Keep the first N columns visible by fasterit · Pull Request #2099 · htop-dev/htop

fasterit · 2026-08-31T11:17:49Z

Closes #2098

Assisted-by: OpenCode Zen

Closes htop-dev#2098 Assisted-by: OpenCode Zen

coderabbitai · 2026-08-31T11:29:23Z

📝 Walkthrough

Walkthrough

Adds configurable sticky columns for process and I/O list screens. Users can set the count through --keep-visible[=N], the display options panel, or configuration files. Rendering keeps leading columns fixed during horizontal scrolling. Header clicks account for pinned width and scroll position. Horizontal scrolling is clamped to valid bounds.

Assessment against linked issues

Objective	Addressed	Explanation
Keep leading process and I/O list columns visible during horizontal scrolling [`#2098`]	✅

Poem

Leading columns remain in view,
While wider rows pass by anew.
Scroll limits hold the viewport true,
Header clicks map to columns too.
The process list keeps its guide,
And I/O rows move side by side.

Merge Risk: 🔵 Low · up to abc81

The PR adds configurable sticky columns across command-line settings and display layout. Malformed or oversized numeric values may still be accepted, the settings UI limits the count to 100, and help/manual text do not fully match the behavior; these bounded issues warrant owner follow-up but do not indicate a security or availability risk.

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coderabbitai

Actionable comments posted: 4

ℹ️ Review info

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Run ID: 165ac4f7-ea30-43ee-bebe-3005e3e3ccdc

📥 Commits

Reviewing files that changed from the base of the PR and between e0dd9db and ae037ba.

📒 Files selected for processing (11)

CommandLine.c
DisplayOptionsPanel.c
MainPanel.c
Panel.c
Panel.h
Row.c
Row.h
Settings.c
Settings.h
Table.c
htop.1.in

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coderabbitai

Actionable comments posted: 1

ℹ️ Review info

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Configuration used: Repository UI

Review profile: ASSERTIVE

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Run ID: 2c0ae9ef-e19d-4d77-86d2-8d6f3851cda5

📥 Commits

Reviewing files that changed from the base of the PR and between 2796215 and f1e9775.

📒 Files selected for processing (9)

CommandLine.c
DisplayOptionsPanel.c
MainPanel.c
Row.c
Row.h
Settings.c
Settings.h
Table.c
htop.1.in

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

Assisted-by: OpenCode Zen

DLange is not convinced...

coderabbitai

Actionable comments posted: 1

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📥 Commits

Reviewing files that changed from the base of the PR and between f1e9775 and abc8116.

📒 Files selected for processing (2)

CommandLine.c
Row.c

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coderabbitai · 2026-09-01T22:16:43Z

+            if (sscanf(optarg, "%16zd", &parsed) != 1) {
+               fprintf(stderr, "Error: invalid value \"%s\" for --keep-visible.\n", optarg);
+               return STATUS_ERROR_EXIT;
+            }
+
+            if (parsed < 0) {
+               fprintf(stderr, "Error: --keep-visible must not be negative.\n");
+               return STATUS_ERROR_EXIT;
+            }
+
+            flags->keepColumnsVisible = (size_t) parsed;


🎯 Functional Correctness | 🟡 Minor | ⚡ Quick win

🔎 Supported by static analysis

🏁 Script executed:

#!/bin/bash set -eu printf '%s\n' '--- CommandLine.c target and application path ---' sed -n '330,490p' CommandLine.c printf '%s\n' '--- keepColumnsVisible declarations and uses ---' rg -n -C 3 'keepColumnsVisible|keep-visible' --glob '*.{c,h}'

Repository: htop-dev/htop

Length of output: 5415

🏁 Script executed:

#!/bin/bash set -u printf '%s\n' '--- tracked files defining the command-line settings type ---' git ls-files | rg '(^|/)(CommandLine|Settings|Config).*\\.(c|h)$' || true printf '%s\n' '--- all exact references ---' rg -n -C 3 'keepColumnsVisible|keep-visible' . || true printf '%s\n' '--- relevant status definitions ---' rg -n -C 3 'STATUS_ERROR_EXIT|typedef enum.*CommandLine|CommandLineStatus' CommandLine.c CommandLine.h *.h *.c 2>/dev/null || true

Repository: htop-dev/htop

Length of output: 19508

Reject partial and out-of-range values for --keep-visible.

sscanf accepts numeric prefixes, so --keep-visible=1x succeeds. Values above INT_MAX are accepted and narrowed to int before assignment to settings->keepColumnsVisible. Parse the complete argument and reject values outside 0..INT_MAX.

@fasterit sscanf is overkill here; strtoull + errno/retval check should do just fine and gives proper error handling.

Explorer09 · 2026-09-05T10:17:34Z

   printf("-M --no-mouse                   Disable the mouse\n");
 #endif
   printf("   --no-meters                  Hide meters\n"
+          "   --keep-visible[=N]           Keep the first N columns visible when scrolling sideways (default 1)\n"


For simplicity, it's better to have the option argument of this mandatory. No need to document the behavior of --keep-visible (without option argument) as it's behavior is less stable than --keep-visible=1.

Explorer09 · 2026-09-05T10:20:07Z

+            }
+
+            if (parsed < 0) {
+               fprintf(stderr, "Error: --keep-visible must not be negative.\n");


Error message of this may be merged with the previous one. ("Invalid value") Save at least one line of code.

Explorer09 · 2026-09-05T10:23:04Z

      case KEY_CTRL('B'):
         if (this->scrollH > 0) {
            this->scrollH -= MAXIMUM(CRT_scrollHAmount, 0);
+            this->scrollH = MAXIMUM(this->scrollH, 0);


This should be cheery picked into its own commit as this is a bug fix not related to the feature.

Can you split a PR for this?

Explorer09 · 2026-09-05T10:24:28Z

+   int nColumns = 0;
+   while (fields[nColumns])
+      nColumns++;
+   if (!nColumns)


Suggested change

if (!nColumns)

if (nColumns <= 0)

Explorer09 · 2026-09-05T10:26:35Z


   for (int i = 0; fields[i]; i++) {
      int color;
+      bool pinned = (i < pinnedCount);


Suggested change

bool pinned = (i < pinnedCount);

bool isPinned = (i < pinnedCount);

Keep the first N columns visible

ae037ba

Closes htop-dev#2098 Assisted-by: OpenCode Zen

fasterit added the feature request Completely new feature requested label Aug 31, 2026

coderabbitai Bot reviewed Aug 31, 2026

View reviewed changes

Comment thread CommandLine.c Outdated

Comment thread htop.1.in

Comment thread Row.c

Comment thread Settings.c Outdated

Fix COMM pinned header width if "(merged)" is appended

2796215

Assisted-by: CodeRabbitAI

coderabbitai Bot reviewed Aug 31, 2026

View reviewed changes

Comment thread DisplayOptionsPanel.c

Daniel Lange added 2 commits September 2, 2026 00:01

Drop limit on max kept columns as per @BenBE's request

1e75b4d

Assisted-by: OpenCode Zen

Prefer size_t for ComandLineSettings.keepColumnsVisible

abc8116

DLange is not convinced...

BenBE force-pushed the keep-N-columns-visible branch from f1e9775 to abc8116 Compare September 1, 2026 22:01

coderabbitai Bot reviewed Sep 1, 2026

View reviewed changes

fasterit marked this pull request as ready for review September 3, 2026 18:13

BenBE added this to the 3.6.0 milestone Sep 5, 2026

Explorer09 reviewed Sep 5, 2026

View reviewed changes

	bool pinned = (i < pinnedCount);
	bool isPinned = (i < pinnedCount);

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coderabbitai Bot commented Aug 31, 2026 •

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Explorer09 Sep 5, 2026 •

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