OS detection fails on OSX (Trac #1227)

[phing-issues-importer]

When detecting the OS on a machine running OSX, using the tag both "unix" and "mac" families are matched. Sample build.xml:

<project name="test-os" default="os-setup">
        <target name="os-setup">
        <if>
            <os family="windows" />
            <then>
                <echo>It's windows</echo>
            </then>
        </if>
        <if>
            <os family="mac" />
            <then>
                <echo>It's a mac</echo>
            </then>
        </if>
        <if>
            <os family="unix" />
            <then>
                <echo>It's unix</echo>
            </then>
        </if>
        </target>
</project>

outputs

test-os > os-setup:

     [echo] It's a mac
     [echo] It's unix

BUILD FINISHED

Total time: 0.0901 seconds

Tested on OSX Yosemite.

Migrated from https://www.phing.info/trac/ticket/1227

{
    "status": "new", 
    "changetime": "2015-11-19T09:56:27", 
    "description": "When detecting the OS on a machine running OSX, using the <os/> tag both \"unix\" and \"mac\" families are matched. Sample build.xml:\n\n{{{\n<project name=\"test-os\" default=\"os-setup\">\n        <target name=\"os-setup\">\n        <if>\n            <os family=\"windows\" />\n            <then>\n                <echo>It's windows</echo>\n            </then>\n        </if>\n        <if>\n            <os family=\"mac\" />\n            <then>\n                <echo>It's a mac</echo>\n            </then>\n        </if>\n        <if>\n            <os family=\"unix\" />\n            <then>\n                <echo>It's unix</echo>\n            </then>\n        </if>\n        </target>\n</project>\n}}}\n\noutputs\n\n{{{\ntest-os > os-setup:\n\n     [echo] It's a mac\n     [echo] It's unix\n\nBUILD FINISHED\n\nTotal time: 0.0901 seconds\n}}}\n\nTested on OSX Yosemite.", 
    "reporter": "george.simion@gmail.com", 
    "cc": "", 
    "resolution": "", 
    "_ts": "1447926987000288", 
    "component": "phing-core", 
    "summary": "OS detection fails on OSX", 
    "priority": "tbd", 
    "keywords": "", 
    "version": "2.12.0", 
    "time": "2015-11-18T14:03:41", 
    "milestone": "Backlog", 
    "owner": "mrook", 
    "type": "defect"
}

[siad007]

This is normal behavior - you can be even more specific with conditions:

<condition property="isMacOsButNotMacOsX">
    <and>
      <os family="mac"/>
      <not>
        <os family="unix"/>
      </not>
    </and>
</condition>

[mrook]

Nice example @siad007, I'll add that to the docs.