CMake/Source/cmPolicies.cxx
Brad King c332e0bf3c ENH: Isolate policy changes in included scripts
Isolation of policy changes inside scripts is important for protecting
the including context.  This teaches include() and find_package() to
imply a cmake_policy(PUSH) and cmake_policy(POP) around the scripts they
load, with a NO_POLICY_SCOPE option to disable the behavior.  This also
creates CMake Policy CMP0011 to provide compatibility.  See issue #8192.
2009-01-22 13:18:40 -05:00

684 lines
27 KiB
C++

#include "cmPolicies.h"
#include "cmake.h"
#include "cmMakefile.h"
#include "cmSourceFile.h"
#include "cmVersion.h"
#include <map>
#include <set>
#include <queue>
#include <assert.h>
const char* cmPolicies::PolicyStatusNames[] = {
"OLD", "WARN", "NEW", "REQUIRED_IF_USED", "REQUIRED_ALWAYS"
};
class cmPolicy
{
public:
cmPolicy(cmPolicies::PolicyID iD,
const char *idString,
const char *shortDescription,
const char *longDescription,
unsigned int majorVersionIntroduced,
unsigned int minorVersionIntroduced,
unsigned int patchVersionIntroduced,
cmPolicies::PolicyStatus status)
{
if (!idString || !shortDescription || ! longDescription)
{
cmSystemTools::Error("Attempt to define a policy without "
"all parameters being specified!");
return;
}
this->ID = iD;
this->IDString = idString;
this->ShortDescription = shortDescription;
this->LongDescription = longDescription;
this->MajorVersionIntroduced = majorVersionIntroduced;
this->MinorVersionIntroduced = minorVersionIntroduced;
this->PatchVersionIntroduced = patchVersionIntroduced;
this->Status = status;
}
std::string GetVersionString()
{
cmOStringStream error;
error << this->MajorVersionIntroduced << "." <<
this->MinorVersionIntroduced << "." <<
this->PatchVersionIntroduced;
return error.str();
}
bool IsPolicyNewerThan(unsigned int majorV,
unsigned int minorV,
unsigned int patchV)
{
if (majorV < this->MajorVersionIntroduced)
{
return true;
}
if (majorV > this->MajorVersionIntroduced)
{
return false;
}
if (minorV < this->MinorVersionIntroduced)
{
return true;
}
if (minorV > this->MinorVersionIntroduced)
{
return false;
}
return (patchV < this->PatchVersionIntroduced);
}
cmPolicies::PolicyID ID;
std::string IDString;
std::string ShortDescription;
std::string LongDescription;
unsigned int MajorVersionIntroduced;
unsigned int MinorVersionIntroduced;
unsigned int PatchVersionIntroduced;
cmPolicies::PolicyStatus Status;
};
cmPolicies::cmPolicies()
{
// define all the policies
this->DefinePolicy(
CMP0000, "CMP0000",
"A minimum required CMake version must be specified.",
"CMake requires that projects specify the version of CMake to which "
"they have been written. "
"This policy has been put in place so users trying to build the project "
"may be told when they need to update their CMake. "
"Specifying a version also helps the project build with CMake versions "
"newer than that specified. "
"Use the cmake_minimum_required command at the top of your main "
" CMakeLists.txt file:\n"
" cmake_minimum_required(VERSION <major>.<minor>)\n"
"where \"<major>.<minor>\" is the version of CMake you want to support "
"(such as \"2.6\"). "
"The command will ensure that at least the given version of CMake is "
"running and help newer versions be compatible with the project. "
"See documentation of cmake_minimum_required for details.\n"
"Note that the command invocation must appear in the CMakeLists.txt "
"file itself; a call in an included file is not sufficient. "
"However, the cmake_policy command may be called to set policy "
"CMP0000 to OLD or NEW behavior explicitly. "
"The OLD behavior is to silently ignore the missing invocation. "
"The NEW behavior is to issue an error instead of a warning. "
"An included file may set CMP0000 explicitly to affect how this "
"policy is enforced for the main CMakeLists.txt file.",
2,6,0, cmPolicies::WARN
);
this->DefinePolicy(
CMP0001, "CMP0001",
"CMAKE_BACKWARDS_COMPATIBILITY should no longer be used.",
"The OLD behavior is to check CMAKE_BACKWARDS_COMPATIBILITY and present "
"it to the user. "
"The NEW behavior is to ignore CMAKE_BACKWARDS_COMPATIBILITY "
"completely.\n"
"In CMake 2.4 and below the variable CMAKE_BACKWARDS_COMPATIBILITY was "
"used to request compatibility with earlier versions of CMake. "
"In CMake 2.6 and above all compatibility issues are handled by policies "
"and the cmake_policy command. "
"However, CMake must still check CMAKE_BACKWARDS_COMPATIBILITY for "
"projects written for CMake 2.4 and below.",
2,6,0, cmPolicies::WARN
);
this->DefinePolicy(
CMP0002, "CMP0002",
"Logical target names must be globally unique.",
"Targets names created with "
"add_executable, add_library, or add_custom_target "
"are logical build target names. "
"Logical target names must be globally unique because:\n"
" - Unique names may be referenced unambiguously both in CMake\n"
" code and on make tool command lines.\n"
" - Logical names are used by Xcode and VS IDE generators\n"
" to produce meaningful project names for the targets.\n"
"The logical name of executable and library targets does not "
"have to correspond to the physical file names built. "
"Consider using the OUTPUT_NAME target property to create two "
"targets with the same physical name while keeping logical "
"names distinct. "
"Custom targets must simply have globally unique names (unless one "
"uses the global property ALLOW_DUPLICATE_CUSTOM_TARGETS with a "
"Makefiles generator).",
2,6,0, cmPolicies::WARN
);
this->DefinePolicy(
CMP0003, "CMP0003",
"Libraries linked via full path no longer produce linker search paths.",
"This policy affects how libraries whose full paths are NOT known "
"are found at link time, but was created due to a change in how CMake "
"deals with libraries whose full paths are known. "
"Consider the code\n"
" target_link_libraries(myexe /path/to/libA.so)\n"
"CMake 2.4 and below implemented linking to libraries whose full paths "
"are known by splitting them on the link line into separate components "
"consisting of the linker search path and the library name. "
"The example code might have produced something like\n"
" ... -L/path/to -lA ...\n"
"in order to link to library A. "
"An analysis was performed to order multiple link directories such that "
"the linker would find library A in the desired location, but there "
"are cases in which this does not work. "
"CMake versions 2.6 and above use the more reliable approach of passing "
"the full path to libraries directly to the linker in most cases. "
"The example code now produces something like\n"
" ... /path/to/libA.so ....\n"
"Unfortunately this change can break code like\n"
" target_link_libraries(myexe /path/to/libA.so B)\n"
"where \"B\" is meant to find \"/path/to/libB.so\". "
"This code is wrong because the user is asking the linker to find "
"library B but has not provided a linker search path (which may be "
"added with the link_directories command). "
"However, with the old linking implementation the code would work "
"accidentally because the linker search path added for library A "
"allowed library B to be found."
"\n"
"In order to support projects depending on linker search paths "
"added by linking to libraries with known full paths, the OLD "
"behavior for this policy will add the linker search paths even "
"though they are not needed for their own libraries. "
"When this policy is set to OLD, CMake will produce a link line such as\n"
" ... -L/path/to /path/to/libA.so -lB ...\n"
"which will allow library B to be found as it was previously. "
"When this policy is set to NEW, CMake will produce a link line such as\n"
" ... /path/to/libA.so -lB ...\n"
"which more accurately matches what the project specified."
"\n"
"The setting for this policy used when generating the link line is that "
"in effect when the target is created by an add_executable or "
"add_library command. For the example described above, the code\n"
" cmake_policy(SET CMP0003 OLD) # or cmake_policy(VERSION 2.4)\n"
" add_executable(myexe myexe.c)\n"
" target_link_libraries(myexe /path/to/libA.so B)\n"
"will work and suppress the warning for this policy. "
"It may also be updated to work with the corrected linking approach:\n"
" cmake_policy(SET CMP0003 NEW) # or cmake_policy(VERSION 2.6)\n"
" link_directories(/path/to) # needed to find library B\n"
" add_executable(myexe myexe.c)\n"
" target_link_libraries(myexe /path/to/libA.so B)\n"
"Even better, library B may be specified with a full path:\n"
" add_executable(myexe myexe.c)\n"
" target_link_libraries(myexe /path/to/libA.so /path/to/libB.so)\n"
"When all items on the link line have known paths CMake does not check "
"this policy so it has no effect.\n"
"Note that the warning for this policy will be issued for at most "
"one target. This avoids flooding users with messages for every "
"target when setting the policy once will probably fix all targets.",
2,6,0, cmPolicies::WARN);
this->DefinePolicy(
CMP0004, "CMP0004",
"Libraries linked may not have leading or trailing whitespace.",
"CMake versions 2.4 and below silently removed leading and trailing "
"whitespace from libraries linked with code like\n"
" target_link_libraries(myexe \" A \")\n"
"This could lead to subtle errors in user projects.\n"
"The OLD behavior for this policy is to silently remove leading and "
"trailing whitespace. "
"The NEW behavior for this policy is to diagnose the existence of "
"such whitespace as an error. "
"The setting for this policy used when checking the library names is "
"that in effect when the target is created by an add_executable or "
"add_library command.",
2,6,0, cmPolicies::WARN);
this->DefinePolicy(
CMP0005, "CMP0005",
"Preprocessor definition values are now escaped automatically.",
"This policy determines whether or not CMake should generate escaped "
"preprocessor definition values added via add_definitions. "
"CMake versions 2.4 and below assumed that only trivial values would "
"be given for macros in add_definitions calls. "
"It did not attempt to escape non-trivial values such as string "
"literals in generated build rules. "
"CMake versions 2.6 and above support escaping of most values, but "
"cannot assume the user has not added escapes already in an attempt to "
"work around limitations in earlier versions.\n"
"The OLD behavior for this policy is to place definition values given "
"to add_definitions directly in the generated build rules without "
"attempting to escape anything. "
"The NEW behavior for this policy is to generate correct escapes "
"for all native build tools automatically. "
"See documentation of the COMPILE_DEFINITIONS target property for "
"limitations of the escaping implementation.",
2,6,0, cmPolicies::WARN);
this->DefinePolicy(
CMP0006, "CMP0006",
"Installing MACOSX_BUNDLE targets requires a BUNDLE DESTINATION.",
"This policy determines whether the install(TARGETS) command must be "
"given a BUNDLE DESTINATION when asked to install a target with the "
"MACOSX_BUNDLE property set. "
"CMake 2.4 and below did not distinguish application bundles from "
"normal executables when installing targets. "
"CMake 2.6 provides a BUNDLE option to the install(TARGETS) command "
"that specifies rules specific to application bundles on the Mac. "
"Projects should use this option when installing a target with the "
"MACOSX_BUNDLE property set.\n"
"The OLD behavior for this policy is to fall back to the RUNTIME "
"DESTINATION if a BUNDLE DESTINATION is not given. "
"The NEW behavior for this policy is to produce an error if a bundle "
"target is installed without a BUNDLE DESTINATION.",
2,6,0, cmPolicies::WARN);
this->DefinePolicy(
CMP0007, "CMP0007",
"list command no longer ignores empty elements.",
"This policy determines whether the list command will "
"ignore empty elements in the list. "
"CMake 2.4 and below list commands ignored all empty elements"
" in the list. For example, a;b;;c would have length 3 and not 4. "
"The OLD behavior for this policy is to ignore empty list elements. "
"The NEW behavior for this policy is to correctly count empty "
"elements in a list. ",
2,6,0, cmPolicies::WARN);
this->DefinePolicy(
CMP0008, "CMP0008",
"Libraries linked by full-path must have a valid library file name.",
"In CMake 2.4 and below it is possible to write code like\n"
" target_link_libraries(myexe /full/path/to/somelib)\n"
"where \"somelib\" is supposed to be a valid library file name "
"such as \"libsomelib.a\" or \"somelib.lib\". "
"For Makefile generators this produces an error at build time "
"because the dependency on the full path cannot be found. "
"For VS IDE and Xcode generators this used to work by accident because "
"CMake would always split off the library directory and ask the "
"linker to search for the library by name (-lsomelib or somelib.lib). "
"Despite the failure with Makefiles, some projects have code like this "
"and build only with VS and/or Xcode. "
"This version of CMake prefers to pass the full path directly to the "
"native build tool, which will fail in this case because it does "
"not name a valid library file."
"\n"
"This policy determines what to do with full paths that do not appear "
"to name a valid library file. "
"The OLD behavior for this policy is to split the library name from the "
"path and ask the linker to search for it. "
"The NEW behavior for this policy is to trust the given path and "
"pass it directly to the native build tool unchanged.",
2,6,1, cmPolicies::WARN);
this->DefinePolicy(
CMP0009, "CMP0009",
"FILE GLOB_RECURSE calls should not follow symlinks by default.",
"In CMake 2.6.1 and below, FILE GLOB_RECURSE calls would follow "
"through symlinks, sometimes coming up with unexpectedly large "
"result sets because of symlinks to top level directories that "
"contain hundreds of thousands of files."
"\n"
"This policy determines whether or not to follow symlinks "
"encountered during a FILE GLOB_RECURSE call. "
"The OLD behavior for this policy is to follow the symlinks. "
"The NEW behavior for this policy is not to follow the symlinks "
"by default, but only if FOLLOW_SYMLINKS is given as an additional "
"argument to the FILE command.",
2,6,2, cmPolicies::WARN);
this->DefinePolicy(
CMP0010, "CMP0010",
"Bad variable reference syntax is an error.",
"In CMake 2.6.2 and below, incorrect variable reference syntax such as "
"a missing close-brace (\"${FOO\") was reported but did not stop "
"processing of CMake code. "
"This policy determines whether a bad variable reference is an error. "
"The OLD behavior for this policy is to warn about the error, leave "
"the string untouched, and continue. "
"The NEW behavior for this policy is to report an error.",
2,6,3, cmPolicies::WARN);
this->DefinePolicy(
CMP0011, "CMP0011",
"Included scripts do automatic cmake_policy PUSH and POP.",
"In CMake 2.6.2 and below, CMake Policy settings in scripts loaded by "
"the include() and find_package() commands would affect the includer. "
"Explicit invocations of cmake_policy(PUSH) and cmake_policy(POP) were "
"required to isolate policy changes and protect the includer. "
"While some scripts intend to affect the policies of their includer, "
"most do not. "
"In CMake 2.6.3 and above, include() and find_package() by default PUSH "
"and POP an entry on the policy stack around an included script, "
"but provide a NO_POLICY_SCOPE option to disable it. "
"This policy determines whether or not to imply NO_POLICY_SCOPE for "
"compatibility. "
"The OLD behavior for this policy is to imply NO_POLICY_SCOPE for "
"include() and find_package() commands. "
"The NEW behavior for this policy is to allow the commands to do their "
"default cmake_policy PUSH and POP.",
2,6,3, cmPolicies::WARN);
}
cmPolicies::~cmPolicies()
{
// free the policies
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator i
= this->Policies.begin();
for (;i != this->Policies.end(); ++i)
{
delete i->second;
}
}
void cmPolicies::DefinePolicy(cmPolicies::PolicyID iD,
const char *idString,
const char *shortDescription,
const char *longDescription,
unsigned int majorVersionIntroduced,
unsigned int minorVersionIntroduced,
unsigned int patchVersionIntroduced,
cmPolicies::PolicyStatus status)
{
// a policy must be unique and can only be defined once
if (this->Policies.find(iD) != this->Policies.end())
{
cmSystemTools::Error("Attempt to redefine a CMake policy for policy "
"ID ", this->GetPolicyIDString(iD).c_str());
return;
}
this->Policies[iD] = new cmPolicy(iD, idString,
shortDescription,
longDescription,
majorVersionIntroduced,
minorVersionIntroduced,
patchVersionIntroduced,
status);
this->PolicyStringMap[idString] = iD;
}
//----------------------------------------------------------------------------
bool cmPolicies::ApplyPolicyVersion(cmMakefile *mf,
const char *version)
{
std::string ver = "2.4.0";
if (version && strlen(version) > 0)
{
ver = version;
}
unsigned int majorVer = 2;
unsigned int minorVer = 0;
unsigned int patchVer = 0;
// parse the string
if(sscanf(ver.c_str(), "%u.%u.%u",
&majorVer, &minorVer, &patchVer) < 2)
{
cmOStringStream e;
e << "Invalid policy version value \"" << ver << "\". "
<< "A numeric major.minor[.patch] must be given.";
mf->IssueMessage(cmake::FATAL_ERROR, e.str());
return false;
}
// it is an error if the policy version is less than 2.4
if (majorVer < 2 || majorVer == 2 && minorVer < 4)
{
mf->IssueMessage(cmake::FATAL_ERROR,
"An attempt was made to set the policy version of CMake to something "
"earlier than \"2.4\". "
"In CMake 2.4 and below backwards compatibility was handled with the "
"CMAKE_BACKWARDS_COMPATIBILITY variable. "
"In order to get compatibility features supporting versions earlier "
"than 2.4 set policy CMP0001 to OLD to tell CMake to check the "
"CMAKE_BACKWARDS_COMPATIBILITY variable. "
"One way to do this is to set the policy version to 2.4 exactly."
);
return false;
}
// It is an error if the policy version is greater than the running
// CMake.
if (majorVer > cmVersion::GetMajorVersion() ||
(majorVer == cmVersion::GetMajorVersion() &&
minorVer > cmVersion::GetMinorVersion()) ||
(majorVer == cmVersion::GetMajorVersion() &&
minorVer == cmVersion::GetMinorVersion() &&
patchVer > cmVersion::GetPatchVersion()))
{
cmOStringStream e;
e << "An attempt was made to set the policy version of CMake to \""
<< version << "\" which is greater than this version of CMake. "
<< "This is not allowed because the greater version may have new "
<< "policies not known to this CMake. "
<< "You may need a newer CMake version to build this project.";
mf->IssueMessage(cmake::FATAL_ERROR, e.str());
return false;
}
// now loop over all the policies and set them as appropriate
std::vector<cmPolicies::PolicyID> ancientPolicies;
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator i
= this->Policies.begin();
for (;i != this->Policies.end(); ++i)
{
if (i->second->IsPolicyNewerThan(majorVer,minorVer,patchVer))
{
if(i->second->Status == cmPolicies::REQUIRED_ALWAYS)
{
ancientPolicies.push_back(i->first);
}
else if (!mf->SetPolicy(i->second->ID, cmPolicies::WARN))
{
return false;
}
}
else
{
if (!mf->SetPolicy(i->second->ID, cmPolicies::NEW))
{
return false;
}
}
}
// Make sure the project does not use any ancient policies.
if(!ancientPolicies.empty())
{
this->DiagnoseAncientPolicies(ancientPolicies,
majorVer, minorVer, patchVer, mf);
cmSystemTools::SetFatalErrorOccured();
return false;
}
return true;
}
bool cmPolicies::GetPolicyID(const char *id, cmPolicies::PolicyID &pid)
{
if (!id || strlen(id) < 1)
{
return false;
}
std::map<std::string,cmPolicies::PolicyID>::iterator pos =
this->PolicyStringMap.find(id);
if (pos == this->PolicyStringMap.end())
{
return false;
}
pid = pos->second;
return true;
}
std::string cmPolicies::GetPolicyIDString(cmPolicies::PolicyID pid)
{
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator pos =
this->Policies.find(pid);
if (pos == this->Policies.end())
{
return "";
}
return pos->second->IDString;
}
///! return a warning string for a given policy
std::string cmPolicies::GetPolicyWarning(cmPolicies::PolicyID id)
{
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator pos =
this->Policies.find(id);
if (pos == this->Policies.end())
{
cmSystemTools::Error(
"Request for warning text for undefined policy!");
return "Request for warning text for undefined policy!";
}
cmOStringStream msg;
msg <<
"Policy " << pos->second->IDString << " is not set: "
"" << pos->second->ShortDescription << " "
"Run \"cmake --help-policy " << pos->second->IDString << "\" for "
"policy details. "
"Use the cmake_policy command to set the policy "
"and suppress this warning.";
return msg.str();
}
///! return an error string for when a required policy is unspecified
std::string cmPolicies::GetRequiredPolicyError(cmPolicies::PolicyID id)
{
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator pos =
this->Policies.find(id);
if (pos == this->Policies.end())
{
cmSystemTools::Error(
"Request for error text for undefined policy!");
return "Request for warning text for undefined policy!";
}
cmOStringStream error;
error <<
"Policy " << pos->second->IDString << " is not set to NEW: "
"" << pos->second->ShortDescription << " "
"Run \"cmake --help-policy " << pos->second->IDString << "\" for "
"policy details. "
"CMake now requires this policy to be set to NEW by the project. "
"The policy may be set explicitly using the code\n"
" cmake_policy(SET " << pos->second->IDString << " NEW)\n"
"or by upgrading all policies with the code\n"
" cmake_policy(VERSION " << pos->second->GetVersionString() <<
") # or later\n"
"Run \"cmake --help-command cmake_policy\" for more information.";
return error.str();
}
///! Get the default status for a policy
cmPolicies::PolicyStatus
cmPolicies::GetPolicyStatus(cmPolicies::PolicyID id)
{
// if the policy is not know then what?
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator pos =
this->Policies.find(id);
if (pos == this->Policies.end())
{
// TODO is this right?
return cmPolicies::WARN;
}
return pos->second->Status;
}
void cmPolicies::GetDocumentation(std::vector<cmDocumentationEntry>& v)
{
// now loop over all the policies and set them as appropriate
std::map<cmPolicies::PolicyID,cmPolicy *>::iterator i
= this->Policies.begin();
for (;i != this->Policies.end(); ++i)
{
cmOStringStream full;
full << i->second->LongDescription;
full << "\nThis policy was introduced in CMake version ";
full << i->second->GetVersionString() << ".";
if(i->first != cmPolicies::CMP0000)
{
full << " "
<< "CMake version " << cmVersion::GetMajorVersion()
<< "." << cmVersion::GetMinorVersion() << " ";
// add in some more text here based on status
switch (i->second->Status)
{
case cmPolicies::WARN:
full << "warns when the policy is not set and uses OLD behavior. "
<< "Use the cmake_policy command to set it to OLD or NEW "
<< "explicitly.";
break;
case cmPolicies::OLD:
full << "defaults to the OLD behavior for this policy.";
break;
case cmPolicies::NEW:
full << "defaults to the NEW behavior for this policy.";
break;
case cmPolicies::REQUIRED_IF_USED:
full << "requires the policy to be set to NEW if you use it. "
<< "Use the cmake_policy command to set it to NEW.";
break;
case cmPolicies::REQUIRED_ALWAYS:
full << "requires the policy to be set to NEW. "
<< "Use the cmake_policy command to set it to NEW.";
break;
}
}
cmDocumentationEntry e(i->second->IDString.c_str(),
i->second->ShortDescription.c_str(),
full.str().c_str());
v.push_back(e);
}
}
//----------------------------------------------------------------------------
std::string
cmPolicies::GetRequiredAlwaysPolicyError(cmPolicies::PolicyID id)
{
std::string pid = this->GetPolicyIDString(id);
cmOStringStream e;
e << "Policy " << pid << " may not be set to OLD behavior because this "
<< "version of CMake no longer supports it. "
<< "The policy was introduced in "
<< "CMake version " << this->Policies[id]->GetVersionString()
<< ", and use of NEW behavior is now required."
<< "\n"
<< "Please either update your CMakeLists.txt files to conform to "
<< "the new behavior or use an older version of CMake that still "
<< "supports the old behavior. "
<< "Run cmake --help-policy " << pid << " for more information.";
return e.str();
}
//----------------------------------------------------------------------------
void
cmPolicies::DiagnoseAncientPolicies(std::vector<PolicyID> const& ancient,
unsigned int majorVer,
unsigned int minorVer,
unsigned int patchVer,
cmMakefile* mf)
{
cmOStringStream e;
e << "The project requests behavior compatible with CMake version \""
<< majorVer << "." << minorVer << "." << patchVer
<< "\", which requires OLD the behavior for some policies:\n";
for(std::vector<PolicyID>::const_iterator
i = ancient.begin(); i != ancient.end(); ++i)
{
cmPolicy const* policy = this->Policies[*i];
e << " " << policy->IDString << ": " << policy->ShortDescription << "\n";
}
e << "However, this version of CMake no longer supports the OLD "
<< "behavior for these policies. "
<< "Please either update your CMakeLists.txt files to conform to "
<< "the new behavior or use an older version of CMake that still "
<< "supports the old behavior.";
mf->IssueMessage(cmake::FATAL_ERROR, e.str().c_str());
}