Additional fix + tests

JuliaLang · Oct 6, 2020 · d2f65db · d2f65db
1 parent 467ae38
commit d2f65db
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/stdlib/Printf/src/Printf.jl b/stdlib/Printf/src/Printf.jl
@@ -80,10 +80,19 @@ function Format(f::AbstractString)
     len = length(bytes)
     pos = 1
     b = 0x00
-    while true
+    while pos <= len
         b = bytes[pos]
         pos += 1
-        (pos > len || (b == UInt8('%') && pos <= len && bytes[pos] != UInt8('%'))) && break
+        if b == UInt8('%')
+            pos > len && throw(ArgumentError("invalid format string: '$f'"))
+            if bytes[pos] == UInt8('%')
+                # escaped '%'
+                b = bytes[pos]
+                pos += 1
+            else
+                break
+            end
+        end
     end
     strs = [1:pos - 1 - (b == UInt8('%'))]
     fmts = []

diff --git a/stdlib/Printf/test/runtests.jl b/stdlib/Printf/test/runtests.jl
@@ -303,6 +303,12 @@ end
 @testset "basics" begin
 
     @test Printf.@sprintf("%%") == "%"
+    @test Printf.@sprintf("1%%") == "1%"
+    @test Printf.@sprintf("%%1") == "%1"
+    @test Printf.@sprintf("1%%2") == "1%2"
+    @test Printf.@sprintf("1%%%d", 2) == "1%2"
+    @test Printf.@sprintf("1%%2%%3") == "1%2%3"
+    @test Printf.@sprintf("GAP[%%]") == "GAP[%]"
     @test Printf.@sprintf("hey there") == "hey there"
     @test_throws ArgumentError Printf.Format("")
     @test_throws ArgumentError Printf.Format("%+")