IWYU: treat stdio.h the same way as cstdio (#319)

aaronliu0130 · cclauss · web-flow · commit 80da3c1ef37a · 2025-03-04T18:52:25.000-05:00
Fixes #302 --------- Co-authored-by: Christian Clauss <cclauss@me.com>
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -8,6 +8,7 @@ Changelog
 Yet another overdue... hotfix. Sorry this took so long.
 
 * The false positive for indented function parameters in namespaces was eradicated.
+* build/include-what-you-use now recognizes c-style headers, such as <stdio.h> for symbols from <cstdio>. (https://github.com/cpplint/cpplint/pull/306)
 
 2.0 (2024-10-06)
 ================
diff --git a/cpplint.py b/cpplint.py
@@ -6226,12 +6226,15 @@ def CheckForIncludeWhatYouUse(filename, clean_lines, include_state, error,
                        for item in sublist])
 
   # All the lines have been processed, report the errors found.
-  for required_header_unstripped in sorted(required, key=required.__getitem__):
-    template = required[required_header_unstripped][1]
-    if required_header_unstripped.strip('<>"') not in include_dict:
-      error(filename, required[required_header_unstripped][0],
+  for header in sorted(required, key=required.__getitem__):
+    template = required[header][1]
+    header_stripped = header.strip('<>"')
+    if (header_stripped not in include_dict
+            and not (header_stripped[0] == 'c'
+                     and (header_stripped[1:] + '.h') in include_dict)):
+      error(filename, required[header][0],
             'build/include_what_you_use', 4,
-            'Add #include ' + required_header_unstripped + ' for ' + template)
+            'Add #include ' + header + ' for ' + template)
 
 
 _RE_PATTERN_EXPLICIT_MAKEPAIR = re.compile(r'\bmake_pair\s*<')
diff --git a/cpplint_unittest.py b/cpplint_unittest.py
@@ -1123,6 +1123,9 @@ def testIncludeWhatYouUse(self):
     self.TestIncludeWhatYouUse(
         'printf("hello world");',
         'Add #include <cstdio> for printf  [build/include_what_you_use] [4]')
+    self.TestIncludeWhatYouUse(
+      """#include <stdio.h>
+      printf("hello world");""", '')  # Avoid false positives w/ c-style include
     self.TestIncludeWhatYouUse(
         'void a(const string &foobar);',
         'Add #include <string> for string  [build/include_what_you_use] [4]')
diff --git a/samples/vlc-sample/simple.def b/samples/vlc-sample/simple.def
@@ -4,7 +4,7 @@ src/*
 Done processing src/libvlc.c
 Done processing src/libvlc.h
 Done processing src/missing.c
-Total errors found: 602
+Total errors found: 601
 
 src/libvlc.c:41:  Found C system header after other header. Should be: libvlc.h, c system, c++ system, other.  [build/include_order] [4]
 src/libvlc.c:47:  Found C system header after other header. Should be: libvlc.h, c system, c++ system, other.  [build/include_order] [4]
@@ -367,7 +367,6 @@ src/libvlc.c:627:  Missing space before ( in if(  [whitespace/parens] [5]
 src/libvlc.c:629:  Extra space after ( in function call  [whitespace/parens] [4]
 src/libvlc.c:629:  Extra space before )  [whitespace/parens] [2]
 src/libvlc.c:640:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
-src/libvlc.c:223:  Add #include <cstdio> for fclose  [build/include_what_you_use] [4]
 src/libvlc.h:0:  No #ifndef header guard found, suggested CPP variable is: SAMPLES_VLC_SAMPLE_SRC_LIBVLC_H_  [build/header_guard] [5]
 src/libvlc.h:34:  Extra space before ( in function call  [whitespace/parens] [4]
 src/libvlc.h:35:  Extra space before ( in function call  [whitespace/parens] [4]
