| 1 | #!/usr/bin/env bash
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| 2 | #
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| 3 | # Pattern for testing if a function has succeeded or failed with set -e:
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| 4 | #
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| 5 | #    SUMMARY: Call it through $0.
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| 6 | # 
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| 7 | # Useful for test frameworks!
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| 8 | #
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| 9 | # Usage:
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| 10 | #   demo/dollar0-errexit.sh <function name>
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| 11 | 
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| 12 | set -o nounset
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| 13 | set -o pipefail
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| 14 | set -o errexit
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| 15 | 
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| 16 | # Should produce TWO lines, not THREE.
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| 17 | # And the whole thing FAILS with exit code 1.
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| 18 | myfunc() {
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| 19 |   echo one
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| 20 |   echo two
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| 21 |   false      # should FAIL here
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| 22 |   echo three
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| 23 | }
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| 24 | 
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| 25 | mypipeline() { myfunc | wc -l; }
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| 26 | 
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| 27 | # Prints three lines because errexit is implicitly disabled.
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| 28 | # It also shouldn't succeed.
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| 29 | bad() {
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| 30 |   if myfunc | wc -l; then
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| 31 |     echo true
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| 32 |   else
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| 33 |     echo false
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| 34 |   fi
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| 35 |   echo status=$?
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| 36 | }
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| 37 | 
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| 38 | # This fixes the behavior.  Prints two lines and fails.
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| 39 | good() {
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| 40 |   if $0 mypipeline; then
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| 41 |     echo true
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| 42 |   else
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| 43 |     echo false
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| 44 |   fi
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| 45 |   echo status=$?
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| 46 | }
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| 47 | 
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| 48 | # This is pretty much what 'bad' is dong.
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| 49 | not-a-fix() {
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| 50 |   set +o errexit
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| 51 |   mypipeline
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| 52 |   local status=$?
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| 53 |   set -o errexit
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| 54 | 
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| 55 |   if test $? -eq 0; then
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| 56 |     echo true
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| 57 |   else
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| 58 |     echo false
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| 59 |   fi
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| 60 |   echo status=$?
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| 61 | }
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| 62 | 
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| 63 | "$@"
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