[PATCH v2] completion: fix incorrect bash/zsh string equality check

From: Robert Estelle <robertestelle@gmail.com>

In the basic `[`/`test` command, the string equality operator is a single `=`. The `==` operator is only available in `[[`, which is a bash-ism also supported by zsh.

This mix-up was causing the following completion error in zsh:

(That message refers to the extraneous symbol in `==` ← `=`).

This updates that comparison to use a single `=` inside the basic `[ … ]` test conditional.

Although this fix is inconsistent with the other comparisons in this file, which use `[[ … == … ]]`, and the two expressions are functionally identical in this context, that approach was rejected due to a preference for `[`.

Signed-off-by: Robert Estelle <robertestelle@gmail.com>
---
    completion: Fix incorrect bash/zsh string equality check
    
    v2: This updates the comparison to remove the extraneous = symbol in ==,
    and use the [ … ] conditional instead.
    
    v1: (rejected) updated that comparison to use the extended [[ … ]]
    conditional for consistency with the other checks in this file.
    
    This fixes an error in contrib/completion/git-completion.bash caused by
    the incorrect use of == (vs. single =) inside a basic [/test command.
    Double-equals == should only be used with the extended [[ comparison.
    
    This was causing the following completion error in zsh:
    
    > __git_ls_files_helper:7: = not found
    

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1096%2Frwe%2Ffix-completion-sh-eq-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1096/rwe/fix-completion-sh-eq-v2
Pull-Request: https://github.com/git/git/pull/1096

Range-diff vs v1:

 1:  6fd09347385 ! 1:  eee166c8c99 completion: fix incorrect bash/zsh string equality check
     @@ Commit message
      
          (That message refers to the extraneous symbol in `==` ← `=`).
      
     -    This updates that comparison to use the extended `[[ … ]]` conditional
     -    for consistency with the other checks in this file.
     +    This updates that comparison to use a single `=` inside the
     +    basic `[ … ]` test conditional.
     +
     +    Although this fix is inconsistent with the other comparisons in this
     +    file, which use `[[ … == … ]]`, and the two expressions are functionally
     +    identical in this context, that approach was rejected due to a
     +    preference for `[`.
      
          Signed-off-by: Robert Estelle <robertestelle@gmail.com>
      
     @@ contrib/completion/git-completion.bash: __gitcomp_file ()
       __git_ls_files_helper ()
       {
      -	if [ "$2" == "--committable" ]; then
     -+	if [[ "$2" == "--committable" ]]; then
     ++	if [ "$2" = "--committable" ]; then
       		__git -C "$1" -c core.quotePath=false diff-index \
       			--name-only --relative HEAD -- "${3//\\/\\\\}*"
       	else

 contrib/completion/git-completion.bash | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)