Improve appearance of error messages

[ajeetdsouza]

Hey, thanks for this project! I'm using it quite a bit in zoxide to pass generated code through linters / formatters, and it's made my life a lot easier.

However, I do feel that errors could be formatted in a better way. I often have large amounts of text being compared in stdin / stdout. For example, here is some code that passes fish shell code through fishindent to check for proper formatting:

Command::new("fish")
  .env("HOME", tempdir)
  .args(&["--command", "fish_indent", "--private"])
  .write_stdin(source.to_string())
  .assert()
  .success()
  .stdout(source)
  .stderr("");

(expand me) This is what the output looks like.

running 1 test
test shell::tests::fish_fishindent::cmd_1::hook_1::echo_1::resolve_symlinks_1 ... FAILED

failures:

---- shell::tests::fish_fishindent::cmd_1::hook_1::echo_1::resolve_symlinks_1 stdout ----
-------------- TEST START --------------
thread 'shell::tests::fish_fishindent::cmd_1::hook_1::echo_1::resolve_symlinks_1' panicked at 'Unexpected stdout, failed var - original <= 0
├── original: # =============================================================================
#
# Utility functions for zoxide.
#

# pwd based on the value of _ZO_RESOLVE_SYMLINKS.
function __zoxide_pwd
    builtin pwd -L
end

# A copy of fish's internal cd function. This makes it possible to use
# `alias cd=z` without causing an infinite loop.
if ! builtin functions -q __zoxide_cd_internal
    if builtin functions -q cd
        builtin functions -c cd __zoxide_cd_internal
    else
        alias __zoxide_cd_internal="builtin cd"
    end
end

# cd + custom logic based on the value of _ZO_ECHO.
function __zoxide_cd
    __zoxide_cd_internal $argv
    and builtin commandline -f repaint
end

# =============================================================================
#
# Hook configuration for zoxide.
#

# Initialize hook to add new entries to the database.
if test "$__zoxide_hooked" != 1
    set __zoxide_hooked 1
    function __zoxide_hook
        test -z "$fish_private_mode"
        and command zoxide add -- (__zoxide_pwd)
    end
end

# =============================================================================
#
# When using zoxide with --no-aliases, alias these internal functions as
# desired.
#

# Jump to a directory using only keywords.
function __zoxide_z
    set argc (count $argv)
    if test $argc -eq 0
        __zoxide_cd $HOME
    else if test "$argv" = -
        __zoxide_cd -
    else if begin
            test $argc -eq 1; and test -d $argv[1]
        end
        __zoxide_cd $argv[1]
    else
        set -l __zoxide_result (command zoxide query --exclude (__zoxide_pwd) -- $argv)
        and __zoxide_cd $__zoxide_result
    end
end

# Jump to a directory using interactive search.
function __zoxide_zi
    set -l __zoxide_result (command zoxide query -i -- $argv)
    and __zoxide_cd $__zoxide_result
end

# =============================================================================
#
# Convenient aliases for zoxide. Disable these using --no-aliases.
#

# -- not configured --

# =============================================================================
#
# To initialize zoxide, add this to your configuration (usually
# ~/.config/fish/config.fish):
#
# zoxide init fish | source
├── actual distance: 1
├── diff: # =============================================================================
#
# Utility functions for zoxide.
#

# pwd based on the value of _ZO_RESOLVE_SYMLINKS.
function __zoxide_pwd
    builtin pwd -L
end

# A copy of fish's internal cd function. This makes it possible to use
# `alias cd=z` without causing an infinite loop.
if ! builtin functions -q __zoxide_cd_internal
    if builtin functions -q cd
        builtin functions -c cd __zoxide_cd_internal
    else
        alias __zoxide_cd_internal="builtin cd"
    end
end

# cd + custom logic based on the value of _ZO_ECHO.
function __zoxide_cd
    __zoxide_cd_internal $argv
    and builtin commandline -f repaint
end

# =============================================================================
#
# Hook configuration for zoxide.
#

# Initialize hook to add new entries to the database.
if test "$__zoxide_hooked" != 1
    set __zoxide_hooked 1
    function __zoxide_hook
        test -z "$fish_private_mode"
        and command zoxide add -- (__zoxide_pwd)
    end
end

# =============================================================================
#
# When using zoxide with --no-aliases, alias these internal functions as
# desired.
#

# Jump to a directory using only keywords.
function __zoxide_z
    set argc (count $argv)
    if test $argc -eq 0
        __zoxide_cd $HOME
    else if test "$argv" = -
        __zoxide_cd -
    else if begin
            test $argc -eq 1; and test -d $argv[1]
        end
        __zoxide_cd $argv[1]
    else
        set -l __zoxide_result (command zoxide query --exclude (__zoxide_pwd) -- $argv)
        and __zoxide_cd $__zoxide_result
    end
end

# Jump to a directory using interactive search.
function __zoxide_zi
    set -l __zoxide_result (command zoxide query -i -- $argv)
    and __zoxide_cd $__zoxide_result
end

# =============================================================================
#
# Convenient aliases for zoxide. Disable these using --no-aliases.
#

# -- not configured --

# =============================================================================
#
# To initialize zoxide, add this to your configuration (usually
# ~/.config/fish/config.fish):
#
# zoxide init fish | source


└── var as str: # =============================================================================
#
# Utility functions for zoxide.
#

# pwd based on the value of _ZO_RESOLVE_SYMLINKS.
function __zoxide_pwd
    builtin pwd -L
end

# A copy of fish's internal cd function. This makes it possible to use
# `alias cd=z` without causing an infinite loop.
if ! builtin functions -q __zoxide_cd_internal
    if builtin functions -q cd
        builtin functions -c cd __zoxide_cd_internal
    else
        alias __zoxide_cd_internal="builtin cd"
    end
end

# cd + custom logic based on the value of _ZO_ECHO.
function __zoxide_cd
    __zoxide_cd_internal $argv
    and builtin commandline -f repaint
end

# =============================================================================
#
# Hook configuration for zoxide.
#

# Initialize hook to add new entries to the database.
if test "$__zoxide_hooked" != 1
    set __zoxide_hooked 1
    function __zoxide_hook
        test -z "$fish_private_mode"
        and command zoxide add -- (__zoxide_pwd)
    end
end

# =============================================================================
#
# When using zoxide with --no-aliases, alias these internal functions as
# desired.
#

# Jump to a directory using only keywords.
function __zoxide_z
    set argc (count $argv)
    if test $argc -eq 0
        __zoxide_cd $HOME
    else if test "$argv" = -
        __zoxide_cd -
    else if begin
            test $argc -eq 1; and test -d $argv[1]
        end
        __zoxide_cd $argv[1]
    else
        set -l __zoxide_result (command zoxide query --exclude (__zoxide_pwd) -- $argv)
        and __zoxide_cd $__zoxide_result
    end
end

# Jump to a directory using interactive search.
function __zoxide_zi
    set -l __zoxide_result (command zoxide query -i -- $argv)
    and __zoxide_cd $__zoxide_result
end

# =============================================================================
#
# Convenient aliases for zoxide. Disable these using --no-aliases.
#

# -- not configured --

# =============================================================================
#
# To initialize zoxide, add this to your configuration (usually
# ~/.config/fish/config.fish):
#
# zoxide init fish | source


command=`"fish" "--command" "fish_indent" "--private"`
stdin=`"# =============================================================================\n#\n# Utility functions for zoxide.\n#\n\n# pwd based on the value of _ZO_RESOLVE_SYMLINKS.\nfunction __zoxide_pwd\n    builtin pwd -L\nend\n\n# A copy of fish\'s internal cd function. This makes it possible to use\n# `alias cd=z` without causing an infinite loop.\nif ! builtin functions -q __zoxide_cd_internal\n    if builtin functions -q cd\n        builtin functions -c cd __zoxide_cd_internal\n    else\n        alias __zoxide_cd_internal=\"builtin cd\"\n    end\nend\n\n# cd + custom logic based on the value of _ZO_ECHO.\nfunction __zoxide_cd\n    __zoxide_cd_internal $argv\n    and builtin commandline -f repaint\nend\n\n# =============================================================================\n#\n# Hook configuration for zoxide.\n#\n\n# Initialize hook to add new entries to the database.\nif test \"$__zoxide_hooked\" != 1\n    set __zoxide_hooked 1\n    function __zoxide_hook\n        test -z \"$fish_private_mode\"\n        and command zoxide add -- (__zoxide_pwd)\n    end\nend\n\n# =============================================================================\n#\n# When using zoxide with --no-aliases, alias these internal functions as\n# desired.\n#\n\n# Jump to a directory using only keywords.\nfunction __zoxide_z\n    set argc (count $argv)\n    if test $argc -eq 0\n        __zoxide_cd $HOME\n    else if test \"$argv\" = -\n        __zoxide_cd -\n    else if begin\n            test $argc -eq 1; and test -d $argv[1]\n        end\n        __zoxide_cd $argv[1]\n    else\n        set -l __zoxide_result (command zoxide query --exclude (__zoxide_pwd) -- $argv)\n        and __zoxide_cd $__zoxide_result\n    end\nend\n\n# Jump to a directory using interactive search.\nfunction __zoxide_zi\n    set -l __zoxide_result (command zoxide query -i -- $argv)\n    and __zoxide_cd $__zoxide_result\nend\n\n# =============================================================================\n#\n# Convenient aliases for zoxide. Disable these using --no-aliases.\n#\n\n# -- not configured --\n\n# =============================================================================\n#\n# To initialize zoxide, add this to your configuration (usually\n# ~/.config/fish/config.fish):\n#\n# zoxide init fish | source"`
code=0
stdout=```"# =============================================================================\n#\n# Utility functions for zoxide.\n#\n\n# pwd based on the value of _ZO_RESOLVE_SYMLINKS.\nfunction __zoxide_pwd\n    builtin pwd -L\nend\n\n# A copy of fish\'s internal cd function. This makes it possible to use\n# `alias cd=z` without causing an infinite loop.\nif ! builtin functions -q __zoxide_cd_internal\n    if builtin functions -q cd\n        builtin functions -c cd __zoxide_cd_internal\n    else\n        alias __zoxide_cd_internal=\"builtin cd\"\n    end\nend\n\n# cd + custom logic based on the value of _ZO_ECHO.\nfunction __zoxide_cd\n    __zoxide_cd_internal $argv\n    and builtin commandline -f repaint\nend\n\n# =============================================================================\n#\n# Hook configuration for zoxide.\n#\n\n# Initialize hook to add new entries to the database.\nif test \"$__zoxide_hooked\" != 1\n    set __zoxide_hooked 1\n    function __zoxide_hook\n        test -z \"$fish_private_mode\"\n        and command zoxide add -- (__zoxide_pwd)\n    end\nend\n\n# =============================================================================\n#\n# When using zoxide with --no-aliases, alias these internal functions as\n# desired.\n#\n\n# Jump to a directory using only keywords.\nfunction __zoxide_z\n    set argc (count $argv)\n    if test $argc -eq 0\n        __zoxide_cd $HOME\n    else if test \"$argv\" = -\n        __zoxide_cd -\n    else if begin\n            test $argc -eq 1; and test -d $argv[1]\n        end\n        __zoxide_cd $argv[1]\n    else\n        set -l __zoxide_result (command zoxide query --exclude (__zoxide_pwd) -- $argv)\n        and __zoxide_cd $__zoxide_result\n    end\nend\n\n# Jump to a directory using interactive search.\nfunction __zoxide_zi\n    set -l __zoxide_result (command zoxide query -i -- $argv)\n    and __zoxide_cd $__zoxide_result\nend\n\n# =============================================================================\n#\n# Convenient aliases for zoxide. Disable these using --no-aliases.\n#\n\n# -- not configured --\n\n# =============================================================================\n#\n# To initialize zoxide, add this to your configuration (usually\n# ~/.config/fish/config.fish):\n#\n# zoxide init fish | source\n"```
stderr=```""```
', /home/ajeetdsouza/.cargo/registry/src/github.colasdn.workers.dev-1ecc6299db9ec823/assert_cmd-1.0.3/src/assert.rs:341:17
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    shell::tests::fish_fishindent::cmd_1::hook_1::echo_1::resolve_symlinks_1

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 448 filtered out; finished in 0.05s

error: test failed, to rerun pass '--bin zoxide'

On closer inspection, I found the problem - there was a missing newline at the end of my generated code. There are a couple of things that we can do to make this better, though.

1. When stdout / stderr / stdin exceed, say, 256 characters, print them on a new line and indent them. For example:

stdin:
  some input
  is here
  this is multiline
stdout:
  some output
  foo bar
  this is also multiline
stderr: (empty)

2. Use ANSI codes to colorize and make the stdin: / stdout: / stderr: fields bold and colorized, so that they can be easily spotted in a wall of text.
3. (This might be more involved) Print a multi-line colorized diff for stdout and stderr, rather than just the raw text.

[epage]

Whats strange is that the Diff isn't making clear what is different (search for ├── diff). The diff library we are using I think is relying solely on color (which makes it hard to spot whitespace differences) and shows unchanged lines (which bloats the output more).

In cases like this, using something that generates diff like output would be a big help.

I was also thinking it'd be good to get more use of color.

I wish there was a good way to decide what the trim limit should be on the large strings.

[epage]

I've split this out into separate issues in the repo where the code lives. I'm going to go ahead and close this Issue.

[ajeetdsouza]

Thanks!