add support for --dump-input flag (fixes #19)

filecheck/help.py

@@ -12,6 +12,11 @@
                                   match.
 --match-full-lines              : Expect every check line to match the whole line.
 --reject-empty-vars             : Raise an error when a value captures an empty string.
+--dump-intput                   : Dump the input to stderr annotated with helpful
+                                  information depending on the context. Allowed values
+                                  are help, always, never, fail. Default is fail.
+                                  Only fail and never is currently supported in this
+                                  version of filecheck.
 
 ARGUMENTS:
 check-file                      : The file from which the check lines are to be read

filecheck/matcher.py

@@ -1,16 +1,17 @@
 import re
+import os
 import sys
 from collections.abc import Sequence
 from dataclasses import dataclass, field
-from typing import Callable
+from typing import Callable, TextIO
 
 from filecheck.compiler import compile_uops
 from filecheck.error import CheckError, ParseError, ErrorOnMatch
 from filecheck.finput import FInput, InputRange
 from filecheck.logging import warn
 from filecheck.colors import ERR, FMT
 from filecheck.ops import CheckOp, CountOp, Literal, Subst, UOp, RE, Capture
-from filecheck.options import Options
+from filecheck.options import Options, DumpInputKind
 from filecheck.parser import Parser
 from filecheck.preprocess import Preprocessor
 
@@ -45,6 +46,8 @@ class Matcher:
 
     ctx: Context = field(default_factory=Context)
 
+    stderr: TextIO = field(init=False)
+
     @classmethod
     def from_opts(cls, opts: Options):
         """
@@ -56,6 +59,15 @@ def from_opts(cls, opts: Options):
 
     def __post_init__(self):
         self.ctx.live_variables.update(self.opts.variables)
+        if self.opts.dump_input == DumpInputKind.NEVER:
+            self.stderr = open(os.devnull, "w")
+        else:
+            self.stderr = sys.stderr
+        if self.opts.dump_input in (DumpInputKind.ALWAYS, DumpInputKind.HELP):
+            warn(
+                f"Unsupported dump-input flag: {self.opts.dump_input.name.lower()}",
+                opts=self.opts,
+            )
 
     def run(self) -> int:
         """
@@ -67,7 +79,7 @@ def run(self) -> int:
             if self.file.content in ("", "\n"):
                 print(
                     f"{ERR}filecheck error:{FMT.RESET} '{self.opts.readable_input_file()}' is empty.",
-                    file=sys.stderr,
+                    file=self.stderr,
                 )
                 return 1
 
@@ -81,16 +93,16 @@ def run(self) -> int:
                     pref = f"prefixes {', '.join(self.opts.check_prefixes)}"
                 print(
                     f"{ERR}filecheck error:{FMT.RESET} No check strings found with {pref}:",
-                    file=sys.stderr,
+                    file=self.stderr,
                 )
                 return 2
         except ParseError as ex:
             print(
                 f"{self.opts.match_filename}:{ex.line_no}:{ex.offset} {ex.message}",
-                file=sys.stderr,
+                file=self.stderr,
             )
-            print(ex.offending_line.rstrip("\n"), file=sys.stderr)
-            print(" " * (ex.offset - 1) + "^", file=sys.stderr)
+            print(ex.offending_line.rstrip("\n"), file=self.stderr)
+            print(" " * (ex.offset - 1) + "^", file=self.stderr)
             return 1
 
         function_table: dict[str, Callable[[CheckOp], None]] = {
@@ -122,40 +134,40 @@ def run(self) -> int:
         except CheckError as ex:
             print(
                 f"{self.opts.match_filename}:{ex.op.source_line}: {ERR}error:{FMT.RESET} {ex.message}",
-                file=sys.stderr,
+                file=self.stderr,
             )
-            print("Current position at " + self.file.print_line(), file=sys.stderr)
+            print("Current position at " + self.file.print_line(), file=self.stderr)
 
             if self.file.is_discontigous():
                 print(
                     "\nCurrently matching in range (grey is already matched):",
-                    file=sys.stderr,
+                    file=self.stderr,
                 )
-                print("".join(self.file.print_current_range()), file=sys.stderr)
+                print("".join(self.file.print_current_range()), file=self.stderr)
 
             # try to look for a shorter match, and print that if possible
             prefix_match = self.find_prefix_match_for(ex.op)
             if prefix_match is not None:
-                print("Possible intended match at:", file=sys.stderr)
-                print(self.file.print_line(prefix_match.start(0)), file=sys.stderr)
+                print("Possible intended match at:", file=self.stderr)
+                print(self.file.print_line(prefix_match.start(0)), file=self.stderr)
 
             return 1
         except ErrorOnMatch as ex:
             print(
                 f"{self.opts.match_filename}:{ex.op.source_line}: {ERR}error:{FMT.RESET} {ex.message}",
-                file=sys.stderr,
+                file=self.stderr,
             )
-            print("Matching at: ", end="", file=sys.stderr)
+            print("Matching at: ", end="", file=self.stderr)
             print(
                 self.file.print_line(ex.match.start(0), ex.match.end(0)),
-                file=sys.stderr,
+                file=self.stderr,
             )
             if self.file.is_discontigous():
                 print(
                     "\nCurrently matching in range (grey is already matched):",
-                    file=sys.stderr,
+                    file=self.stderr,
                 )
-                print("".join(self.file.print_current_range()), file=sys.stderr)
+                print("".join(self.file.print_current_range()), file=self.stderr)
             return 1
 
         return 0

filecheck/options.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass, field
-from enum import Enum
+from enum import Enum, auto
 from typing import Iterable
 import os
 
@@ -8,6 +8,13 @@ class Extension(Enum):
     MLIR_REGEX_CLS = "MLIR_REGEX_CLS"
 
 
+class DumpInputKind(Enum):
+    HELP = auto()
+    ALWAYS = auto()
+    NEVER = auto()
+    FAIL = auto()
+
+
 @dataclass
 class Options:
     match_filename: str
@@ -19,6 +26,7 @@ class Options:
     match_full_lines: bool = False
     allow_empty: bool = False
     reject_empty_vars: bool = False
+    dump_input: DumpInputKind = DumpInputKind.FAIL
     variables: dict[str, str | int] = field(default_factory=dict)
 
     extensions: set[Extension] = field(default_factory=set)
@@ -32,7 +40,7 @@ def __post_init__(self):
         extensions: set[Extension] = set()
         for ext in self.extensions:
             if isinstance(ext, str):
-                if ext in set(e.name for e in Extension):
+                if ext in set(e.value for e in Extension):
                     extensions.add(
                         Extension[ext]  # pyright: ignore[reportArgumentType]
                     )
@@ -43,6 +51,14 @@ def __post_init__(self):
             else:
                 extensions.add(ext)
         self.extensions = extensions
+        if isinstance(self.dump_input, str):
+            name: str = self.dump_input.upper()
+            if name in set(d.name for d in DumpInputKind):
+                self.dump_input = DumpInputKind[name]
+            else:
+                raise RuntimeError(
+                    f'Unknown value supplied for dump-input flag: "{name}"'
+                )
 
     def readable_input_file(self):
         if self.input_file == "-":

tests/filecheck/flags/dump-input.test

@@ -0,0 +1,12 @@
+// RUN: strip-comments.sh %s | filecheck %s --dump-input never --check-prefix RIGHT | filecheck %s --allow-empty --check-prefix EMPTY
+// RUN: strip-comments.sh %s | exfail filecheck %s --dump-input never --check-prefix WRONG | filecheck %s --allow-empty --check-prefix EMPTY
+// RUN: strip-comments.sh %s | filecheck %s --dump-input fail --check-prefix RIGHT | filecheck %s --allow-empty --check-prefix EMPTY
+// RUN: strip-comments.sh %s | exfail filecheck %s --dump-input fail --check-prefix WRONG | filecheck %s --allow-empty --check-prefix HAS-OUTPUT
+// RUN: strip-comments.sh %s | filecheck %s --dump-input help --check-prefix RIGHT 2>&1 | filecheck %s --allow-empty --check-prefix UNKNOWN-FLAG -DFLAG=help
+// RUN: strip-comments.sh %s | filecheck %s --dump-input always --check-prefix RIGHT 2>&1 | filecheck %s --allow-empty --check-prefix UNKNOWN-FLAG -DFLAG=always
+test
+// RIGHT: test
+// WRONG: wrong
+// EMPTY-NOT: {{.+}}
+// HAS-OUTPUT: error: Couldn't match "wrong".
+// UNKNOWN-FLAG: Warning: Unsupported dump-input flag: [[FLAG]]