http-parser: use our bundled http-parser by defaultethomson/urlparse_empty_port

Our bundled http-parser includes bugfixes, therefore we should prefer
our http-parser until such time as we can identify that the system
http-parser has these bugfixes (using a version check).

Since these bugs are - at present - minor, retain the ability for users
to force that they want to use the system http-parser anyway.  This does
change the cmake specification so that people _must_ opt-in to the new
behavior knowingly.

3 files changed, 29 insertions, 7 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 007963c10..b7f2bc746 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -60,10 +60,10 @@ OPTION(USE_HTTPS			"Enable HTTPS support. Can be set to a specific backend" ON)
 OPTION(USE_GSSAPI			"Link with libgssapi for SPNEGO auth"			OFF)
 OPTION(USE_STANDALONE_FUZZERS		"Enable standalone fuzzers (compatible with gcc)"	OFF)
 OPTION(VALGRIND				"Configure build for valgrind"				OFF)
-OPTION(USE_EXT_HTTP_PARSER		"Use system HTTP_Parser if available"			 ON)
 OPTION(DEBUG_POOL			"Enable debug pool allocator"				OFF)
 OPTION(ENABLE_WERROR			"Enable compilation with -Werror"			OFF)
 OPTION(USE_BUNDLED_ZLIB    		"Use the bundled version of zlib"			OFF)
+   SET(USE_HTTP_PARSER			"" CACHE STRING "Specifies the HTTP Parser implementation; either system or builtin.")
 OPTION(DEPRECATE_HARD			"Do not include deprecated functions in the library"	OFF)
    SET(REGEX_BACKEND			"" CACHE STRING "Regular expression implementation. One of regcomp_l, pcre2, pcre, regcomp, or builtin.")
 
diff --git a/docs/changelog.md b/docs/changelog.md
index 666eecd17..75f839212 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,3 +1,20 @@
+v0.28 + 1
+---------
+
+### Breaking CMake configuration changes
+
+* The CMake option to use a system http-parser library, instead of the
+  bundled dependency, has changed.  This is due to a deficiency in
+  http-parser that we have fixed in our implementation.  The bundled
+  library is now the default, but if you wish to force the use of the
+  system http-parser implementation despite incompatibilities, you can
+  specify `-DUSE_HTTP_PARSER=system` to CMake.
+
+### Changes or improvements
+
+* libgit2 can now correctly cope with URLs where the host contains a colon
+  but a port is not specified.  (eg `http://example.com:/repo.git`).
+
 v0.28
 -----
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 647bb097a..5a0cf347c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -340,12 +340,17 @@ ELSE()
 ENDIF()
 
 # Optional external dependency: http-parser
-FIND_PACKAGE(HTTP_Parser)
-IF (USE_EXT_HTTP_PARSER AND HTTP_PARSER_FOUND AND HTTP_PARSER_VERSION_MAJOR EQUAL 2)
-	LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${HTTP_PARSER_INCLUDE_DIRS})
-	LIST(APPEND LIBGIT2_LIBS ${HTTP_PARSER_LIBRARIES})
-	LIST(APPEND LIBGIT2_PC_LIBS "-lhttp_parser")
-	ADD_FEATURE_INFO(http-parser ON "http-parser support")
+IF(USE_HTTP_PARSER STREQUAL "system")
+	FIND_PACKAGE(HTTP_Parser)
+
+	IF (HTTP_PARSER_FOUND AND HTTP_PARSER_VERSION_MAJOR EQUAL 2)
+		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${HTTP_PARSER_INCLUDE_DIRS})
+		LIST(APPEND LIBGIT2_LIBS ${HTTP_PARSER_LIBRARIES})
+		LIST(APPEND LIBGIT2_PC_LIBS "-lhttp_parser")
+		ADD_FEATURE_INFO(http-parser ON "http-parser support (system)")
+	ELSE()
+		MESSAGE(FATAL_ERROR "http-parser support was requested but not found")
+	ENDIF()
 ELSE()
 	MESSAGE(STATUS "http-parser version 2 was not found or disabled; using bundled 3rd-party sources.")
 	ADD_SUBDIRECTORY("${libgit2_SOURCE_DIR}/deps/http-parser" "${libgit2_BINARY_DIR}/deps/http-parser")