Dale, thanks for explaining. So basically the behavior is as documented (not a bug), but the design decision was poor:
declare a a=b has a different semantic as declare a=b which I consider to be bad. Ulrich >>> "Dale R. Worley" <wor...@alum.mit.edu> schrieb am 02.12.2022 um 17:39 in Nachricht <878rjpahfz....@hobgoblin.ariadne.com>: > Chet Ramey <chet.ra...@case.edu> writes: >> On 12/2/22 5:28 AM, Ulrich Windl wrote: >>> Surprisingly "declare XXX=$(false);echo $?" outputs "0" (not "1") >>> There is no indication in the manual page that "declare" ignores the >>exit code of commands being executed to set values. >> >> Why do you think it should? `declare' has a well-defined return status. > > There it is, end of "SIMPLE COMMAND EXPANSION": > > If there is a command name left after expansion, execution proceeds > as > described below. Otherwise, the command exits. If one of the > expan‐ > sions contained a command substitution, the exit status of the > command > is the exit status of the last command substitution performed. > If > there were no command substitutions, the command exits with a status > of > zero. > > and: > > declare [-aAfFgiIlnrtux] [-p] [name[=value] ...] > typeset [-aAfFgiIlnrtux] [-p] [name[=value] ...] > [...] > The return value > is 0 unless an invalid option is encountered, an attempt is > made > to define a function using ``-f foo=bar'', an attempt is made > to > assign a value to a readonly variable, an attempt is made to > as‐ > sign a value to an array variable without using the compound > as‐ > signment syntax (see Arrays above), one of the names is not > a > valid shell variable name, an attempt is made to turn off > read‐ > only status for a readonly variable, an attempt is made to > turn > off array status for an array variable, or an attempt is made > to > display a non-existent function with -f. > > If you input "XXX=$(false)", there isn't a command name, it's a sequence > of assignments, and "the exit status of the command is the exit status > of the last command substitution performed". But if you input "declare > XXX=$(false)", you're executing the "declare" command, and the exit > status doesn't depend on the command substitution. > > Dale
