Darker diffs should be apply-able, or command should autofix

[keith]

I got this great python formatter comment on my PR:

#105759 (comment)

copied content in case it gets deleted:

⚠️ Python code formatter, darker found issues in your code. ⚠️

You can test this locally with the following command:

darker --check --diff -r 09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354 llvm/utils/lit/lit/TestRunner.py

View the diff from darker here.

--- TestRunner.py	2024-08-23 00:57:43.000000 +0000
+++ TestRunner.py	2024-08-23 01:04:52.524386 +0000
@@ -1222,12 +1222,14 @@
                     commands[i] += f" && {{ {command}; }}"
         if test.config.pipefail:
             f.write(b"set -o pipefail;" if mode == "wb" else "set -o pipefail;")
         f.write(b"set -x;" if mode == "wb" else "set -x;")
 
-        env_str = "\n".join("export {}={};".format(k, shlex.quote(v))
-                            for k, v in test.config.environment.items())
+        env_str = "\n".join(
+            "export {}={};".format(k, shlex.quote(v))
+            for k, v in test.config.environment.items()
+        )
         f.write(bytes(env_str, "utf-8") if mode == "wb" else env_str)
 
         if sys.version_info > (3, 0) and mode == "wb":
             f.write(bytes("{ " + "; } &&\n{ ".join(commands) + "; }", "utf-8"))
         else:

But neither this command or diff are exactly what I was hoping for. I was hoping that either the darker command could be updated to just apply the diff, which it doesn't seem like it can:

darker 09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354 llvm/utils/lit/lit/TestRunner.py
argument PATH: Error: Path(s) '09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354' do not exist in the working tree

Or I'd be able to copy and paste the diff contents and run git apply which I cannot because the path is not TestRunner.py, so git is expecting it to be llvm/utils/lit/lit/TestRunner.py. If I manually update the paths in the diff to be:

--- a/llvm/utils/lit/lit/TestRunner.py
+++ b/llvm/utils/lit/lit/TestRunner.py

Then applying it works, but I think it would be nice if either of these options worked without this extra step.

I might be missing another command line flag here too, in which case I think it would be nice to add the automatic fix instructions to the comment

[llvmbot]

@llvm/issue-subscribers-infrastructure

Author: Keith Smiley (keith)

I got this great python formatter comment on my PR:

#105759 (comment)

copied content in case it gets deleted:

<!--LLVM CODE FORMAT COMMENT: {darker}-->

⚠️ Python code formatter, darker found issues in your code. ⚠️

<details>
<summary>
You can test this locally with the following command:
</summary>

darker --check --diff -r 09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354 llvm/utils/lit/lit/TestRunner.py

</details>

<details>
<summary>
View the diff from darker here.
</summary>

--- TestRunner.py	2024-08-23 00:57:43.000000 +0000
+++ TestRunner.py	2024-08-23 01:04:52.524386 +0000
@@ -1222,12 +1222,14 @@
                     commands[i] += f" && {{ {command}; }}"
         if test.config.pipefail:
             f.write(b"set -o pipefail;" if mode == "wb" else "set -o pipefail;")
         f.write(b"set -x;" if mode == "wb" else "set -x;")
 
-        env_str = "\n".join("export {}={};".format(k, shlex.quote(v))
-                            for k, v in test.config.environment.items())
+        env_str = "\n".join(
+            "export {}={};".format(k, shlex.quote(v))
+            for k, v in test.config.environment.items()
+        )
         f.write(bytes(env_str, "utf-8") if mode == "wb" else env_str)
 
         if sys.version_info > (3, 0) and mode == "wb":
             f.write(bytes("{ " + "; } &&\n{ ".join(commands) + "; }", "utf-8"))
         else:

</details>

But neither this command or diff are exactly what I was hoping for. I was hoping that either the darker command could be updated to just apply the diff, which it doesn't seem like it can:

darker 09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354 llvm/utils/lit/lit/TestRunner.py
argument PATH: Error: Path(s) '09a275e8a4c2cea22bb67c7247fc892d5e73eb42...09671451af93ebe468971bc3e3b9882d09b7f354' do not exist in the working tree

Or I'd be able to copy and paste the diff contents and run git apply which I cannot because the path is not TestRunner.py, so git is expecting it to be llvm/utils/lit/lit/TestRunner.py. If I manually update the paths in the diff to be:

--- a/llvm/utils/lit/lit/TestRunner.py
+++ b/llvm/utils/lit/lit/TestRunner.py

Then applying it works, but I think it would be nice if either of these options worked without this extra step