Let's install phpMyAdmin.
[root@test6 ~]# yum -v install phpMyAdmin
Yum resolves the 'php(language)' dependency with the highest available package, php56u-common, and adds it to the transaction.
--> Processing Dependency: php(language) >= 5.2.17 for package: phpMyAdmin-4.0.10.5-1.el6.noarch
TSINFO: Marking php56u-common-5.6.2-3.ius.centos6.x86_64 as install for phpMyAdmin-4.0.10.5-1.el6.noarch
Yum gets confused trying to resolve the 'php-json' dependency.
--> Processing Dependency: php-json for package: phpMyAdmin-4.0.10.5-1.el6.noarch
Searching pkgSack for dep: php-json
Yum evaluates what is needed if php54-common is used.
looking for ('rtld(GNU_HASH)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
looking for ('libpthread.so.0(GLIBC_2.2.5)(64bit)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
looking for ('libc.so.6(GLIBC_2.8)(64bit)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
looking for ('libz.so.1()(64bit)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
looking for ('libpthread.so.0()(64bit)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
looking for ('libcurl.so.4()(64bit)', None, (None, None, None)) as a requirement of php54-common.x86_64 0:5.4.34-1.ius.centos6 - None
Yum evaluates what is needed if php-common is used.
looking for ('rtld(GNU_HASH)', None, (None, None, None)) as a requirement of php-common.x86_64 0:5.3.3-40.el6_6 - None
looking for ('libc.so.6(GLIBC_2.8)(64bit)', None, (None, None, None)) as a requirement of php-common.x86_64 0:5.3.3-40.el6_6 - None
looking for ('libz.so.1()(64bit)', None, (None, None, None)) as a requirement of php-common.x86_64 0:5.3.3-40.el6_6 - None
looking for ('libcurl.so.4()(64bit)', None, (None, None, None)) as a requirement of php-common.x86_64 0:5.3.3-40.el6_6 - None
Yum evaluates what is needed if php56u-pecl-jsonc is used.
looking for ('php(zend-abi)', 'EQ', ('0', '20131226', '64')) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php(api)', 'EQ', ('0', '20131106', '64')) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('rtld(GNU_HASH)', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php56u-pear', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php56u-pear', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('libc.so.6(GLIBC_2.8)(64bit)', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('/bin/sh', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('/bin/sh', None, (None, None, None)) as a requirement of php56u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
Yum evaluates what is needed if php55u-pecl-jsonc is used.
looking for ('php(zend-abi)', 'EQ', ('0', '20121212', '64')) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php(api)', 'EQ', ('0', '20121113', '64')) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('rtld(GNU_HASH)', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php55u-pear', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('php55u-pear', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('libc.so.6(GLIBC_2.8)(64bit)', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('/bin/sh', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
looking for ('/bin/sh', None, (None, None, None)) as a requirement of php55u-pecl-jsonc.x86_64 0:1.3.6-3.ius.centos6 - None
After evaluating the options, yum decides that php-common is the best choice.
TSINFO: Marking php-common-5.3.3-40.el6_6.x86_64 as install for phpMyAdmin-4.0.10.5-1.el6.noarch
But yum is wrong! It added a package (php-common) to the transaction that has a conflict with a package already in the transaction (php56u-common).
--> Processing Conflict: php56u-common-5.6.2-3.ius.centos6.x86_64 conflicts php-common < 5.6
php56u-common conflicts with php-common-5.3.3-40.el6_6.x86_64
Error: php56u-common conflicts with php-common-5.3.3-40.el6_6.x86_64
But wait, there's more! phpMyAdmin requires php-common, and while yum resolves this to the closest match for the require, there are other packages that provide it.
let's try excluding php-common:
Still some unmet deps... just in case yum stopped resolving the transaction before they were all resolved:
I suspect this would be resolvable with a php56u-php-gettext and php56u-tcpdf + subpackages.