Someone has configured ASF Buildbot for Tomcat with
'echo base.path=../basepath > build.properties'

It resulted in failure at step "extras-commons-logging",
http://ci.apache.org/builders/tomcat-7-trunk/builds/296

Some log file snippets:

[[[
testexist:
     [echo] Testing  for ../basepath/avalon-framework-4.1.5/avalon-framework-4.1.5.jar

downloadfile:

]]]

[[[
extras-commons-logging:
   [gunzip] Expanding /home/buildslave32/slave32/tomcat-7-trunk/basepath/commons-logging-1.1.3/commons-logging-1.1.3-src.tar.gz to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-src.tar
    [untar] Expanding: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-src.tar into /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging
    [mkdir] Created dir: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/src/main/java/org/apache/juli
     [move] Moving 16 files to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/src/main/java/org/apache/juli
     [copy] Copying 1 file to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src
     [copy] Copying 4 files to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src

init:
     [echo] -------- Logging Wrapper Library 1.1.3 --------

prepare:
     [echo] 
     [echo]     Log4j12: log4j-1.2.17.jar
     [echo]     
     [echo]     
     [echo]     LogKit: ../basepath/logkit-1.0.1/logkit-1.0.1.jar
     [echo]     Avalon-Framework: ../basepath/avalon-framework-4.1.5/avalon-framework-4.1.5.jar
     [echo]     
    [mkdir] Created dir: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target
    [mkdir] Created dir: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target/classes
    [mkdir] Created dir: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target/conf
    [mkdir] Created dir: /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target/tests

static:
     [copy] Copying 1 file to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target/conf

discovery:

log4j12-warning:

log4j13-warning:

logkit-warning:
     [echo] 
     [echo]     *** WARNING ***
     [echo]     LogKit not found: Cannot Build LogKitLogger
     [echo]     

jdk1.4-warning:

avalon-framework-warning:
     [echo] 
     [echo]     *** WARNING ***
     [echo]     Avalon-Framework not found: Cannot Build AvalonLogger
     [echo]     

compile-non-log4j:
    [javac] /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/build2.xml:362: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
    [javac] Compiling 11 source files to /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/target/classes
    [javac] /home/buildslave32/slave32/tomcat-7-trunk/build/output/extras/logging/commons-logging-1.1.3-src/src/main/java/org/apache/juli/logging/impl/ServletContextCleaner.java:23: package javax.servlet does not exist
    [javac] import javax.servlet.ServletContextEvent;
    [javac]                     ^
]]]

So,
1. avalon-framework-4.1.5.jar was present and has not been downloaded
2. commons-logging build script failed to detect it,
with "Avalon-Framework not found: Cannot Build AvalonLogger"

Compilation is performed by 

    <ant antfile="${tomcat.extras}/logging/commons-logging-${commons-logging.version}-src/build2.xml"
         dir="${tomcat.extras}/logging/commons-logging-${commons-logging.version}-src"
         target="compile" />

So dir is a different directory.


Fix
====
I was able to fix this issue by adding inheritAll="false" to the above <ant> command.