feat: report "build" in vim.version() neovim#23925

Problem:
Nvim version string typically has a "build" component
but vim.version() doesn't report it.

Solution:
Add the "build" field to vim.version().

Closes neovim#23863

cmake/GenerateVersion.cmake

@@ -14,6 +14,9 @@ if(RES)
   return()
 endif()
 
+# Extract build info: "v0.9.0-145-g0f9113907" => "g0f9113907"
+string(REGEX REPLACE ".*\\-" "" NVIM_VERSION_BUILD "${GIT_TAG}")
+
 # `git describe` annotates the most recent tagged release; for pre-release
 # builds we append that to the dev version.
 if(NVIM_VERSION_PRERELEASE)
@@ -24,7 +27,7 @@ if(NVIM_VERSION_PRERELEASE)
   set(NVIM_VERSION "${NVIM_VERSION}-${NVIM_VERSION_GIT}")
 endif()
 
-set(NVIM_VERSION_STRING "#define NVIM_VERSION_MEDIUM \"${NVIM_VERSION}\"\n")
+set(NVIM_VERSION_STRING "#define NVIM_VERSION_MEDIUM \"${NVIM_VERSION}\"\n#define NVIM_VERSION_BUILD \"${NVIM_VERSION_BUILD}\"\n")
 
 string(SHA1 CURRENT_VERSION_HASH "${NVIM_VERSION_STRING}")
 if(EXISTS ${OUTPUT})

src/nvim/version.c

@@ -2560,6 +2560,11 @@ Dictionary version_dict(void)
   PUT(d, "major", INTEGER_OBJ(NVIM_VERSION_MAJOR));
   PUT(d, "minor", INTEGER_OBJ(NVIM_VERSION_MINOR));
   PUT(d, "patch", INTEGER_OBJ(NVIM_VERSION_PATCH));
+#ifndef NVIM_VERSION_BUILD
+  PUT(d, "build", NIL);
+#else
+  PUT(d, "build", CSTR_AS_OBJ(NVIM_VERSION_BUILD));
+#endif
   PUT(d, "prerelease", BOOLEAN_OBJ(NVIM_VERSION_PRERELEASE[0] != '\0'));
   PUT(d, "api_level", INTEGER_OBJ(NVIM_API_LEVEL));
   PUT(d, "api_compatible", INTEGER_OBJ(NVIM_API_LEVEL_COMPAT));

test/functional/api/version_spec.lua

@@ -34,6 +34,7 @@ describe("api_info()['version']", function()
     local minor   = version['minor']
     local patch   = version['patch']
     local prerelease = version['prerelease']
+    local build   = version['build']
     eq("number", type(major))
     eq("number", type(minor))
     eq("number", type(patch))
@@ -42,6 +43,7 @@ describe("api_info()['version']", function()
     eq(0, funcs.has("nvim-"..major.."."..minor.."."..(patch + 1)))
     eq(0, funcs.has("nvim-"..major.."."..(minor + 1).."."..patch))
     eq(0, funcs.has("nvim-"..(major + 1).."."..minor.."."..patch))
+    assert(build == nil or type(build) == 'string')
   end)
 end)