Re: Bug#72802: make fails to correctly echo commands

[Manoj Srivastava]

Hi,

        [Please retain the CC to address@hidden so
        that the Debian Bug Tracking system can record your input]
         
make 3.79.1 is not correctly echoing commands when they occur in
canned command sequences. Since this is the latest version of make, I
have downgraded to the version from Debian 2.1 (make 3.77), which
never gave me any problems.

Indeed, this contradicts node Sequences: in the info documentation,
which states: 
======================================================================
   In command execution, each line of a canned sequence is treated just
as if the line appeared on its own in the rule, preceded by a tab.  In
particular, `make' invokes a separate subshell for each line.  You can
use the special prefix characters that affect command lines (`@', `-',
and `+') on each line of a canned sequence.  *Note Writing the Commands
in Rules: Commands.  For example, using this canned sequence:

     define frobnicate
     @echo "frobnicating target $@"
     frob-step-1 $< -o address@hidden
     frob-step-2 address@hidden -o $@
     endef

`make' will not echo the first line, the `echo' command.  But it _will_
echo the following two command lines.

   On the other hand, prefix characters on the command line that refers
to a canned sequence apply to every line in the sequence.  So the rule:

     frob.out: frob.in
             @$(frobnicate)

does not echo _any_ commands.  (*Note Command Echoing: Echoing, for a
full explanation of `@'.)
======================================================================



The makefile below demonstrates the problem ("true" should occur twice in the
output, but only occurs once):

        manoj

---
should_not_be_echoed = true This should never be seen on screen
should_be_echoed = true This is correct

define canned_sequence
        @$(should_not_be_echoed)
        $(should_be_echoed)
endef

all : okay faulty

okay :
        @echo "this will be okay"
        @$(should_not_be_echoed)
        $(should_be_echoed)

faulty :
        @echo "this will fail to echo the second command in the canned sequence"
        $(canned_sequence)

-- 
 "Consequences, Schmonsequences, as long as I'm rich." Daffy Duck,
 from Looney Tunes "Ali Baba Bunny" (1957, Chuck Jones)
Manoj Srivastava   <address@hidden>  <http://www.debian.org/%7Esrivasta/>
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