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Feature #8661

Add option to print backstrace in reverse order(stack frames first & error last)

Added by gary4gar (Gaurish Sharma) over 3 years ago. Updated about 1 month ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Target version:
-
[ruby-core:56096]

Description

Currently the way ruby prints the backtrace is that the error comes first & then the stack frames. like this

  Main Error Message
stack frame 1
stack frame 2
stack frame 3
.....

this is perfectly fine provided

  1. Backstraces are short, so fits in terminal.hence, no need to scroll.
  2. you read it from top to bottom.

But, I am a rails developer where

  1. Backstraces are always HUGE, therefore seldom don't fit in terminal. Means LOTS of scrolling to do everytime we get an error.
  2. in terminal we tend to read backstraces from bottom to top, especially when tailing(tail -f) the production logs.
  3. people, who practice Test-driven development literally spend most of their time scrolling to read backstraces to the point most end up buying a larger display.

Proposed Solution:
Please add a way so we can configure backstraces to be printed in reverse order. so if you are reading from bottom, say from terminal, you can get the main error message without need to scroll. like this

stack frame 3
stack frame 2
stack frame 1
 Main Error Message
..... 

this would save lot of time because when the error message is print at the bottom, no need to scroll for reading it. Not sure if this can be done today. I tried Overriding Exception#backtrace but it caused stack level too deep & illegal hardware instruction Error.

Attached are currently what backstrace currently looks like & how there be an option to make it look for comparison.

current.log View - here is currently backtraces are printed (5.13 KB) gary4gar (Gaurish Sharma), 07/21/2013 05:20 AM

proposed.log View - here is how I wish they could printed, so its easier read in terminal (4.9 KB) gary4gar (Gaurish Sharma), 07/21/2013 05:20 AM

Associated revisions

Revision 57685
Added by nobu (Nobuyoshi Nakada) about 1 month ago

eval_error.c: backstrace in reverse order

  • eval_error.c (rb_threadptr_error_print): print backtrace and error message in reverse order if STDERR is unchanged and a tty. [Feature #8661]

History

#1 [ruby-core:56109] Updated by jballanc (Joshua Ballanco) over 3 years ago

You can already accomplish something like this yourself:

begin
  raise "Hello!"
rescue Exception => e
  puts e.backtrace.reverse.join("\n")
  puts e.message
end

Simple!

#2 [ruby-core:56117] Updated by nobu (Nobuyoshi Nakada) over 3 years ago

(13/07/23 4:56), Joshua Ballanco wrote:

You can already accomplish something like this yourself:

begin
  raise "Hello!"
rescue Exception => e
  puts e.backtrace.reverse.join("\n")

You don't need to join.

  puts e.message
end

Simple!

#3 [ruby-core:78808] Updated by nofxx (Marcos Piccinini) 3 months ago

Already doing the rescue & reverse, but need to do it on every project...

Another use case is when using some monitor (e.g. guard) to run tests as you code:
When there's a fail one needs to switch to terminal and scroll up to see the lines that matter.

#4 [ruby-core:79669] Updated by nobu (Nobuyoshi Nakada) about 1 month ago

  • Description updated (diff)

#5 Updated by nobu (Nobuyoshi Nakada) about 1 month ago

  • Status changed from Open to Closed

Applied in changeset ruby-trunk:r57685.


eval_error.c: backstrace in reverse order

  • eval_error.c (rb_threadptr_error_print): print backtrace and error message in reverse order if STDERR is unchanged and a tty. [Feature #8661]

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