From b6f20aeac0b81c23d64deef827a67b38631b593a Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Sat, 2 Mar 2019 06:10:58 -0600
Subject: [PATCH] Add some convenience methods for line number correction

---
 README.md           | 11 +++++++++--
 src/CodeTracking.jl | 26 ++++++++++++++++++++++++++
 test/runtests.jl    | 12 +++++++++++-
 test/script.jl      |  8 ++++++++
 4 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 45e1cf1..665b7e1 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 CodeTracking is a minimal package designed to work with (a future version of)
 [Revise.jl](https://github.com/timholy/Revise.jl).
 Its main purpose is to support packages that need to interact with code that might move
-around as it's edited.
+around as it gets edited.
 
 CodeTracking is a very lightweight dependency.
 
@@ -23,7 +23,10 @@ In this (ficticious) example, `sum` moved because I deleted a few lines higher i
 these didn't affect the functionality of `sum` (so we didn't need to redefine and recompile it),
 but it does change the starting line number of the file at which this method appears.
 
-Other features:
+Other methods of `whereis` allow you to obtain the current position corresponding to a single
+statement inside a method; see `?whereis` for details.
+
+CodeTracking can also be used to find out what files define a particular package:
 
 ```julia
 julia> using CodeTracking, ColorTypes
@@ -32,7 +35,11 @@ julia> pkgfiles(ColorTypes)
 PkgFiles(ColorTypes [3da002f7-5984-5a60-b8a6-cbb66c0b333f]):
   basedir: /home/tim/.julia/packages/ColorTypes/BsAWO
   files: ["src/ColorTypes.jl", "src/types.jl", "src/traits.jl", "src/conversions.jl", "src/show.jl", "src/operations.jl"]
+```
 
+or to extract the expression that defines a method:
+
+```julia
 julia> m = @which red(RGB(1,1,1))
 red(c::AbstractRGB) in ColorTypes at /home/tim/.julia/packages/ColorTypes/BsAWO/src/traits.jl:14
 
diff --git a/src/CodeTracking.jl b/src/CodeTracking.jl
index 0978705..6e94a4c 100644
--- a/src/CodeTracking.jl
+++ b/src/CodeTracking.jl
@@ -41,6 +41,32 @@ function whereis(method::Method)
     return normpath(file), line
 end
 
+"""
+    loc = whereis(sf::StackFrame)
+
+Return location information for a single frame of a stack trace.
+If `sf` corresponds to a frame that was inlined, `loc` will be `nothing`.
+Otherwise `loc` will be `(filepath, line)`.
+"""
+function whereis(sf::StackTraces.StackFrame)
+    sf.linfo === nothing && return nothing
+    return whereis(sf, sf.linfo.def)
+end
+
+"""
+    filepath, line = whereis(lineinfo, method::Method)
+
+Return the file and line number associated with a specific statement in `method`.
+`lineinfo.line` should contain the line number of the statement at the time `method`
+was compiled. The current location is returned.
+"""
+function whereis(lineinfo, method::Method)
+    file, line1 = whereis(method)
+    return file, lineinfo.line-method.line+line1
+end
+
+
+
 """
     src = definition(method::Method, String)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 68bc11f..10a3b43 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -7,7 +7,17 @@ include("script.jl")
 @testset "CodeTracking.jl" begin
     m = first(methods(f1))
     file, line = whereis(m)
-    @test file == normpath(joinpath(@__DIR__, "script.jl"))
+    scriptpath = normpath(joinpath(@__DIR__, "script.jl"))
+    @test file == scriptpath
+    @test line == 3
+    trace = try
+        call_throws()
+    catch
+        stacktrace(catch_backtrace())
+    end
+    @test whereis(trace[2]) == (scriptpath, 10)
+    @test whereis(trace[3]) === nothing
+
     src = definition(m, String)
     @test src == """
     function f1(x, y)
diff --git a/test/script.jl b/test/script.jl
index 49f08f4..b3a0eb7 100644
--- a/test/script.jl
+++ b/test/script.jl
@@ -1,5 +1,13 @@
+# NOTE: tests are sensitive to the line number at which statements appear
 function f1(x, y)
     return x + y
 end
 
 f2(x, y) = x + y
+
+@noinline function throws()
+    x = nothing
+    error("oops")
+end
+@inline inlined() = throws()
+call_throws() = inlined()