From 880ca66b51551d5ee732c7b81349c1a5f724d093 Mon Sep 17 00:00:00 2001
From: Alex Turbov <i.zaufi@gmail.com>
Date: Mon, 9 Aug 2021 20:58:27 +0300
Subject: Fix: `while()` can silently ignore incorrect condition

When `conditionEvaluator.IsTrue(...)` returns `false` it just
didn't print the error occured.
---
 Source/cmWhileCommand.cxx                          | 36 +++++++++++-----------
 .../while/unbalanced-parenthesis-result.txt        |  1 +
 .../while/unbalanced-parenthesis-stderr.txt        |  5 +++
 Tests/RunCMake/while/unbalanced-parenthesis.cmake  |  2 +-
 4 files changed, 25 insertions(+), 19 deletions(-)
 create mode 100644 Tests/RunCMake/while/unbalanced-parenthesis-result.txt
 create mode 100644 Tests/RunCMake/while/unbalanced-parenthesis-stderr.txt

diff --git a/Source/cmWhileCommand.cxx b/Source/cmWhileCommand.cxx
index 327c1c7..1363386 100644
--- a/Source/cmWhileCommand.cxx
+++ b/Source/cmWhileCommand.cxx
@@ -75,24 +75,6 @@ bool cmWhileFunctionBlocker::Replay(std::vector<cmListFileFunction> functions,
     conditionEvaluator.IsTrue(expandedArguments, errorString, messageType);
 
   while (isTrue) {
-    if (!errorString.empty()) {
-      std::string err = "had incorrect arguments: ";
-      for (cmListFileArgument const& arg : this->Args) {
-        err += (arg.Delim ? "\"" : "");
-        err += arg.Value;
-        err += (arg.Delim ? "\"" : "");
-        err += " ";
-      }
-      err += "(";
-      err += errorString;
-      err += ").";
-      mf.GetCMakeInstance()->IssueMessage(messageType, err, whileBT);
-      if (messageType == MessageType::FATAL_ERROR) {
-        cmSystemTools::SetFatalErrorOccured();
-        return true;
-      }
-    }
-
     // Invoke all the functions that were collected in the block.
     for (cmListFileFunction const& fn : functions) {
       cmExecutionStatus status(mf);
@@ -116,6 +98,24 @@ bool cmWhileFunctionBlocker::Replay(std::vector<cmListFileFunction> functions,
     isTrue =
       conditionEvaluator.IsTrue(expandedArguments, errorString, messageType);
   }
+
+  if (!isTrue && !errorString.empty()) {
+    std::string err = "had incorrect arguments: ";
+    for (cmListFileArgument const& arg : this->Args) {
+      err += (arg.Delim ? "\"" : "");
+      err += arg.Value;
+      err += (arg.Delim ? "\"" : "");
+      err += " ";
+    }
+    err += "(";
+    err += errorString;
+    err += ").";
+    mf.GetCMakeInstance()->IssueMessage(messageType, err, whileBT);
+    if (messageType == MessageType::FATAL_ERROR) {
+      cmSystemTools::SetFatalErrorOccured();
+    }
+  }
+
   return true;
 }
 
diff --git a/Tests/RunCMake/while/unbalanced-parenthesis-result.txt b/Tests/RunCMake/while/unbalanced-parenthesis-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/while/unbalanced-parenthesis-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/while/unbalanced-parenthesis-stderr.txt b/Tests/RunCMake/while/unbalanced-parenthesis-stderr.txt
new file mode 100644
index 0000000..33ac54a
--- /dev/null
+++ b/Tests/RunCMake/while/unbalanced-parenthesis-stderr.txt
@@ -0,0 +1,5 @@
+CMake Error at unbalanced-parenthesis.cmake:[0-9]+ \(while\):
+  had incorrect arguments: NOT \$\{var_with_paren\} IN_LIST some_list
+  \(mismatched parenthesis in condition\).
+Call Stack \(most recent call first\):
+  CMakeLists\.txt:[0-9]+ \(include\)
diff --git a/Tests/RunCMake/while/unbalanced-parenthesis.cmake b/Tests/RunCMake/while/unbalanced-parenthesis.cmake
index 4b6a5cd..7a12701 100644
--- a/Tests/RunCMake/while/unbalanced-parenthesis.cmake
+++ b/Tests/RunCMake/while/unbalanced-parenthesis.cmake
@@ -5,4 +5,4 @@ while(NOT ${var_with_paren} IN_LIST some_list)
   message(STATUS "Never prints")
 endwhile()
 
-message(STATUS "It prints but in fact `while()` have to fail")
+message(STATUS "Never prints")
-- 
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