4 files changed, 22 insertions, 5 deletions
diff --git a/custom/extensions/about-render.lua b/custom/extensions/about-render.lua
index 35f30d0..e3747ec 100644
--- a/custom/extensions/about-render.lua
+++ b/custom/extensions/about-render.lua
@@ -10,7 +10,8 @@
 --     about-filter=lua:/usr/local/lib/cgit/filters/about-render.lua
 
 -- Markdown and man pages need lpeg, built for the Lua cgit is linked
--- against. Without it both fall back to escaped plain text.
+-- against. Without it both fall back to escaped plain text, and the error
+-- log says so.
 --
 --     # Debian and Ubuntu
 --     sudo apt install lua-lpeg
@@ -21,6 +22,9 @@
 --     # or with LuaRocks, matched to your Lua version
 --     sudo luarocks --lua-version 5.1 install lpeg
 local has_lpeg, lpeg = pcall(require, "lpeg")
+if not has_lpeg then
+	io.stderr:write("[cgit] Unable to load lpeg, so markdown and man pages show as plain text\n")
+end
 
 
 -- Readmes larger than this are served as escaped plain text rather than
diff --git a/custom/extensions/email-gravatar.lua b/custom/extensions/email-gravatar.lua
index 467deff..c89da79 100644
--- a/custom/extensions/email-gravatar.lua
+++ b/custom/extensions/email-gravatar.lua
@@ -13,7 +13,8 @@
 -- openssl.digest, from <https://github.com/wahern/luaossl>. The reliable
 -- cross-platform install is LuaRocks, matched to the Lua version cgit is built
 -- against, and it needs the OpenSSL development headers present. Without it
--- the filter draws no icons and leaves the names as they are.
+-- the filter draws no icons, leaving the names as they are, and says so in the
+-- error log.
 --
 --     # Debian and Ubuntu
 --     sudo apt install luarocks libssl-dev
@@ -33,6 +34,9 @@
 -- SHA-256, the form Gravatar documents.
 
 local has_digest, digest = pcall(require, "openssl.digest")
+if not has_digest then
+	io.stderr:write("[cgit] Unable to load openssl.digest, so no avatar icons are drawn\n")
+end
 
 
 -- The size is in pixels and serves both as the image asked of the service and
diff --git a/custom/extensions/email-libravatar.lua b/custom/extensions/email-libravatar.lua
index 0a6e10c..79794a7 100644
--- a/custom/extensions/email-libravatar.lua
+++ b/custom/extensions/email-libravatar.lua
@@ -12,7 +12,8 @@
 -- openssl.digest, from <https://github.com/wahern/luaossl>. The reliable
 -- cross-platform install is LuaRocks, matched to the Lua version cgit is built
 -- against, and it needs the OpenSSL development headers present. Without it
--- the filter draws no icons and leaves the names as they are.
+-- the filter draws no icons, leaving the names as they are, and says so in the
+-- error log.
 --
 --     # Debian and Ubuntu
 --     sudo apt install luarocks libssl-dev
@@ -32,6 +33,9 @@
 -- SHA-256, which Libravatar accepts alongside MD5.
 
 local has_digest, digest = pcall(require, "openssl.digest")
+if not has_digest then
+	io.stderr:write("[cgit] Unable to load openssl.digest, so no avatar icons are drawn\n")
+end
 
 
 -- The size is in pixels and serves both as the image asked of the service and
diff --git a/custom/extensions/syntax-highlight.lua b/custom/extensions/syntax-highlight.lua
index 7414b63..2928250 100644
--- a/custom/extensions/syntax-highlight.lua
+++ b/custom/extensions/syntax-highlight.lua
@@ -4,8 +4,8 @@
 -- Scintillua lexers and reach the page wrapped in span elements carrying the
 -- hl- classes that assets/cgit.css styles. Whenever a piece is missing or
 -- will not load, from lpeg down to a single lexer, the filter falls back to
--- plain escaped text instead of failing. It runs on Lua 5.1 through 5.5 and
--- LuaJIT.
+-- plain escaped text instead of failing, and a missing lpeg or Scintillua is
+-- noted in the error log. It runs on Lua 5.1 through 5.5 and LuaJIT.
 --
 --     source-filter=lua:/usr/local/lib/cgit/filters/syntax-highlight.lua
 
@@ -140,6 +140,7 @@ end
 local function load_scintillua()
 	local dir = scintillua_path()
 	if not dir then
+		io.stderr:write("[cgit] Unable to find the Scintillua lexers, so source is shown uncoloured\n")
 		return nil
 	end
 	package.path = dir .. "/?.lua;" .. package.path
@@ -149,6 +150,10 @@ local function load_scintillua()
 	if ok and type(mod) == "table" and type(mod.load) == "function" then
 		return mod
 	end
+	if not ok then
+		local reason = tostring(mod):match("[^\n]*")
+		io.stderr:write("[cgit] Unable to load the Scintillua lexers: " .. reason .. "\n")
+	end
 	return nil
 end
-rw-r--r--	custom/extensions/about-render.lua	6
-rw-r--r--	custom/extensions/email-gravatar.lua	6
-rw-r--r--	custom/extensions/email-libravatar.lua	6
-rw-r--r--	custom/extensions/syntax-highlight.lua	9