[vcpkg] Harden file removals and clean directory contents in "CI" inside vcpkg itself. (#11432)

`files.h/files.cpp`:
* Add end and else comments to all macros.
* Add "remove_all_inside" function which empties a directory without actually deleting the directory. This is necessary to handle the case where the directory is actually a directory symlink.
* Change remove_all to use std::remove when VCPKG_USE_STD_FILESYSTEM is set; this will engage POSIX delete support available on current Win10.

`commands.ci.cpp`: empty "installed".

`*/initialize_environment.*`: No longer clean the directories outside the tool.

`ci-step.ps1`: Remove unused console output tee-ing.

2 files changed, 118 insertions, 27 deletions

diff --git a/toolsrc/src/vcpkg/base/files.cpp b/toolsrc/src/vcpkg/base/files.cpp
index 2d12b1757..24e2038d9 100644
--- a/toolsrc/src/vcpkg/base/files.cpp
+++ b/toolsrc/src/vcpkg/base/files.cpp
@@ -13,12 +13,12 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
-#endif
+#endif // ^^^ !defined(_WIN32)
 #if defined(__linux__)
 #include <sys/sendfile.h>
 #elif defined(__APPLE__)
 #include <copyfile.h>
-#endif
+#endif // ^^^ defined(__APPLE__)
 
 namespace vcpkg::Files
 {
@@ -80,7 +80,7 @@ namespace vcpkg::Files
 
             return fs::file_status(ft, permissions);
 
-#else
+#else // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
             auto result = follow_symlinks ? fs::stdfs::status(p, ec) : fs::stdfs::symlink_status(p, ec);
             // libstdc++ doesn't correctly not-set ec on nonexistent paths
             if (ec.value() == ENOENT || ec.value() == ENOTDIR)
@@ -89,7 +89,7 @@ namespace vcpkg::Files
                 return fs::file_status(file_type::not_found, perms::unknown);
             }
             return fs::file_status(result.type(), result.permissions());
-#endif
+#endif// ^^^ !defined(_WIN32)
         }
 
         fs::file_status status(const fs::path& p, std::error_code& ec) noexcept
@@ -119,7 +119,7 @@ namespace vcpkg::Files
             {
                 ec.assign(GetLastError(), std::system_category());
             }
-#else
+#else  // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
             struct stat s;
             if (lstat(path.c_str(), &s))
             {
@@ -137,7 +137,7 @@ namespace vcpkg::Files
                     ec.assign(errno, std::system_category());
                 }
             }
-#endif
+#endif // ^^^ !defined(_WIN32)
         }
     }
 
@@ -272,6 +272,31 @@ namespace vcpkg::Files
         this->remove_all(path, ec, failure_point);
     }
 
+    void Filesystem::remove_all_inside(const fs::path& path, LineInfo li)
+    {
+        std::error_code ec;
+        fs::path failure_point;
+
+        this->remove_all_inside(path, ec, failure_point);
+
+        if (ec)
+        {
+            Checks::exit_with_message(li,
+                                      "Failure to remove_all_inside(%s) due to file %s: %s",
+                                      path.string(),
+                                      failure_point.string(),
+                                      ec.message());
+        }
+    }
+
+    void Filesystem::remove_all_inside(const fs::path& path, ignore_errors_t)
+    {
+        std::error_code ec;
+        fs::path failure_point;
+
+        this->remove_all_inside(path, ec, failure_point);
+    }
+
     fs::path Filesystem::absolute(LineInfo li, const fs::path& path) const
     {
         std::error_code ec;
@@ -477,7 +502,7 @@ namespace vcpkg::Files
                 auto written_bytes = sendfile(o_fd, i_fd, &bytes, info.st_size);
 #elif defined(__APPLE__)
                 auto written_bytes = fcopyfile(i_fd, o_fd, 0, COPYFILE_ALL);
-#else
+#else // ^^^ defined(__APPLE__) // !(defined(__APPLE__) || defined(__linux__)) vvv
                 ssize_t written_bytes = 0;
                 {
                     constexpr std::size_t buffer_length = 4096;
@@ -505,7 +530,7 @@ namespace vcpkg::Files
 
                 copy_failure:;
                 }
-#endif
+#endif // ^^^ !(defined(__APPLE__) || defined(__linux__))
                 if (written_bytes == -1)
                 {
                     ec.assign(errno, std::generic_category());
@@ -522,7 +547,7 @@ namespace vcpkg::Files
                 if (ec) return;
                 this->remove(oldpath, ec);
             }
-#endif
+#endif // ^^^ !defined(_WIN32)
         }
         virtual bool remove(const fs::path& path, std::error_code& ec) override { return fs::stdfs::remove(path, ec); }
         virtual void remove_all(const fs::path& path, std::error_code& ec, fs::path& failure_point) override
@@ -574,13 +599,20 @@ namespace vcpkg::Files
                         {
                             ec.assign(GetLastError(), std::system_category());
                         }
-#else
+#else // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
                         if (rmdir(current_path.c_str()))
                         {
                             ec.assign(errno, std::system_category());
                         }
-#endif
+#endif // ^^^ !defined(_WIN32)
                     }
+#if VCPKG_USE_STD_FILESYSTEM
+                    else
+                    {
+                        fs::stdfs::remove(current_path, ec);
+                        if (check_ec(ec, current_path, err)) return;
+                    }
+#else // ^^^ VCPKG_USE_STD_FILESYSTEM // !VCPKG_USE_STD_FILESYSTEM vvv
 #if defined(_WIN32)
                     else if (path_type == fs::file_type::directory_symlink)
                     {
@@ -596,7 +628,7 @@ namespace vcpkg::Files
                             ec.assign(GetLastError(), std::system_category());
                         }
                     }
-#else
+#else // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
                     else
                     {
                         if (unlink(current_path.c_str()))
@@ -604,7 +636,8 @@ namespace vcpkg::Files
                             ec.assign(errno, std::system_category());
                         }
                     }
-#endif
+#endif // ^^^ !defined(_WIN32)
+#endif // ^^^ !VCPKG_USE_STD_FILESYSTEM
 
                     check_ec(ec, current_path, err);
                 }
@@ -651,6 +684,58 @@ namespace vcpkg::Files
             ec = std::move(err.ec);
             failure_point = std::move(err.failure_point);
         }
+
+        virtual void remove_all_inside(const fs::path& path, std::error_code& ec, fs::path& failure_point) override
+        {
+            fs::directory_iterator last{};
+            fs::directory_iterator first(path, ec);
+            if (ec)
+            {
+                failure_point = path;
+                return;
+            }
+
+            for (;;)
+            {
+                if (first == last)
+                {
+                    return;
+                }
+
+                auto stats = first->status(ec);
+                if (ec)
+                {
+                    break;
+                }
+
+                auto& thisPath = first->path();
+                if (stats.type() == fs::stdfs::file_type::directory)
+                {
+                    this->remove_all(thisPath, ec, failure_point);
+                    if (ec)
+                    {
+                        return; // keep inner failure_point
+                    }
+                }
+                else
+                {
+                    this->remove(thisPath, ec);
+                    if (ec)
+                    {
+                        break;
+                    }
+                }
+
+                first.increment(ec);
+                if (ec)
+                {
+                    break;
+                }
+            }
+
+            failure_point = first->path();
+        }
+
         virtual bool is_directory(const fs::path& path) const override { return fs::stdfs::is_directory(path); }
         virtual bool is_regular_file(const fs::path& path) const override { return fs::stdfs::is_regular_file(path); }
         virtual bool is_empty(const fs::path& path) const override { return fs::stdfs::is_empty(path); }
@@ -693,10 +778,10 @@ namespace vcpkg::Files
             FILE* f = nullptr;
 #if defined(_WIN32)
             auto err = _wfopen_s(&f, file_path.native().c_str(), L"wb");
-#else
+#else // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
             f = fopen(file_path.native().c_str(), "wb");
             int err = f != nullptr ? 0 : 1;
-#endif
+#endif // ^^^ !defined(_WIN32)
             if (err != 0)
             {
                 ec.assign(err, std::system_category());
@@ -720,19 +805,22 @@ namespace vcpkg::Files
 #if VCPKG_USE_STD_FILESYSTEM
             return fs::stdfs::absolute(path, ec);
 #else // ^^^ VCPKG_USE_STD_FILESYSTEM  / !VCPKG_USE_STD_FILESYSTEM  vvv
-#if _WIN32
+#if defined(_WIN32)
             // absolute was called system_complete in experimental filesystem
             return fs::stdfs::system_complete(path, ec);
-#else // ^^^ _WIN32 / !_WIN32 vvv
-            if (path.is_absolute()) {
+#else // ^^^ defined(_WIN32) / !defined(_WIN32) vvv
+            if (path.is_absolute())
+            {
                 return path;
-            } else {
+            }
+            else
+            {
                 auto current_path = this->current_path(ec);
                 if (ec) return fs::path();
                 return std::move(current_path) / path;
             }
-#endif
-#endif
+#endif // ^^^ !defined(_WIN32)
+#endif // ^^^ !VCPKG_USE_STD_FILESYSTEM
         }
 
         virtual fs::path canonical(const fs::path& path, std::error_code& ec) const override
@@ -740,20 +828,17 @@ namespace vcpkg::Files
             return fs::stdfs::canonical(path, ec);
         }
 
-        virtual fs::path current_path(std::error_code& ec) const override
-        {
-            return fs::stdfs::current_path(ec);
-        }
+        virtual fs::path current_path(std::error_code& ec) const override { return fs::stdfs::current_path(ec); }
 
         virtual std::vector<fs::path> find_from_PATH(const std::string& name) const override
         {
 #if defined(_WIN32)
             static constexpr StringLiteral EXTS[] = {".cmd", ".exe", ".bat"};
             auto paths = Strings::split(System::get_environment_variable("PATH").value_or_exit(VCPKG_LINE_INFO), ";");
-#else
+#else // ^^^ defined(_WIN32) // !defined(_WIN32) vvv
             static constexpr StringLiteral EXTS[] = {""};
             auto paths = Strings::split(System::get_environment_variable("PATH").value_or_exit(VCPKG_LINE_INFO), ":");
-#endif
+#endif // ^^^ !defined(_WIN32)
 
             std::vector<fs::path> ret;
             std::error_code ec;
diff --git a/toolsrc/src/vcpkg/commands.ci.cpp b/toolsrc/src/vcpkg/commands.ci.cpp
index 0ea23cd82..eadfd8bdd 100644
--- a/toolsrc/src/vcpkg/commands.ci.cpp
+++ b/toolsrc/src/vcpkg/commands.ci.cpp
@@ -397,6 +397,12 @@ namespace vcpkg::Commands::CI
 
         const ParsedArguments options = args.parse_arguments(COMMAND_STRUCTURE);
 
+        auto& filesystem = paths.get_filesystem();
+        if (filesystem.is_directory(paths.installed))
+        {
+            filesystem.remove_all_inside(paths.installed, VCPKG_LINE_INFO);
+        }
+
         std::set<std::string> exclusions_set;
         auto it_exclusions = options.settings.find(OPTION_EXCLUDE);
         if (it_exclusions != options.settings.end())