Improve message error for when Crytic throws a KeyError. (#2418)

* Improve message error for when Crytic throws a KeyError.

* Remove unneeded logger usage and fix typo

slither/core/source_mapping/source_mapping.py

@@ -4,6 +4,7 @@
 from Crypto.Hash import SHA1
 from crytic_compile.utils.naming import Filename
 from slither.core.context.context import Context
+from slither.exceptions import SlitherException
 
 if TYPE_CHECKING:
     from slither.core.compilation_unit import SlitherCompilationUnit
@@ -136,9 +137,20 @@ def _compute_line(
     start_line, starting_column = compilation_unit.core.crytic_compile.get_line_from_offset(
         filename, start
     )
-    end_line, ending_column = compilation_unit.core.crytic_compile.get_line_from_offset(
-        filename, start + length
-    )
+    try:
+        end_line, ending_column = compilation_unit.core.crytic_compile.get_line_from_offset(
+            filename, start + length
+        )
+    except KeyError:
+        # This error may occur when the build is not synchronised with the source code on disk.
+        # See the GitHub issue https://github.com/crytic/slither/issues/2296
+        msg = f"""The source code appears to be out of sync with the build artifacts on disk.
+        This discrepancy can occur after recent modifications to {filename.short}. To resolve this
+        issue, consider executing the clean command of the build system (e.g. forge clean).
+        """
+        # We still re-raise the exception as a SlitherException here
+        raise SlitherException(msg) from None
+
     return list(range(start_line, end_line + 1)), starting_column, ending_column
 
 

tests/e2e/compilation/test_data/test_change/README.md

@@ -0,0 +1,3 @@
+# Foundry
+
+To init this test case, run `forge install --no-commit --no-git foundry-rs/forge-std`

tests/e2e/compilation/test_data/test_change/foundry.toml

@@ -0,0 +1,6 @@
+[profile.default]
+src = "src"
+out = "out"
+libs = ["lib"]
+
+# See more config options https://github.com/foundry-rs/foundry/blob/master/crates/config/README.md#all-options

tests/e2e/compilation/test_data/test_change/src/Counter.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+contract Counter {
+    uint256 public number;
+
+    function setNumber(uint256 newNumber) public {
+        number = newNumber;
+    }
+
+    //START
+    function increment() public {
+        number++;
+    }
+    //END
+}

tests/e2e/compilation/test_diagnostic.py

@@ -0,0 +1,40 @@
+from pathlib import Path
+import shutil
+import re
+
+import pytest
+
+from slither import Slither
+from slither.exceptions import SlitherException
+
+
+TEST_DATA_DIR = Path(__file__).resolve().parent / "test_data"
+
+foundry_available = shutil.which("forge") is not None
+project_ready = Path(TEST_DATA_DIR, "test_change/lib/forge-std").exists()
+
+
+@pytest.mark.skipif(
+    not foundry_available or not project_ready, reason="requires Foundry and project setup"
+)
+def test_diagnostic():
+
+    test_file_directory = TEST_DATA_DIR / "test_change"
+
+    sl = Slither(test_file_directory.as_posix())
+    assert len(sl.compilation_units) == 1
+
+    counter_file = test_file_directory / "src" / "Counter.sol"
+    shutil.copy(counter_file, counter_file.with_suffix(".bak"))
+
+    with counter_file.open("r") as file:
+        content = file.read()
+
+    with counter_file.open("w") as file:
+        file.write(re.sub(r"//START.*?//END\n?", "", content, flags=re.DOTALL))
+
+    with pytest.raises(SlitherException):
+        Slither(test_file_directory.as_posix(), ignore_compile=True)
+
+    # Restore the original counter so the test is idempotent
+    Path(counter_file.with_suffix(".bak")).rename(counter_file)