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Updated SC2155 (markdown)

Mingye Wang
2020-05-12 12:50:30 +08:00
parent 10c76c698f
commit 93d4e6f5d9
1 changed files with 7 additions and 7 deletions
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14
SC2155.md

@@ -6,20 +6,20 @@
export foo="$(mycmd)" export foo="$(mycmd)"
``` ```
### Correct code: #### Correct code:
```sh ```sh
foo="$(mycmd)" foo="$(mycmd)"
export foo export foo
``` ```
### Rationale: #### Rationale:
In the original code, the return value of `mycmd` is ignored, and `export` will instead always return true. This may prevent conditionals, `set -e` and traps from working correctly. In the original code, the return value of `mycmd` is ignored, and `export` will instead always return true. This may prevent conditionals, `set -e` and traps from working correctly.
When first marked for export and assigned separately, the return value of the assignment will be that of `mycmd`. This avoids the problem. When first marked for export and assigned separately, the return value of the assignment will be that of `mycmd`. This avoids the problem.
### Exceptions: #### Exceptions:
If you intend to ignore the return value of an assignment, you can either ignore this warning or use If you intend to ignore the return value of an assignment, you can either ignore this warning or use
@@ -36,14 +36,14 @@ Shellcheck does not warn about `export foo=bar` because `bar` is a literal and n
local foo="$(mycmd)" local foo="$(mycmd)"
``` ```
### Correct code: #### Correct code:
```sh ```sh
local foo local foo
foo=$(mycmd) foo=$(mycmd)
``` ```
### Rationale #### Rationale
The exit status of the command is overridden by the exit status of the creation of the local variable. For example: The exit status of the command is overridden by the exit status of the creation of the local variable. For example:
@@ -59,14 +59,14 @@ foo
readonly foo="$(mycmd)" readonly foo="$(mycmd)"
``` ```
### Correct code: #### Correct code:
```sh ```sh
foo="$(mycmd)" foo="$(mycmd)"
readonly foo readonly foo
``` ```
### Word splitting and quoting issue with dash, maybe others #### Word splitting and quoting issue with dash, maybe others
A serious quoting problem with dash is another reason to declare and assign separately. Dash is the [default, `/bin/sh` shell on Ubuntu](https://wiki.ubuntu.com/DashAsBinSh). More specifically, dash version 0.5.8-2.10 and others cannot run this code: A serious quoting problem with dash is another reason to declare and assign separately. Dash is the [default, `/bin/sh` shell on Ubuntu](https://wiki.ubuntu.com/DashAsBinSh). More specifically, dash version 0.5.8-2.10 and others cannot run this code:
```sh ```sh