From 2328358a8bf210e840a59209eeee238658daf6f3 Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Sat, 6 Jan 2024 04:11:40 -0600
Subject: [PATCH] Eval thunks that create methods

Fixes #792
---
 src/lowered.jl    | 19 +++++++++++++++++--
 test/backedges.jl |  2 +-
 test/runtests.jl  | 22 +++++++++++++++++++++-
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/src/lowered.jl b/src/lowered.jl
index fdf6ba35..d47fa7f9 100644
--- a/src/lowered.jl
+++ b/src/lowered.jl
@@ -54,13 +54,25 @@ function categorize_stmt(@nospecialize(stmt))
     ismeth, haseval, isinclude, isnamespace, istoplevel = false, false, false, false, false
     if isa(stmt, Expr)
         haseval = matches_eval(stmt)
-        ismeth = stmt.head === :method
+        ismeth = stmt.head === :method || (stmt.head === :thunk && defines_function(only(stmt.args)))
         istoplevel = stmt.head === :toplevel
         isnamespace = stmt.head === :export || stmt.head === :import || stmt.head === :using
         isinclude = stmt.head === :call && stmt.args[1] === :include
     end
     return ismeth, haseval, isinclude, isnamespace, istoplevel
 end
+# Check for thunks that define functions (fixes #792)
+function defines_function(ci)
+    isa(ci, CodeInfo) || return false
+    if length(ci.code) == 1
+        stmt = ci.code[1]
+        if isa(stmt, Core.ReturnNode)
+            val = stmt.val
+            isexpr(val, :method) && return true
+        end
+    end
+    return false
+end
 
 """
     isrequired, evalassign = minimal_evaluation!([predicate,] methodinfo, src::Core.CodeInfo, mode::Symbol)
@@ -280,6 +292,9 @@ function methods_by_execution!(@nospecialize(recurse), methodinfo, docexprs, fra
                 end
                 isassign(frame, pc) && assign_this!(frame, value)
                 pc = next_or_nothing!(frame)
+            elseif head === :thunk && defines_function(only(stmt.args))
+                mode !== :sigs && Core.eval(mod, stmt)
+                pc = next_or_nothing!(frame)
             # elseif head === :thunk && isanonymous_typedef(stmt.args[1])
             #     # Anonymous functions should just be defined anew, since there does not seem to be a practical
             #     # way to find them within the already-defined module.
@@ -300,7 +315,7 @@ function methods_by_execution!(@nospecialize(recurse), methodinfo, docexprs, fra
                             add_signature!(methodinfo, sig, lnn)
                         end
                     end
-                    pc += 1
+                    pc = next_or_nothing!(frame)
                 else
                     pc, pc3 = ret
                     # Get the line number from the body
diff --git a/test/backedges.jl b/test/backedges.jl
index 9af7397c..440adaf6 100644
--- a/test/backedges.jl
+++ b/test/backedges.jl
@@ -17,7 +17,7 @@ do_test("Backedges") && @testset "Backedges" begin
     src2 = src.code[idtype].args[1]
     methodinfo = Revise.MethodInfo()
     isrequired = Revise.minimal_evaluation!(methodinfo, frame, :sigs)[1]
-    @test sum(isrequired) == length(src.code)-2  # skips the `return` at the end
+    @test sum(isrequired) == length(src.code)-1  # skips the `return` at the end
 
     src = """
     # issue #249
diff --git a/test/runtests.jl b/test/runtests.jl
index 7b83352e..3f743209 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -15,7 +15,7 @@ using Base.CoreLogging: Debug,Info
 using Revise.CodeTracking: line_is_decl
 
 # In addition to using this for the "More arg-modifying macros" test below,
-# this package is used on Travis to test what happens when you have multiple
+# this package is used on CI to test what happens when you have multiple
 # *.ji files for the package.
 using EponymTuples
 
@@ -41,6 +41,12 @@ macro addint(ex)
     :($(esc(ex))::$(esc(Int)))
 end
 
+macro empty_function(name)
+    return esc(quote
+        function $name end
+    end)
+end
+
 # The following two submodules are for testing #199
 module A
 f(x::Int) = 1
@@ -1409,6 +1415,20 @@ const issue639report = []
         @test MacroLineNos568.my_fun() == 30
         rm_precompile("MacroLineNos568")
 
+        # Macros that create empty functions (another macro *execution* bug, issue #792)
+        file = tempname()
+        write(file, "@empty_function issue792f1\n")
+        sleep(mtimedelay)
+        includet(ReviseTestPrivate, file)
+        sleep(mtimedelay)
+        @test isempty(methods(ReviseTestPrivate.issue792f1))
+        open(file, "a") do f
+            println(f, "@empty_function issue792f2")
+        end
+        yry()
+        @test isempty(methods(ReviseTestPrivate.issue792f2))
+        rm(file)
+
         pop!(LOAD_PATH)
     end