Generate FISH_BUILD_VERSION info for cmake builds

Correctly generate FISH_BUILD_VERSION for use in fish_version.h/cpp and
fish.pc to allow `fish --version` and `echo $version` to work again.

Not needing the same convoluted measures used by Makefile builds to
prevent the regeneration of the fish version file when it hasn't
changed.

Purposely created a new `cmake_git_version_gen.sh` file so that the old
`git_version_gen.sh` remains compatible with the existing Makefile build
script. Same reason why `fish.pc.in` was not modified to use a lowercase
variable name to match the CMAKE variable of the same name.

Closes #4626

CMakeLists.txt

@@ -55,16 +55,19 @@ SET(FISH_SRCS
 # Header files are just globbed.
 FILE(GLOB FISH_HEADERS src/*.h)
 
-# Set up the version target.
-# This creates the file FISH-BUILD-VERSION-FILE which is only modified if necessary.
-ADD_CUSTOM_COMMAND(OUTPUT "FISH-BUILD-VERSION-FILE"
-                   DEPENDS CHECK-FISH-BUILD-VERSION-FILE)
+# git_version_gen.sh creates FISH-BUILD-VERSION-FILE if it does not exist, and updates it
+# only if it is out-of-date.
+execute_process(
+    COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/build_tools/cmake_git_version_gen.sh"
+    OUTPUT_VARIABLE FISH_BUILD_VERSION)
 
-ADD_CUSTOM_TARGET("CHECK-FISH-BUILD-VERSION-FILE"
-                  COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/build_tools/git_version_gen.sh)
-
-SET(FBVF "FISH-BUILD-VERSION-FILE")
+message(STATUS "FISH_BUILD_VERSION: ${FISH_BUILD_VERSION}")
+ADD_DEFINITIONS(-DFISH_BUILD_VERSION="${FISH_BUILD_VERSION}")
 
+# Set up fish-build-version.h
+configure_file("${CMAKE_CURRENT_SOURCE_DIR}/src/fish_build_version.h.in"
+    "${CMAKE_CURRENT_BINARY_DIR}/include/fish_build_version.h")
+include_directories(${CMAKE_CURRENT_BINARY_DIR}/include)
 
 # Set up config.h
 INCLUDE(cmake/ConfigureChecks.cmake)
@@ -75,8 +78,8 @@ INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
 
 # Set up standard directories.
 INCLUDE(GNUInstallDirs)
-ADD_DEFINITIONS(-D_UNICODE=1
-                -DFISH_BUILD_VERSION="${FISH_BUILD_VERSION}"
+ADD_DEFINITIONS(-DCMAKE
+                -D_UNICODE=1
                 -DLOCALEDIR="${CMAKE_INSTALL_FULL_LOCALEDIR}"
                 -DPREFIX=L"${CMAKE_INSTALL_PREFIX}"
                 -DDATADIR=L"${CMAKE_INSTALL_FULL_DATADIR}"

build_tools/cmake_git_version_gen.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+# Originally from the git sources (GIT-VERSION-GEN)
+# Presumably (C) Junio C Hamano <junkio@cox.net>
+# Reused under GPL v2.0
+# Modified for fish by David Adam <zanchey@ucc.gu.uwa.edu.au>
+
+# Obtain directory containing this script in POSIX-compatible manner
+# See https://stackoverflow.com/a/43919044/17027 (public domain)
+a="/$0"; a="${a%/*}"; a="${a:-.}"; a="${a#/}/"; BASEDIR=$(cd "$a"; pwd)
+# Find the fish git directory as two levels up from this directory.
+GIT_DIR=$(dirname "$a")
+
+DEF_VER=unknown
+
+# First see if there is a version file (included in release tarballs),
+# then try git-describe, then default.
+if test -f version
+then
+	VN=$(cat version) || VN="$DEF_VER"
+elif ! VN=$(git -C "$GIT_DIR" describe --always --dirty 2>/dev/null); then
+	VN="$DEF_VER"
+fi
+
+echo -n "$VN"

cmake/Install.cmake

@@ -109,11 +109,10 @@ FISH_CREATE_DIRS(${rel_datadir}/pkgconfig ${extra_completionsdir}
 
 # @echo "Installing pkgconfig file"
 # $v $(INSTALL) -m 644 fish.pc $(DESTDIR)$(datadir)/pkgconfig
-CONFIGURE_FILE(fish.pc.in fish.pc.noversion)
-ADD_CUSTOM_COMMAND(OUTPUT fish.pc
-  COMMAND awk -v `cat ${FBVF}` '/^Version:/ {$$0=$$0 FISH_BUILD_VERSION} 1' fish.pc.noversion  > fish.pc
-  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-  DEPENDS ${FBVF} ${CMAKE_CURRENT_BINARY_DIR}/fish.pc.noversion)
+
+# main CMakeFiles.txt sets ${FISH_BUILD_VERSION}, not ${fish_build_version}
+set(fish_build_version ${FISH_BUILD_VERSION})
+CONFIGURE_FILE(fish.pc.in fish.pc)
 
 ADD_CUSTOM_TARGET(build_fish_pc ALL DEPENDS fish.pc)
 
@@ -181,7 +180,7 @@ INSTALL(FILES ${MANUALS} DESTINATION ${mandir}/man1/ OPTIONAL)
 INSTALL(FILES share/lynx.lss DESTINATION ${rel_datadir}/fish/)
 
 # Group install targets into a InstallTargets folder
-SET_PROPERTY(TARGET CHECK-FISH-BUILD-VERSION-FILE build_fish_pc
+SET_PROPERTY(TARGET build_fish_pc
                     test_invocation test_fishscript
                     test_prep tests_buildroot_target
                     build_lexicon_filter

src/fish_build_version.h.in

@@ -0,0 +1,4 @@
+#pragma once
+
+//to be filled in by cmake
+#define FISH_BUILD_VERSION "@FISH_BUILD_VERSION@"

src/fish_version.h

@@ -1,2 +1,5 @@
 // Prototype for version receiver.
+#ifdef CMAKE
+#include <fish_build_version.h>
+#endif
 const char *get_fish_version();