Since commit v3.9.0-rc1~58^2 (find_package: shorten output for missing
package in config mode, 2017-05-09) we print only the one line

    - Could NOT find Foo (missing: Foo_DIR)

when package Foo cannot be found in CONFIG mode and it is not REQUIRED.
However, in the case that package configuration files were found but not
used, this one line message leaves out important information.  This can
happen when a package configuration file sets `Foo_FOUND` to `FALSE` or
when its package version file does not match the requested version.
Restore the longer message in these cases.  Otherwise a seemingly valid
explicit `Foo_DIR` setting appears to be silently ignored even if it was
considered.

Fixes: #17029

Christoph Grüninger authored May 09, 2017 and Brad King committed May 23, 2017

If CONFIG or MODULE is given and the package is not REQUIRED,
output a one-liner instead of the full warning.

Update Tests/RunCMake/find_package expected output to match.

The new PackageRoot search path group allows the PackageName_ROOT cmake
and environment variables to be used as search prefixes for all find_*
commands called from within a find module

Automate with:

git grep -l '#include <cm_' -- Source \
  | xargs sed -i 's/#include <\(cm_.*\)>/#include "\1"/g'

git grep -l '#include <cmsys/' -- Source \
  | xargs sed -i 's/#include <\(cmsys\/.*\)>/#include "\1"/g'

git grep -l '#include <cm[A-Z]' -- Source \
  | xargs sed -i 's/#include <\(cm[A-Z].*\)>/#include "\1"/g'

Comments that indicate a special include order is necessary because
GetCurrentDirectory might get redefined are outdated.  Remove those
outdated comments and use the normal ordering of includes.

Steven Newbury authored Feb 27, 2017 and Brad King committed Mar 07, 2017

Detect x32-abi through CMakeCompilerABI infrastruture and use this
information at runtime to determine the correct library paths with
`FIND_LIBRARY_USE_LIBX32_PATHS`.

Fixes: #15994

Clang-tidy reports some issues only from the currently compiled source
file and its associated header file.  Separating the compilation of
commands exposed some clang-tidy issues that were not reported previously.
Fix them.

Include it in dependents which have previously relied on it
transitively.

Port dependent code to the change.

Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool.  Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience.  Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.

Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices.  It also references version control
history for more precise information.  Therefore we no longer need to spell
out the list of Contributors in each source file notice.

Replace CMake per-source copyright/license notice headers with a short
description of the license and lin...

Pierluigi Taddei authored Sep 08, 2016 and Brad King committed Sep 15, 2016

Add `CMAKE_FIND_PACKAGE_SORT_{ORDER,DIRECTION}` variables to specify
sort order and direction.

When multiple package with the same name have been found in the same
location sorting option can be used to force a specific version to be
loaded (e.g. libA_1.12.0 instead of libA_1.1.0).  Currently sorting by
NAME and by NATURAL order have been implemented.

Natural ordering makes use of the `strverscmp(3)` ordering.

Silvio Traversaro authored Aug 20, 2016 and Brad King committed Aug 24, 2016

Find packages that install their cmake package configuration files in
`lib/cmake/<name>` when they are installed in the default Windows
CMAKE_INSTALL_PREFIX, `C:/Program Files/<name>`.

Closes: #16212

Replace use of cmsys::auto_ptr with a CM_AUTO_PTR macro that maps to
our own implementation adopted from the KWSys auto_ptr implementation.
Later we may be able to map CM_AUTO_PTR to std::auto_ptr on compilers
that do not warn about it.

Automate the client site conversions:

    git grep -l auto_ptr -- Source/ | grep -v Source/kwsys/ | xargs sed -i \
      's|cmsys::auto_ptr|CM_AUTO_PTR|;s|cmsys/auto_ptr.hxx|cm_auto_ptr.hxx|'

Fixes #15252.

Daniel Scharrer authored Jun 10, 2016 and Brad King committed Jun 10, 2016

Add a ``FIND_LIBRARY_USE_LIB32_PATHS`` global property analogous to the
``FIND_LIBRARY_USE_LIB64_PATHS`` property.  This helps find commands on
multilib systems that use ``lib32`` directories and either do not have
``lib`` symlinks or point ``lib`` to ``lib64``.

Kitware Robot authored May 16, 2016 and Brad King committed May 16, 2016

Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.

* If you reached this commit for a line in `git blame`, re-run the blame
  operation starting at the parent of this commit to see older history
  for the content.

* See the parent commit for instructions to rebase a change across this
  style transition commit.

Modern editors provide plenty of ways to visually separate functions.
Drop the explicit comments that previously served this purpose.
Use the following command to automate the change:

    $ git ls-files -z -- \
        "*.c" "*.cc" "*.cpp" "*.cxx" "*.h" "*.hh" "*.hpp" "*.hxx" |
      egrep -z -v "^Source/cmCommandArgumentLexer\." |
      egrep -z -v "^Source/cmCommandArgumentParser(\.y|\.cxx|Tokens\.h)" |
      egrep -z -v "^Source/cmDependsJavaLexer\." |
      egrep -z -v "^Source/cmDependsJavaParser(\.y|\.cxx|Tokens\.h)" |
      egrep -z -v "^Source/cmExprLexer\." |
      egrep -z -v "^Source/cmExprParser(\.y|\.cxx|Tokens\.h)" |
      egrep -z -v "^Source/cmFortranLexer\." |
      egrep -z -v "^Source/cmFortranParser(\.y|\.cxx|Tokens\.h)" |
      egrep -z -v "^Source/cmListFileLexer\." |
      egrep -z -v "^Source/cm_sha2" |
      egrep -z -v "^Source/(kwsys|CursesDialog/form)/" |
      egrep -z -v "^Utilities/(KW|cm).*/" |
      xargs -0 sed -i '/^\(\/\/---*\|\/\*---*\*\/\)$/ {d;}'

This avoids modifying third-party sources and generated sources.

The clang-format tool can do a good job formatting most code, but
well-organized streaming blocks are best left manually formatted.

Find blocks of the form

    os <<
      "...\n"
      "...\n"
      ;

using the command

    $ git ls-files -z -- Source |
      egrep -v -z '^Source/kwsys/' |
      xargs -0 pcregrep -M --color=always -B 1 -A 1 -n \
        '<<[^\n]*\n(^ *("[^\n]*("|<<|;)$|;)\n){2,}'

Find blocks of the form

    os << "...\n"
       << "...\n"
       << "...\n";

using the command

    $ git ls-files -z -- Source |
      egrep -v -z '^Source/kwsys/' |
      xargs -0 pcregrep -M --color=always -B 1 -A 1 -n \
        '<<[^\n]*\n(^ *<<[^\n]*(\\n"|<<|;)$\n){2,}'

Surround such blocks with the pair

    /* clang-format off */
    ...
    /* clang-format on */

in order to protect them from update by clang-format.  Use the C-style
`/*...*/` comments instead of C++-style `//...` comments in order to
prevent them from ever being swallowed by re-formatting of surrounding
comments.

Sort include directives within each block (separated by a blank line) in
lexicographic order (except to prioritize `sys/types.h` first).  First
run `clang-format` with the config file:

    ---
    SortIncludes: false
    ...

Commit the result temporarily.  Then run `clang-format` again with:

    ---
    SortIncludes: true
    IncludeCategories:
      - Regex:    'sys/types.h'
        Priority: -1
    ...

Commit the result temporarily.  Start a new branch and cherry-pick the
second commit.  Manually resolve conflicts to preserve indentation of
re-ordered includes.  This cleans up the include ordering without
changing any other style.

Use the following command to run `clang-format`:

    $ git ls-files -z -- \
        '*.c' '*.cc' '*.cpp' '*.cxx' '*.h' '*.hh' '*.hpp' '*.hxx' |
      egrep -z -v '(Lexer|Parser|ParserHelper)\.' |
      egrep -z -v '^Source/cm_sha2' |
      egrep -z -v '^Source/(kwsys|CursesDialog/form)/' |
      egrep -z -v '^Utilities/(KW|cm).*/' |
      egrep -z -v '^Tests/Module/GenerateExportHeader' |
      egrep -z -v '^Tests/RunCMake/CommandLine/cmake_depends/test_UTF-16LE.h' |
      xargs -0 clang-format -i

This selects source files that do not come from a third-party.

Inspired-by: Daniel Pfeifer <daniel@pfeifer-mail.de>

Chuck Atkins authored Sep 09, 2015 and Brad King committed Sep 14, 2015

Refactoring in the topic merged by commit v3.2.0-rc1~400 (Merge topic
'refactor-search-path-construction', 2014-11-13) introduced a bug that
filters out duplicate paths in an incorrect order.  Restore the search
path to its documented order even when duplicate paths are present.

Reported-by: Marc CHEVRIER <marc.chevrier@sap.com>

We no longer need this compatibility layer for the compilers we support.

The find_package command, on Windows, has always searched build trees
recently visited by cmake-gui (or CMakeSetup at one time).  This was
done when the command was created with the intention of simplifying
workflows involving building multiple dependent projects.  However,
this behavior depends on recent developer interaction and therefore
can create different find results based on transient system states.
It can lead to surprising results and user confusion.

Since this behavior was first added CMake has gained many more search
options, better error messages when a package is not found, and a
package registry.  The latter in particular allows projects to make
their build trees available for dependent projects to find without
user intervention.  Therefore the originally intended workflow can
be achieved in other, more stable ways.

After the above evoluion of find_package we have now decided that
the magic search-where-cmake-gui-was behavior does more harm than
good.  Drop it.  We do not need a policy for this behavior change
because it only affects interactive use.

Match the names used in cmake code.

Such files are delegates from other files, and so they set the
CMAKE_PARENT_LIST_FILE to the originator.  They also may set a
policy scope.

There is no reason for this to be a responsibility of
ReadListFile.  Additionally, the only user of it already computes
it itself.