Fix parser comparison tool. stdlib now parses for 1.6 - 1.8 (#9)

It turns out that SparseArrays has some unused .jl files in the tests
with broken syntax in 1.8 dev. Fix the JuliaSyntax parser comparison
tool to ignore these cases.

Author: c42f

src/parser.jl

@@ -2677,7 +2677,6 @@ end
 #   tightest:  ... < `;;;` < `;;` < `;`,`\n` < whitespace. We choose binding
 #   power of 0 for whitespace and negative numbers for other separators.
 #
-# FIXME: Error messages for mixed spaces and ;; delimiters
 function parse_array_separator(ps, array_order)
     sep_mismatch_err = "cannot mix space and ;; separators in an array expression, except to wrap a line"
     mark = position(ps)

test/parse_packages.jl

@@ -21,9 +21,6 @@ end
 
 end
 
-if VERSION < v"1.8-DEV" || haskey(ENV, "PARSE_STDLIB")
-# TODO: Fix on 1.8
-
 @testset "Parse Julia stdlib at $(Sys.STDLIB)" begin
     for stdlib in readdir(Sys.STDLIB)
         fulldir = joinpath(Sys.STDLIB, stdlib)
@@ -34,5 +31,3 @@ if VERSION < v"1.8-DEV" || haskey(ENV, "PARSE_STDLIB")
         end
     end
 end
-
-end

test/test_utils.jl

@@ -38,11 +38,30 @@ function remove_all_linenums!(ex)
     remove_macro_linenums!(ex)
 end
 
-function parsers_agree_on_file(path)
-    text = read(path, String)
-    ex = parseall(Expr, text, filename=path)
-    fl_ex = flisp_parse_all(text, filename=path)
-    JuliaSyntax.remove_linenums!(ex) == JuliaSyntax.remove_linenums!(fl_ex)
+function parsers_agree_on_file(filename)
+    text = try
+        read(filename, String)
+    catch
+        # Something went wrong reading the file. This isn't a parser failure so
+        # ignore this case.
+        return true
+    end
+    fl_ex = flisp_parse_all(text, filename=filename)
+    if Meta.isexpr(fl_ex, :toplevel) && !isempty(fl_ex.args) &&
+            Meta.isexpr(fl_ex.args[end], (:error, :incomplete))
+        # Reference parser failed. This generally indicates a broken file not a
+        # parser problem, so ignore this case.
+        return true
+    end
+    try
+        ex, diagnostics, _ = parse(Expr, text, filename=filename)
+        return !JuliaSyntax.any_error(diagnostics) &&
+            JuliaSyntax.remove_linenums!(ex) ==
+            JuliaSyntax.remove_linenums!(fl_ex)
+    catch exc
+        @error "Parsing failed" path exception=current_exceptions()
+        return false
+    end
 end
 
 function find_source_in_path(basedir)
@@ -155,7 +174,7 @@ function reduce_all_failures_in_path(basedir, outdir)
     rm(outdir, force=true, recursive=true)
     mkpath(outdir)
     for filename in find_source_in_path(basedir)
-        if !(try parsers_agree_on_file(filename) catch exc false end)
+        if !parsers_agree_on_file(filename)
             @info "Found failure" filename
             bn,_ = splitext(basename(filename))
             outname = joinpath(outdir, "$bn.jl")