Make `luarocks doc` return something meaningful even for rocks that are not installed.

1 files changed, 34 insertions, 10 deletions

diff --git a/src/luarocks/doc.lua b/src/luarocks/doc.lua
index 1a843f37..324bf028 100644
--- a/src/luarocks/doc.lua
+++ b/src/luarocks/doc.lua
@@ -9,6 +9,7 @@ local path = require("luarocks.path")
 local dir = require("luarocks.dir")
 local fetch = require("luarocks.fetch")
 local fs = require("luarocks.fs")
+local download = require("luarocks.download")
 
 help_summary = "Shows documentation for an installed rock."
 
@@ -24,6 +25,33 @@ With these flags, return only the desired information:
 For more information about a rock, see the 'show' command.
 ]]
 
+local function show_homepage(homepage, name, version)
+   if not homepage then
+      return nil, "No 'homepage' field in rockspec for "..name.." "..version
+   end
+   util.printout("Opening "..homepage.." ...")
+   fs.browser(homepage)
+   return true
+end
+
+local function try_to_open_homepage(name, version)
+   local temp_dir, err = fs.make_temp_dir("doc-"..name.."-"..(version or ""))
+   if not temp_dir then
+      return nil, "Failed creating temporary directory: "..err
+   end
+   util.schedule_function(fs.delete, temp_dir)
+   local ok, err = fs.change_dir(temp_dir)
+   if not ok then return nil, err end
+   local filename, err = download.download("rockspec", name, version)
+   if not filename then return nil, err end
+   local rockspec, err = fetch.load_local_rockspec(filename)
+   if not rockspec then return nil, err end
+   fs.pop_dir()
+   local descript = rockspec.description or {}
+   if not descript.homepage then return nil, "No homepage defined for "..name end
+   return show_homepage(descript.homepage, name, version)
+end
+
 --- Driver function for "doc" command.
 -- @param name or nil: an existing package name.
 -- @param version string or nil: a version may also be passed.
@@ -34,23 +62,19 @@ function run(...)
       return nil, "Argument missing. "..util.see_help("doc")
    end
 
-   local repo
-   name, version, repo = show.pick_installed_rock(name, version, flags["tree"])
-   if not name then
-      return nil, version
+   local iname, iversion, repo = show.pick_installed_rock(name, version, flags["tree"])
+   if not iname then
+      util.printout(name..(version and " "..version or "").." is not installed. Looking for it in the rocks servers...")
+      return try_to_open_homepage(name, version)
    end
+   name, version = iname, iversion
    
    local rockspec, err = fetch.load_local_rockspec(path.rockspec_file(name, version, repo))
    if not rockspec then return nil,err end
    local descript = rockspec.description or {}
 
    if flags["homepage"] then
-      if not descript.homepage then
-         return nil, "No 'homepage' field in rockspec for "..name.." "..version
-      end
-      util.printout("Opening "..descript.homepage.." ...")
-      fs.browser(descript.homepage)
-      return true
+      return show_homepage(descript.homepage, name, version)
    end
 
    local directory = path.install_dir(name,version,repo)