improve message for missing keys

src/qtoolkit/io/base.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import abc
+import difflib
 import shlex
 from dataclasses import fields
 from pathlib import Path
@@ -82,9 +83,27 @@ def generate_header(self, options: dict | QResources | None) -> str:
 
         # check that all the options are present in the template
         keys = set(options.keys())
-        extra = keys.difference(template.get_identifiers())
+        all_identifiers = template.get_identifiers()
+        extra = keys.difference(all_identifiers)
         if extra:
-            msg = f"The following keys are not present in the template: {', '.join(sorted(extra))}"
+            close_matches = {}
+            for extra_val in extra:
+                m = difflib.get_close_matches(
+                    extra_val, all_identifiers, n=3, cutoff=0.65
+                )
+                if m:
+                    close_matches[extra_val] = m
+            msg = (
+                f"The following keys are not present in the template: {', '.join(sorted(extra))}. "
+                f"Check the template in {type(self).__module__}.{type(self).__qualname__}.header_template."
+            )
+            if close_matches:
+                msg += " Possible replacements:"
+                for extra_val in sorted(close_matches):
+                    replacements = " or ".join(
+                        f"'{m}'" for m in close_matches[extra_val]
+                    )
+                    msg += f" {replacements} instead of '{extra_val}'."
             raise ValueError(msg)
 
         unclean_header = template.safe_substitute(options)

tests/io/test_base.py

@@ -144,9 +144,12 @@ def test_generate_header(self, scheduler):
 #SPECCMD --nodes=4"""
         )
 
+        # check that the error message contains the expected error, but should not match
+        # the possible replacements, as they are too different
         with pytest.raises(
             ValueError,
-            match=r"The following keys are not present in the template: tata, titi",
+            match=r"The following keys are not present in the template: tata, titi. Check "
+            r"the template in .*MyScheduler.header_template(?!.*instead of 'titi')",
         ):
             res = QResources(
                 nodes=4,
@@ -155,6 +158,19 @@ def test_generate_header(self, scheduler):
             )
             scheduler.generate_header(res)
 
+        with pytest.raises(
+            ValueError,
+            match=r"The following keys are not present in the template: option32, processes-per-node. "
+            r"Check the template in .*MyScheduler.header_template.*'option3' or 'option2' or 'option1' "
+            r"instead of 'option32'. 'processes_per_node' or 'processes' instead of 'processes-per-node'",
+        ):
+            res = QResources(
+                nodes=4,
+                processes_per_node=16,
+                scheduler_kwargs={"option32": "xxx", "processes-per-node": "yyy"},
+            )
+            scheduler.generate_header(res)
+
     def test_generate_ids_list(self, scheduler):
         ids_list = scheduler.generate_ids_list(
             [QJob(job_id=4), QJob(job_id="job_id_abc1"), 215, "job12345"]