.

On the other hand, to a newcomer (not familiar with this patch), ${foo##* } is an obvious and intentional stripping of whitespace, whereas taking advantage of a side-effect of arithmetic evaluation to achieve the same is quite subtle and likely to be interpreted as pointless, thus forces the reader to consult 'blame' to understand why the code is the way it is.

Show 12 quoted lines
> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
> ---
> diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
> @@ -121,7 +121,7 @@ mark_action_done () {
>         sed -e 1q < "$todo" >> "$done"
>         sed -e 1d < "$todo" >> "$todo".new
>         mv -f "$todo".new "$todo"
> -       new_count=$(git stripspace --strip-comments <"$done" | wc -l)
> +       new_count=$(( $(git stripspace --strip-comments <"$done" | wc -l) ))
>         echo $new_count >"$msgnum"
>         total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
>         echo $total >"$end"
Jakub Narębski· Jul 28, 2016, 18:45 UTC · re: Eric Sunshine · lore

Re: [PATCH va/i18n-even-more] rebase-interactive: trim leading whitespace from progress count

W dniu 2016-07-28 o 20:22, Eric Sunshine pisze:
Show 33 quoted lines
> On Thu, Jul 28, 2016 at 1:47 PM, Johannes Sixt <j6t@kdbg.org> wrote:
>> Interactive rebase uses 'wc -l' to write the current patch number
>> in a progress report. Some implementations of 'wc -l' produce spaces
>> before the number, leading to ugly output such as
>>
>>   Rebasing (     3/8)
>>
>> Remove the spaces using a trivial arithmetic evaluation.
>>
>> Before 9588c52 (i18n: rebase-interactive: mark strings for
>> translation) this was not a problem because printf was used to
>> generate the text. Since that commit, the count is interpolated
>> directly from a shell variable into the text, where the spaces
>> remain. The total number of patches does not have this problem
>> even though it is interpolated from a shell variable in the same
>> manner, because the variable is set by an arithmetic evaluation.
>>
>> Later in the script, there is a virtually identical case where
>> leading spaces are trimmed, but it uses a pattern substitution:
>>
>> todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
>> todocount=${todocount##* }
>>
>> I did not choose this idiom because it adds a line of code, and
>> there is already an arithmetic evaluation in the vicinity of the
>> line that is changed here.
> 
> On the other hand, to a newcomer (not familiar with this patch),
> ${foo##* } is an obvious and intentional stripping of whitespace,
> whereas taking advantage of a side-effect of arithmetic evaluation to
> achieve the same is quite subtle and likely to be interpreted as
> pointless, thus forces the reader to consult 'blame' to understand why
> the code is the way it is.

On the gripping hand, the number of currently processed commits (instructions) in an interactive rebase is a number, and arithmetic expansion can be understood as shell equivalent of casting to integer.

Show 12 quoted lines
>> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
>> ---
>> diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
>> @@ -121,7 +121,7 @@ mark_action_done () {
>>         sed -e 1q < "$todo" >> "$done"
>>         sed -e 1d < "$todo" >> "$todo".new
>>         mv -f "$todo".new "$todo"
>> -       new_count=$(git stripspace --strip-comments <"$done" | wc -l)
>> +       new_count=$(( $(git stripspace --strip-comments <"$done" | wc -l) ))
>>         echo $new_count >"$msgnum"
>>         total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
>>         echo $total >"$end"
Junio C Hamano· Jul 28, 2016, 20:30 UTC · re: Jakub Narębski · lore

Re: [PATCH va/i18n-even-more] rebase-interactive: trim leading whitespace from progress count

Jakub Narębski <jnareb@gmail.com> writes:
> On the gripping hand, the number of currently processed commits
> (instructions) in an interactive rebase is a number, and arithmetic
> expansion can be understood as shell equivalent of casting to integer.

I get that argument; it is a bit too cute a justification for my taste, but the resulting code is consistent with how $total loses the potential leading whitespace, so I'll queue it as-is.

Thanks.
Show 13 quoted lines
>
>>> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
>>> ---
>>> diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
>>> @@ -121,7 +121,7 @@ mark_action_done () {
>>>         sed -e 1q < "$todo" >> "$done"
>>>         sed -e 1d < "$todo" >> "$todo".new
>>>         mv -f "$todo".new "$todo"
>>> -       new_count=$(git stripspace --strip-comments <"$done" | wc -l)
>>> +       new_count=$(( $(git stripspace --strip-comments <"$done" | wc -l) ))
>>>         echo $new_count >"$msgnum"
>>>         total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
>>>         echo $total >"$end"

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