Showing 405 of 405 total issues
Trailing punctuation in header Open
## How is Backbone used?
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MD026 - Trailing punctuation in header
Tags: headers
Aliases: no-trailing-punctuation
Parameters: punctuation (string; default ".,;:!?")
This rule is triggered on any header that has a punctuation character as the last character in the line:
# This is a header.
To fix this, remove any trailing punctuation:
# This is a header
Note: The punctuation parameter can be used to specify what characters class
as punctuation at the end of the header. For example, you can set it to
'.,;:!'
to allow headers with question marks in them, such as might be used
in an FAQ.
Line too long (89 > 79 characters) Open
CACHES['eregs_longterm_cache']['BACKEND'] = 'django.core.cache.backends.dummy.DummyCache'
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Limit all lines to a maximum of 79 characters.
There are still many devices around that are limited to 80 character
lines; plus, limiting windows to 80 characters makes it possible to
have several windows side-by-side. The default wrapping on such
devices looks ugly. Therefore, please limit all lines to a maximum
of 79 characters. For flowing long blocks of text (docstrings or
comments), limiting the length to 72 characters is recommended.
Reports error E501.
Ambiguous variable name 'l' Open
suffix_sortable = [make_label_sortable(l)[0] for l in suffix]
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Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Ambiguous variable name 'l' Open
def _not_markerless(l):
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Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Lists should be surrounded by blank lines Open
- A view is created for a piece of content. The view calls [get()](regulations/static/regulations/js/source/models/meta-model.js#L60) on its model.
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MD032 - Lists should be surrounded by blank lines
Tags: bullet, ul, ol, blank_lines
Aliases: blanks-around-lists
This rule is triggered when lists (of any kind) are either not preceded or not followed by a blank line:
Some text
* Some
* List
1. Some
2. List
Some text
To fix this, ensure that all lists have a blank line both before and after (except where the block is at the beginning or end of the document):
Some text
* Some
* List
1. Some
2. List
Some text
Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse lists that don't have blank lines before and after them.
Note: List items without hanging indents are a violation of this rule; list items with hanging indents are okay:
* This is
not okay
* This is
okay
Lists should be surrounded by blank lines Open
- The model constructs a URL to request data from the server and makes the AJAX request and creates a Promise object
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MD032 - Lists should be surrounded by blank lines
Tags: bullet, ul, ol, blank_lines
Aliases: blanks-around-lists
This rule is triggered when lists (of any kind) are either not preceded or not followed by a blank line:
Some text
* Some
* List
1. Some
2. List
Some text
To fix this, ensure that all lists have a blank line both before and after (except where the block is at the beginning or end of the document):
Some text
* Some
* List
1. Some
2. List
Some text
Rationale: Aside from aesthetic reasons, some parsers, including kramdown, will not parse lists that don't have blank lines before and after them.
Note: List items without hanging indents are a violation of this rule; list items with hanging indents are okay:
* This is
not okay
* This is
okay
Ambiguous variable name 'l' Open
lines = [l for l in lines if l.strip()]
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Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Quote this to prevent word splitting. Open
if [ ! $(npm_package_is_installed less2sass) ]
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Quote this to prevent word splitting
Problematic code:
ls -l $(getfilename)
Correct code:
# getfilename outputs 1 file
ls -l "$(getfilename)"
# getfilename outputs multiple files, linefeed separated
getfilename | while IFS='' read -r line
do
ls -l "$line"
done
Rationale:
When command expansions are unquoted, word splitting and globbing will occur. This often manifests itself by breaking when filenames contain spaces.
Trying to fix it by adding quotes or escapes to the data will not work. Instead, quote the command substitution itself.
If the command substitution outputs multiple pieces of data, use a loop instead.
Exceptions
In rare cases you actually want word splitting, such as in
gcc $(pkg-config --libs openssl) client.c
This is because pkg-config
outputs -lssl -lcrypto
, which you want to break up by spaces into -lssl
and -lcrypto
. An alternative is to put the variables to an array and expand it:
args=( $(pkg-config --libs openssl) )
gcc "${args[@]}" client.c
The power of using an array becomes evident when you want to combine, for example, the command result with user-provided arguments:
compile () {
args=( $(pkg-config --libs openssl) "${@}" )
gcc "${args[@]}" client.c
}
compile -DDEBUG
+ gcc -lssl -lcrypto -DDEBUG client.c
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Use 'cd ... || exit' or 'cd ... || return' in case cd fails. Open
cd module
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Use cd ... || exit in case cd fails.
Problematic code:
cd generated_files
rm -r *.c
func(){
cd foo
do_something
}
Correct code:
cd generated_files || exit
rm -r *.c
# For functions, you may want to use return:
func(){
cd foo || return
do_something
}
Rationale:
cd
can fail for a variety of reasons: misspelled paths, missing directories, missing permissions, broken symlinks and more.
If/when it does, the script will keep going and do all its operations in the wrong directory. This can be messy, especially if the operations involve creating or deleting a lot of files.
To avoid this, make sure you handle the cases when cd
fails. Ways to do this include
-
cd foo || exit
as suggested to just abort immediately -
if cd foo; then echo "Ok"; else echo "Fail"; fi
for custom handling -
<(cd foo && cmd)
as an alternative to<(cd foo || exit; cmd)
in<(..)
,$(..)
or( )
Exceptions:
ShellCheck does not give this warning when cd
is on the left of a ||
or &&
, or the condition of a if
, while
or until
loop. Having a set -e
command anywhere in the script will disable this message, even though it won't necessarily prevent the issue.
If you are accounting for cd
failures in a way shellcheck doesn't realize, you can disable this message with a [[directive]].
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Use 'cd ... || exit' or 'cd ... || return' in case cd fails. Open
cd ../
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Use cd ... || exit in case cd fails.
Problematic code:
cd generated_files
rm -r *.c
func(){
cd foo
do_something
}
Correct code:
cd generated_files || exit
rm -r *.c
# For functions, you may want to use return:
func(){
cd foo || return
do_something
}
Rationale:
cd
can fail for a variety of reasons: misspelled paths, missing directories, missing permissions, broken symlinks and more.
If/when it does, the script will keep going and do all its operations in the wrong directory. This can be messy, especially if the operations involve creating or deleting a lot of files.
To avoid this, make sure you handle the cases when cd
fails. Ways to do this include
-
cd foo || exit
as suggested to just abort immediately -
if cd foo; then echo "Ok"; else echo "Fail"; fi
for custom handling -
<(cd foo && cmd)
as an alternative to<(cd foo || exit; cmd)
in<(..)
,$(..)
or( )
Exceptions:
ShellCheck does not give this warning when cd
is on the left of a ||
or &&
, or the condition of a if
, while
or until
loop. Having a set -e
command anywhere in the script will disable this message, even though it won't necessarily prevent the issue.
If you are accounting for cd
failures in a way shellcheck doesn't realize, you can disable this message with a [[directive]].
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Use 'cd ... || exit' or 'cd ... || return' in case cd fails. Open
cd ../../scss
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Use cd ... || exit in case cd fails.
Problematic code:
cd generated_files
rm -r *.c
func(){
cd foo
do_something
}
Correct code:
cd generated_files || exit
rm -r *.c
# For functions, you may want to use return:
func(){
cd foo || return
do_something
}
Rationale:
cd
can fail for a variety of reasons: misspelled paths, missing directories, missing permissions, broken symlinks and more.
If/when it does, the script will keep going and do all its operations in the wrong directory. This can be messy, especially if the operations involve creating or deleting a lot of files.
To avoid this, make sure you handle the cases when cd
fails. Ways to do this include
-
cd foo || exit
as suggested to just abort immediately -
if cd foo; then echo "Ok"; else echo "Fail"; fi
for custom handling -
<(cd foo && cmd)
as an alternative to<(cd foo || exit; cmd)
in<(..)
,$(..)
or( )
Exceptions:
ShellCheck does not give this warning when cd
is on the left of a ||
or &&
, or the condition of a if
, while
or until
loop. Having a set -e
command anywhere in the script will disable this message, even though it won't necessarily prevent the issue.
If you are accounting for cd
failures in a way shellcheck doesn't realize, you can disable this message with a [[directive]].
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Invalid escape sequence '\s' Open
SECTION_TITLE_REGEX = re.compile(u'^§+ ([-.\w]*)[\s-]*(.*)', re.UNICODE)
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Invalid escape sequences are deprecated in Python 3.6.
Okay: regex = r'\.png$'
W605: regex = '\.png$'
Ambiguous variable name 'l' Open
label_ops.extend(DiffApplier._LabelOp(l, op) for l in labels)
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Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Use $(..) instead of legacy ..
. Open
FUTURE=`date --date="1 month" +"%Y-%m-%d"`
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Use $(STATEMENT) instead of legacy `STATEMENT`
Problematic code
echo "Current time: `date`"
Correct code
echo "Current time: $(date)"
Rationale
Backtick command substitution `STATEMENT`
is legacy syntax with several issues.
- It has a series of undefined behaviors related to quoting in POSIX.
- It imposes a custom escaping mode with surprising results.
- It's exceptionally hard to nest.
$(STATEMENT)
command substitution has none of these problems, and is therefore strongly encouraged.
Exceptions
None.
See also
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Double quote to prevent globbing and word splitting. Open
curl -X PUT http://localhost:8080/$TAIL -d @$TAIL
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Double quote to prevent globbing and word splitting.
Problematic code:
echo $1
for i in $*; do :; done # this done and the next one also applies to expanding arrays.
for i in $@; do :; done
Correct code:
echo "$1"
for i in "$@"; do :; done # or, 'for i; do'
Rationale
The first code looks like "print the first argument". It's actually "Split the first argument by IFS (spaces, tabs and line feeds). Expand each of them as if it was a glob. Join all the resulting strings and filenames with spaces. Print the result."
The second one looks like "iterate through all arguments". It's actually "join all the arguments by the first character of IFS (space), split them by IFS and expand each of them as globs, and iterate on the resulting list". The third one skips the joining part.
Quoting variables prevents word splitting and glob expansion, and prevents the script from breaking when input contains spaces, line feeds, glob characters and such.
Strictly speaking, only expansions themselves need to be quoted, but for stylistic reasons, entire arguments with multiple variable and literal parts are often quoted as one:
$HOME/$dir/dist/bin/$file # Unquoted (bad)
"$HOME"/"$dir"/dist/bin/"$file" # Minimal quoting (good)
"$HOME/$dir/dist/bin/$file" # Canonical quoting (good)
When quoting composite arguments, make sure to exclude globs and brace expansions, which lose their special meaning in double quotes: "$HOME/$dir/src/*.c"
will not expand, but "$HOME/$dir/src"/*.c
will.
Note that $( )
starts a new context, and variables in it have to be quoted independently:
echo "This $variable is quoted $(but this $variable is not)"
echo "This $variable is quoted $(and now this "$variable" is too)"
Exceptions
Sometimes you want to split on spaces, like when building a command line:
options="-j 5 -B"
make $options file
Just quoting this doesn't work. Instead, you should have used an array (bash, ksh, zsh):
options=(-j 5 -B) # ksh: set -A options -- -j 5 -B
make "${options[@]}" file
or a function (POSIX):
make_with_flags() { make -j 5 -B "$@"; }
make_with_flags file
To split on spaces but not perform glob expansion, Posix has a set -f
to disable globbing. You can disable word splitting by setting IFS=''
.
Similarly, you might want an optional argument:
debug=""
[[ $1 == "--trace-commands" ]] && debug="-x"
bash $debug script
Quoting this doesn't work, since in the default case, "$debug"
would expand to one empty argument while $debug
would expand into zero arguments. In this case, you can use an array with zero or one elements as outlined above, or you can use an unquoted expansion with an alternate value:
debug=""
[[ $1 == "--trace-commands" ]] && debug="yes"
bash ${debug:+"-x"} script
This is better than an unquoted value because the alternative value can be properly quoted, e.g. wget ${output:+ -o "$output"}
.
As always, this warning can be [[ignore]]d on a case-by-case basis.
this is especially relevant when BASH many not be available for the array work around. For example, use in eval or in command options where script has total control of the variables...
FLAGS="-av -e 'ssh -x' --delete --delete-excluded"
...
# shellcheck disable=SC2086
eval rsync $FLAGS ~/dir remote_host:dir
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Ambiguous variable name 'l' Open
layer_names = [l for l in layer_names if l in DATA_LAYERS]
- Read upRead up
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Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Ambiguous variable name 'l' Open
sortable = [make_label_sortable(l)[0] for l in label]
- Read upRead up
- Exclude checks
Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Ambiguous variable name 'l' Open
for l in toc_element['index'])
- Read upRead up
- Exclude checks
Never use the characters 'l', 'O', or 'I' as variable names.
In some fonts, these characters are indistinguishable from the
numerals one and zero. When tempted to use 'l', use 'L' instead.
Okay: L = 0
Okay: o = 123
Okay: i = 42
E741: l = 0
E741: O = 123
E741: I = 42
Variables can be bound in several other contexts, including class
and function definitions, 'global' and 'nonlocal' statements,
exception handlers, and 'with' and 'for' statements.
In addition, we have a special handling for function parameters.
Okay: except AttributeError as o:
Okay: with lock as L:
Okay: foo(l=12)
Okay: for a in foo(l=12):
E741: except AttributeError as O:
E741: with lock as l:
E741: global I
E741: nonlocal l
E741: def foo(l):
E741: def foo(l=12):
E741: l = foo(l=12)
E741: for l in range(10):
E742: class I(object):
E743: def l(x):
Don't use ls | grep. Use a glob or a for loop with a condition to allow non-alphanumeric filenames. Open
ls /usr/local/lib/node_modules | grep $1 >/dev/null 2>&1 || { local return_=0; }
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- Exclude checks
Don't use ls | grep. Use a glob or a for loop with a condition to allow non-alphanumeric filenames.
Problematic code:
ls /directory | grep target_file_pattern
Correct code:
ls /directory/target_file_pattern
Rationale:
Matching non-alphanumeric characters with grep may require escaping. Typically it is cleaner to use the built in pattern matching or another command like find
Exceptions:
None
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.
Use ./*glob* or -- *glob* so names with dashes won't become options. Open
rm *.bak **/*.bak
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Use ./*glob* or -- *glob* so names with dashes won't become options.
Problematic code:
rm *
Correct code:
rm ./*
or
rm -- *
Rationale
Since files and arguments are strings passed the same way, programs can't properly determine which is which, and rely on dashes to determine what's what.
A file named -f
(touch -- -f
) will not be deleted by the problematic code. It will instead be interpreted as a command line option, and rm
will even report success.
Using ./*
will instead cause the glob to be expanded into ./-f
, which no program will treat as an option.
Similarly, --
by convention indicates the end of options, and nothing after it will be treated like flags (except for some programs possibly still special casing -
as e.g. stdin).
Note that changing *
to ./*
in GNU Tar parameters will add ./
prefix to path names in the created archive. This may cause subtle problems (eg. to search for a specific file in archive, the ./
prefix must be specified as well). So using -- *
is a safer fix for GNU Tar commands.
For more information, see "Filenames and Pathnames in Shell: How to do it Correctly".
Notice
Original content from the ShellCheck https://github.com/koalaman/shellcheck/wiki.