Avoid unnecessary Docs.META initializations

If the target module does not have a Docs.META dict (e.g. if
`--strip-metadata` is used), `Docs.meta()` has the side effect of
creating a new IdDict and initializing the Docs.META field of the target
module.

We need to avoid eval'ing into modules after they've been closed, so for
methods that do not mutate the new IdDict we should avoid the init.

Resolves #48390.

Co-authored-by: Steve Kelly <kd2cca@gmail.com>

Author: topolarity

base/docs/Docs.jl

@@ -161,11 +161,13 @@ end
 function docstr(binding::Binding, typesig = Union{})
     @nospecialize typesig
     for m in modules
-        dict = meta(m)
-        if haskey(dict, binding)
-            docs = dict[binding].docs
-            if haskey(docs, typesig)
-                return docs[typesig]
+        if isdefined(m, META) && getfield(m, META) !== nothing
+            dict = meta(m)
+            if haskey(dict, binding)
+                docs = dict[binding].docs
+                if haskey(docs, typesig)
+                    return docs[typesig]
+                end
             end
         end
     end

stdlib/REPL/src/docview.jl

@@ -164,12 +164,14 @@ function doc(binding::Binding, sig::Type = Union{})
     results, groups = DocStr[], MultiDoc[]
     # Lookup `binding` and `sig` for matches in all modules of the docsystem.
     for mod in modules
-        dict = meta(mod)
-        if haskey(dict, binding)
-            multidoc = dict[binding]
-            push!(groups, multidoc)
-            for msig in multidoc.order
-                sig <: msig && push!(results, multidoc.docs[msig])
+        if isdefined(mod, Docs.META) && getfield(mod, Docs.META) !== nothing
+            dict = meta(mod)
+            if haskey(dict, binding)
+                multidoc = dict[binding]
+                push!(groups, multidoc)
+                for msig in multidoc.order
+                    sig <: msig && push!(results, multidoc.docs[msig])
+                end
             end
         end
     end
@@ -565,14 +567,16 @@ Return documentation for a particular `field` of a type if it exists.
 """
 function fielddoc(binding::Binding, field::Symbol)
     for mod in modules
-        dict = meta(mod)
-        if haskey(dict, binding)
-            multidoc = dict[binding]
-            if haskey(multidoc.docs, Union{})
-                fields = multidoc.docs[Union{}].data[:fields]
-                if haskey(fields, field)
-                    doc = fields[field]
-                    return isa(doc, Markdown.MD) ? doc : Markdown.parse(doc)
+        if isdefined(mod, Docs.META) && getfield(mod, Docs.META) !== nothing
+            dict = meta(mod)
+            if haskey(dict, binding)
+                multidoc = dict[binding]
+                if haskey(multidoc.docs, Union{})
+                    fields = multidoc.docs[Union{}].data[:fields]
+                    if haskey(fields, field)
+                        doc = fields[field]
+                        return isa(doc, Markdown.MD) ? doc : Markdown.parse(doc)
+                    end
                 end
             end
         end
@@ -834,8 +838,10 @@ function apropos(io::IO, needle::Regex)
     for mod in modules
         # Module doc might be in README.md instead of the META dict
         docsearch(doc(mod), needle) && println(io, mod)
-        for (k, v) in meta(mod)
-            docsearch(v, needle) && println(io, k)
+        if isdefined(mod, Docs.META) && getfield(mod, Docs.META) !== nothing
+            for (k, v) in meta(mod)
+                docsearch(v, needle) && println(io, k)
+            end
         end
     end
 end