As for more concrete guidelines, just imitate the existing code
(this is a good guideline, no matter which project you are
-contributing to). But if you must have a list of rules,
-here they are.
+contributing to). It is always preferable to match the _local_
+convention. New code added to git suite is expected to match
+the overall style of existing code. Modifications to existing
+code is expected to match the style the surrounding code already
+uses (even if it doesn't match the overall style of existing code).
+
+But if you must have a list of rules, here they are.
For shell scripts specifically (not exhaustive):
properly nests. It should have been the way Bourne spelled
it from day one, but unfortunately isn't.
- - We use ${parameter-word} and its [-=?+] siblings, and their
- colon'ed "unset or null" form.
+ - We use POSIX compliant parameter substitutions and avoid bashisms;
+ namely:
- - We use ${parameter#word} and its [#%] siblings, and their
- doubled "longest matching" form.
+ - We use ${parameter-word} and its [-=?+] siblings, and their
+ colon'ed "unset or null" form.
- - We use Arithmetic Expansion $(( ... )).
+ - We use ${parameter#word} and its [#%] siblings, and their
+ doubled "longest matching" form.
+
+ - No "Substring Expansion" ${parameter:offset:length}.
- - No "Substring Expansion" ${parameter:offset:length}.
+ - No shell arrays.
- - No shell arrays.
+ - No strlen ${#parameter}.
- - No strlen ${#parameter}.
+ - No pattern replacement ${parameter/pattern/string}.
- - No regexp ${parameter/pattern/string}.
+ - We use Arithmetic Expansion $(( ... )).
+
+ - Inside Arithmetic Expansion, spell shell variables with $ in front
+ of them, as some shells do not grok $((x)) while accepting $(($x))
+ just fine (e.g. dash older than 0.5.4).
- We do not use Process Substitution <(list) or >(list).
used in the git core command set (unless your command is clearly
separate from it, such as an importer to convert random-scm-X
repositories to git).
+
+ - When we pass <string, length> pair to functions, we should try to
+ pass them in that order.