const hints - improve error detecting and reporting

README.md

@@ -354,8 +354,6 @@ objs={4,6,6,5}
 ?2
 ```
 
-Keep in mind that *Local* variables that aren't declared as `--[[const]]` may still be treated as constants in cases where it's safe & advantageous to do so.
-
 Furthermore, constant `if` and `elseif` branches are removed appropriately, allowing you to easily keep debug code in your source files, enabling it by simply changing the value of a variable:
 
 ```lua
@@ -371,6 +369,12 @@ end
 spr(debug_spr,10,10)
 ```
 
+Some details to keep in mind:
+* *Local* variables that **aren't** declared as `--[[const]]` may still be treated as constants in cases where it's safe & advantageous to do so.
+* *Local* variables that **are** declared as `--[[const]]` still follow the usual lua scoping rules. They cannot be reassigned but new locals with the same name can be defined.
+* *Global* variables that **aren't** declared as `--[[const]]` are currently never treated as constants.
+* *Global* variables that **are** declared as `--[[const]]` are assumed to *always* have their constant value. They cannot be reassigned and can only be used below their declaration.
+
 ## Passing constants via command line
 
 You can even declare constants in the command line, if you prefer:

pico_constfold.py

@@ -474,8 +474,12 @@ def update_node_constval(node):
                         else:
                             set_const(node, constval)
 
-        elif node.type == NodeType.var and node.var and node.var.constval and not node.new and not node.assignment:
-            set_const(node, node.var.constval)
+        elif node.type == NodeType.var and node.var and not node.new and not node.assignment:
+            if node.var.constval:
+                set_const(node, node.var.constval)
+            elif node.var.is_const:
+                add_error(f"'{node.name}' is marked as constant but is used above where it is assigned to", node)
+                node.var.is_const = False
 
         elif node.type in (NodeType.local, NodeType.assign):
             visit_assign(node)
@@ -570,7 +574,10 @@ def visit_assign(node):
                     reason = ""
                     if const_ctxt_fail:
                         reason = f" due to '{const_ctxt_fail.source_text}'"
+                    elif not is_const:
+                        reason = f" due to being reassigned"
                     add_error(f"Local '{target.name}' is marked as const but its value cannot be determined" + reason, target)
+                    target.var.is_const = False
 
             if is_const_ctxt:
                 in_const_ctxt -= 1

run_tests.py

@@ -42,7 +42,7 @@ def try_read_dir_contents(dir):
     return results
 
 def run_test(name, input, output, *args, private=False, check_output=True, from_output=False,
-             read_stdout=False, norm_stdout=nop, exit_code=0, extra_outputs=None, output_reader=try_file_read,
+             stdout_output=None, norm_stdout=nop, exit_code=0, extra_outputs=None, output_reader=try_file_read,
              pico8_output_val=None, pico8_output=None, pico8_run=None, copy_in_to_out=False):
     if g_opts.test:
         for wanted_test in g_opts.test:
@@ -59,15 +59,16 @@ def run_test(name, input, output, *args, private=False, check_output=True, from_
     start_test()
     prefix = "private_" if private else ""
     inpath = path_join(prefix + ("test_output" if from_output else "test_input"), input)
-    outpath = path_join(prefix + "test_output", output)
-    cmppath = path_join(prefix + "test_compare", output)
+    if output:
+        outpath = path_join(prefix + "test_output", output)
+        cmppath = path_join(prefix + "test_compare", output)
 
     if copy_in_to_out:
         file_write(outpath, file_read(path_join(path_dirname(inpath), output)))
 
     if not input:
         args = (outpath,) + args
-    elif read_stdout:
+    elif not output:
         args = (inpath,) + args
     else:
         args = (inpath, outpath) + args
@@ -76,20 +77,26 @@ def run_test(name, input, output, *args, private=False, check_output=True, from_
     success = run_success
     stdouts = [run_stdout]
 
-    if read_stdout:
-        file_write_text(outpath, norm_stdout(run_stdout))
-
-    if run_success and check_output:
+    if run_success and output and check_output:
         if output_reader(outpath) != output_reader(cmppath):
-            stdouts.append(f"ERROR: File difference: {outpath}, {cmppath}")
+            stdouts.append(f"ERROR: Output difference: {outpath}, {cmppath}")
+            success = False
+
+    if run_success and stdout_output:
+        stdout_outpath = path_join(prefix + "test_output", stdout_output)
+        stdout_cmppath = path_join(prefix + "test_compare", stdout_output)
+        run_stdout = norm_stdout(run_stdout)
+        file_write_text(stdout_outpath, run_stdout)
+        if run_stdout != try_file_read_text(stdout_cmppath):
+            stdouts.append(f"ERROR: Stdout difference: {stdout_outpath}, {stdout_cmppath}")
             success = False
 
     if run_success and extra_outputs:
         for extra_output in extra_outputs:
             extra_outpath = path_join(prefix + "test_output", extra_output)
             extra_cmppath = path_join(prefix + "test_compare", extra_output)
             if try_file_read(extra_outpath) != try_file_read(extra_cmppath):
-                stdouts.append(f"ERROR: Extra file difference: {extra_outpath}, {extra_cmppath}")
+                stdouts.append(f"ERROR: Extra output difference: {extra_outpath}, {extra_cmppath}")
                 success = False
 
     if run_success and g_opts.pico8 and not g_opts.no_pico8 and (pico8_output != None or pico8_output_val != None or pico8_run):
@@ -108,7 +115,7 @@ def run_test(name, input, output, *args, private=False, check_output=True, from_
         print(f"\nERROR - test {name} failed")
         print(f"Args: {args}")
         print(stdout)
-        if not read_stdout and not g_opts.no_measure:
+        if output and not g_opts.no_measure:
             measure("new", outpath)
             measure("old", cmppath)
         fail_test()
@@ -123,9 +130,6 @@ def run_test(name, input, output, *args, private=False, check_output=True, from_
         print(stdout)
     return True
 
-def run_stdout_test(name, input, *args, output=None, **kwargs):
-    run_test(name, input, output, *args, **kwargs, read_stdout=True)
-
 def run():
     if run_test("minify", "input.p8", "output.p8", "--minify", "--no-minify-consts",
                 "--preserve", "*.preserved_key,preserved_glob,preserving_obj.*", pico8_output="output.p8.printh"):
@@ -157,7 +161,7 @@ def run():
              pico8_run=True)
     run_test("const2", "const2.p8", "const2.p8", "--minify",
              "--no-minify-spaces", "--no-minify-lines", "--no-minify-comments", "--no-minify-rename", "--no-minify-tokens",
-             pico8_run=True)
+             pico8_run=True, stdout_output="const2.txt", norm_stdout=norm_paths)
     run_test("constcl", "constcl.p8", "constcl.p8", "--minify")
     run_test("constcl-1", "constcl.p8", "constcl-1.p8", "--minify", "--const", "DEBUG", "true", "--const", "SPEED", "2.5", "--str-const", "VERSION", "v1.2")
     run_test("constcl-2", "constcl.p8", "constcl-2.p8", "--minify", "--const", "DEBUG", "true", "--const", "SPEED", "-2.6", "--const", "hero", "~1")
@@ -193,16 +197,16 @@ def run():
     run_test("default", "default.p8", "default.rom")
     run_test("default2", "default2.p8", "default2.rom")
     run_test("genend", "genend.p8.png", "genend.p8")
-    run_stdout_test("lint", "bad.p8", "--lint", output="bad.txt", norm_stdout=norm_paths, exit_code=2)
-    run_stdout_test("linttab", "bad.p8", "--lint", "--error-format", "tabbed",
-                    output="bad-tab.txt", norm_stdout=norm_paths, exit_code=2)
-    run_stdout_test("count", "bad.p8", "--count", output="badcount.txt")
-    run_stdout_test("countminus", "minus.p8", "--count", output="minuscount.txt")
-    run_stdout_test("error", "worse.p8", "--lint", output="worse.txt", norm_stdout=norm_paths, exit_code=1)
+    run_test("lint", "bad.p8", None, "--lint", stdout_output="bad.txt", norm_stdout=norm_paths, exit_code=2)
+    run_test("linttab", "bad.p8", None, "--lint", "--error-format", "tabbed",
+             stdout_output="bad-tab.txt", norm_stdout=norm_paths, exit_code=2)
+    run_test("count", "bad.p8", None, "--count", stdout_output="badcount.txt")
+    run_test("countminus", "minus.p8", None, "--count", stdout_output="minuscount.txt")
+    run_test("error", "worse.p8", None, "--lint", stdout_output="worse.txt", norm_stdout=norm_paths, exit_code=1)
     run_test("script", "script.p8", "script.p8", "--script", path_join("test_input", "my_script.py"),
              "--script-args", "my-script-arg", "--my-script-opt", "123")
-    run_stdout_test("sublang.lint", "sublang.p8", "--lint",
-             "--script", path_join("test_input", "sublang.py"), output="sublang.txt", norm_stdout=norm_paths, exit_code=2)
+    run_test("sublang.lint", "sublang.p8", None, "--lint",
+             "--script", path_join("test_input", "sublang.py"), stdout_output="sublang.txt", norm_stdout=norm_paths, exit_code=2)
     run_test("sublang", "sublang.p8", "sublang.p8", "--minify",
              "--script", path_join("test_input", "sublang.py"))
     run_test("unkform1", "unkform1", "unkform1")

shrinko8.py

@@ -8,7 +8,7 @@
 from pico_constfold import parse_constant
 import argparse
 
-k_version = 'v1.2.0b'
+k_version = 'v1.2.0c'
 
 def SplitBySeps(val):
     return k_hint_split_re.split(val)

test_compare/const2.p8

@@ -4,6 +4,7 @@ __lua__
 stop() -- for pure syntax check
 _ENV["min"]=123
 function x()
+    ?ssog4
     function max()
     end
     local function min()
@@ -21,3 +22,7 @@ local M,m = max(1,2),min(1,2)
 --[[preserve]]ssog1 = 123; ?ssog1
 --[[const]]; ?123
 --[[const]]ssog3 = 123; ssog3 += 1; ?ssog3
+--[[const]]ssog4 = 4; ?ssog4
+--[[const]]ssog5 = ssog5; ?ssog5
+--[[const]]ssog6 = 123; --[[const]]ssog6 = 456; ?ssog6
+--[[const]] ?2

test_compare/const2.txt

@@ -0,0 +1,9 @@
+Hint usage warnings:
+test_input/const2.p8:7:6: 'ssog4' is marked as constant but is used above where it is assigned to
+test_input/const2.p8:12:23: Local 'M' is marked as const but its value cannot be determined due to 'max(1,2)'
+test_input/const2.p8:12:25: Local 'm' is marked as const but its value cannot be determined due to 'min(1,2)'
+test_input/const2.p8:16:19: Local 'M' is marked as const but its value cannot be determined due to 'max(1,2)'
+test_input/const2.p8:24:12: Local 'ssog3' is marked as const but its value cannot be determined due to being reassigned
+test_input/const2.p8:26:12: Local 'ssog5' is marked as const but its value cannot be determined due to 'ssog5'
+test_input/const2.p8:26:20: 'ssog5' is marked as constant but is used above where it is assigned to
+test_input/const2.p8:27:12: Local 'ssog6' is marked as const but its value cannot be determined due to being reassigned

test_input/const2.p8

@@ -4,6 +4,7 @@ __lua__
 stop() -- for pure syntax check
 _ENV["min"]=123
 function x()
+    ?ssog4
     function max()
     end
     local function min()
@@ -20,4 +21,10 @@ local M,m = max(1,2),min(1,2)
 ?m
 --[[preserve]]ssog1 = 123; ?ssog1
 --[[const]]ssog2 = 123; ?ssog2
---[[const]]ssog3 = 123; ssog3 += 1; ?ssog3
+--[[const]]ssog3 = 123; ssog3 += 1; ?ssog3
+--[[const]]ssog4 = 4; ?ssog4
+--[[const]]ssog5 = ssog5; ?ssog5
+--[[const]]ssog6 = 123; --[[const]]ssog6 = 456; ?ssog6
+--[[const]] local cc = 1
+--[[const]] local cc = cc + 1
+?cc